.. Autogenerated. Do not edit.

..	-*- mode: rst-mode -*-
..
.. Note: This file includes further autogenerated ones.
..
.. Version number is filled in automatically.
.. |version| replace:: 2.2.0-6

===========
ZeekControl
===========

.. rst-class:: opening

    This document summarizes installation and use of *ZeekControl*,
    a tool for operating Zeek installations. *ZeekControl*
    has two modes of operation: a *stand-alone* mode for
    managing a traditional, single-system Zeek setup; and a *cluster*
    mode for maintaining a multi-system setup of coordinated Zeek
    instances load-balancing the work across a set of independent
    machines.  Once installed, the operation is pretty similar
    for both types; just keep in mind that if this document refers to
    "nodes" and you're in a stand-alone setup, there is only a
    single one and no worker/proxies.

.. contents::

Download
--------

You can find the latest ZeekControl release for download at
https://www.zeek.org/download.

ZeekControl's git repository is located at https://github.com/zeek/zeekctl

This document describes ZeekControl |version|. See the ``CHANGES``
file for version history.

Prerequisites
-------------

Running ZeekControl requires the following prerequisites:

  - A Unix system. FreeBSD, Linux, and Mac OS X are supported and
    should work out of the box. Other Unix systems will quite likely
    require some tweaking.

  - A version of *Python* >= 3.5 (on FreeBSD, the package "pyXY-sqlite3" must
    also be installed for whatever your Python X.Y version is).

  - A *bash* (note that on FreeBSD, *bash* is not installed by default).

  - If *sendmail* is installed, then ZeekControl can send mail (for a cluster
    setup, it would be needed on the manager only).  Otherwise, ZeekControl
    will not attempt to send mail.

  - If *gdb* (*lldb* on Mac OS X, which is included with Xcode) is installed
    and if Zeek crashes with a core dump, then ZeekControl can include
    a backtrace in its crash report (that can be helpful for debugging
    problems with Zeek).  Otherwise, crash reports will not include a backtrace.

For a cluster setup that spans more than one machine, there are
additional requirements:

  - All machines in the cluster must be running exactly the *same* operating
    system (even the version must be the same).

  - Every host in the cluster must have *rsync* installed.

  - The manager host must have *ssh* installed, and every other host in the
    cluster must have *sshd* installed and running.

  - Decide which user account will be running ZeekControl, and then make sure
    this user account is set up on all hosts in your cluster.
    Note that if you plan to run zeekctl using sudo (i.e., "sudo zeekctl"), then
    the user running zeekctl will be "root" (and in that case the user running
    sudo does not need to exist on the other hosts in your cluster).

  - Make sure the user running ZeekControl can ``ssh`` from the manager host
    to each of the other hosts in your cluster, and this must work without
    being prompted for anything (one way to accomplish this is to use ssh
    public key authentication).  You will need to try this manually before
    attempting to run zeekctl, because zeekctl uses ssh to connect to other
    hosts in your cluster.

If you're using a load-balancing method (such as PF_RING), then there is
additional software to install (for details, see the
:doc:`Cluster Configuration <../../configuration/index>` documentation).


Installation
------------

Follow the directions to install Zeek and ZeekControl
in the :doc:`Installing Zeek <../../install/install>`
documentation.  Note that if you are planning to run Zeek in a cluster
configuration, then you need to install Zeek and ZeekControl only on the
manager host (the ZeekControl install_ or deploy_ commands will install Zeek
and all required scripts to the other hosts in your cluster).


Configuration
-------------

Before attempting to run ZeekControl, you first need to edit the ``zeekctl.cfg``,
``node.cfg``, and ``networks.cfg`` files.  All three of these configuration
files contain a valid configuration by default, but you might need to
customize a few things.

First, edit the ``node.cfg`` file and specify the nodes that you will be
running.  You need to decide whether you will be running Zeek standalone or
in a cluster.  For a standalone configuration, there must be only one Zeek node
defined in this file.  For a cluster configuration, at a minimum there
must be a manager node, a proxy node, and one or more worker nodes.
There is a :doc:`Cluster Configuration <../../configuration/index>`
guide that provides examples and additional information.

Each node defined in the ``node.cfg`` file has a set of options.  A few options
are required to be specified on every node, and some options are allowed only
on certain node types (zeekctl will issue an error if you make a mistake).
By default, the ``node.cfg`` file contains a valid configuration for
a standalone setup and has a valid cluster configuration commented-out.
If you want to use the default configuration, then at least check if
the "interface" option is set correctly for your system.  For a
description of every option available for nodes, see the `Node`_ section below.

In the ``zeekctl.cfg`` file, you should review the ZeekControl options and
check if any are not set correctly for your environment.  The options have
default values that are reasonable for most users (the MailTo_ option is
probably the one that you will most likely want to change), but for a
description of every ZeekControl option, see the `Option Reference`_ section
below.

ZeekControl options are used in three different ways:  some options
override the value of a Zeek script constant (these are noted in the
documentation), some affect only ZeekControl itself, and others affect Zeek.

Finally, edit the ``networks.cfg`` file and add each network (using standard
CIDR notation) that is considered local to the monitored environment (by
default, the ``networks.cfg`` file just lists the private IPv4 address spaces).

The information in the ``networks.cfg`` file is used when creating connection
summary reports.  Also, ZeekControl takes the information in the
``networks.cfg`` file and puts it in the global Zeek script constant
``Site::local_nets``, and this global constant is used by several
standard Zeek scripts.


Basic Usage
-----------

There are two ways to run ZeekControl commands:  by specifying a ZeekControl
command on the command-line (e.g. "zeekctl deploy"), or by entering
ZeekControl's interactive shell by running the zeekctl script without
any arguments (e.g. "zeekctl").  The interactive shell expects
commands on its command-line::

  > zeekctl
  Welcome to ZeekControl x.y

  Type "help" for help.

  [ZeekControl] >

As the message says, type help_ to see a list of
all commands. We will now briefly summarize the most important
commands. A full reference follows `Command Reference`_.

If this is the first time you are running ZeekControl, then the first command
you must run is the ZeekControl deploy_ command.  The "deploy" command
will make sure all of the files needed by ZeekControl and Zeek are brought
up-to-date based on the configuration specified in the ``zeekctl.cfg``,
``node.cfg``, and ``networks.cfg`` files.  It will also check if there
are any syntax errors in your Zeek policy scripts. For a cluster setup it will
copy all of the required scripts and executables to all the other hosts
in your cluster.  Then it will successively start the logger, manager,
proxies, and workers (for a standalone configuration, only one Zeek instance
will be started).

The status_ command can be used to check that all nodes are "running".
If any nodes have a status of "crashed", then use the diag_ command to
see diagnostic information (you can specify the name of a crashed node
as an argument to the diag command to show diagnostics for only that one
node).

If you want to stop the monitoring, issue the stop_ command. After all
nodes have stopped, the status_ command should show all nodes as "stopped".

The exit_ command leaves the shell (you can exit ZeekControl while Zeek
is running).

Whenever the ZeekControl or Zeek configuration is modified in any way,
including changes to configuration files and site-specific policy
scripts or upgrading to a new version of Zeek, deploy_ must
be run (deploy will check all policy scripts, install all needed files, and
restart Zeek). No changes will take effect until deploy_ is run.


ZeekControl cron command
-----------------------

The main purpose of the ZeekControl cron_ command is to check for Zeek nodes
that have crashed, and to restart them.  The command also performs other
housekeeping tasks, such as removing expired log files, checking if there is
sufficient free disk space, etc.  Although this command can be run directly
by a user, it is intended to be run from a cron job so that crashed nodes
will be restarted automatically.

For example, to setup a cron job that runs once every
five minutes, insert the following entry into the crontab of the
user running ZeekControl (change the path to the actual location of zeekctl
on your system) by running the ``crontab -e`` command::

      */5 * * * * /usr/local/zeek/bin/zeekctl cron

It is important to make sure that the cron job runs as the same user that
normally runs zeekctl on your system.  For a cluster configuration, this
should be run only on the manager host.

Note that on some systems, the default PATH for cron jobs might not include
the directory where python or bash are installed (the symptoms of this
problem would be that "zeekctl cron" works when run directly by the user,
but does not work from a cron job).  The simplest fix for this problem
would be to redefine PATH on a line immediately before the line that
runs zeekctl in your crontab.

If the ``"zeekctl cron disable"`` command is run, then zeekctl cron will be
disabled (i.e., zeekctl cron won't do anything) until the
``"zeekctl cron enable"`` command is run.  To check the status at any
time, run ``"zeekctl cron ?"``.


Log Files
---------

Log rotation and archival
~~~~~~~~~~~~~~~~~~~~~~~~~

While Zeek is running you can find the current set of (aggregated) logs
in ``logs/current`` (which is a symlink to the corresponding spool directory).
In a cluster setup, logs are written on the logger host (however, if there
is no logger defined in your node.cfg, then the manager writes logs).

Zeek logs are automatically rotated once per hour by default, or whenever Zeek
is stopped.  A rotated log is renamed to contain a timestamp in the filename.
For example, the ``conn.log`` might be renamed to
``conn.2015-01-20-15-23-42.log``.

Immediately after a log is rotated, it is archived automatically.  When a log
is archived, it is moved to a subdirectory of ``logs/`` named by date (such
as ``logs/2015-01-20``), then it is renamed again, and gzipped.  For example,
a rotated log file named ``conn.2015-01-20-15-23-42.log`` might be archived
to ``logs/2015-01-20/conn.15:48:23-16:00:00.log.gz``.  If the archival was
successful, then the original (rotated) log file is removed.

If, for some reason, a rotated log file cannot be archived then it will be
left in the node's working directory.  Next time when ZeekControl either stops
Zeek or tries to restart a crashed Zeek, it will try to archive such log files
again.  If this attempt fails, then an email is sent which contains the
name of a directory where any such unarchived logs can be found.

Log files created only when using ZeekControl
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

There are several log files that are not created by Zeek, but rather are
created only when using ZeekControl to run Zeek.

When ZeekControl starts Zeek it creates two files "stdout.log" and "stderr.log",
which just capture stdout and stderr from Zeek.  Although these are not
actually Zeek logs, they might contain useful error or diagnostic information.
The contents of these files are included in crash reports and also
in the output of the "zeekctl diag" command.

Also, whenever logs are rotated, a connection summary report is generated if
the `trace-summary <http://www.zeek.org/sphinx/components/trace-summary/README.html>`_
tool is installed.  Although these are not actually Zeek logs, they follow
the same filename convention as other Zeek logs and they have the filename
prefix "conn-summary".  If you don't want these connection summary files
to be created, then you can set the value of the TraceSummary_ option to
an empty string.


Zeek Scripts
-----------

Site-specific Customization
~~~~~~~~~~~~~~~~~~~~~~~~~~~

If you want to adapt the Zeek policy to the local environment, then
you will most likely need to write local policy scripts.

Sample local policy scripts (which you can edit)
are located in ``share/zeek/site``.  The file called ``local.zeek`` gets
loaded automatically.

The recommended way to modify the policy is to use only "@load" directives
in the ``local.zeek`` script.  For example, you can add a "@load" directive
to load a Zeek policy script that is included with Zeek but is not loaded
by default.  You can also create custom site-specific
policy scripts in the same directory as the ``local.zeek`` script, and "@load"
them from the ``local.zeek`` script.  For example, you could create
your own Zeek script ``mypolicy.zeek`` in the ``share/zeek/site`` directory,
and then add a line "@load mypolicy" (without the quotes) to the ``local.zeek``
script.

After creating or modifying your local policy scripts, you must install them
by using the ZeekControl "install" or "deploy" command.  Next, you can use the
ZeekControl "scripts" command to verify that your new scripts will be loaded
when you start Zeek.


Load Order of Scripts
~~~~~~~~~~~~~~~~~~~~~

When writing custom site-specific policy scripts, it can be useful
to know in which order the scripts are loaded.  For example, if more than
one script sets a value for the same global variable, then the value that
takes effect is the one set by the last such script loaded.  The
ZeekControl "scripts" command shows the load order of every script
loaded by Zeek.

When Zeek starts up, the first script it loads is init-bare.zeek, followed
by init-default.zeek (keep in mind that each of these scripts loads many
other scripts).  Note that these are the only scripts that are automatically
loaded when running Zeek directly (instead of using ZeekControl to run Zeek).

The next script loaded is the local.zeek script.  By default, this script
loads a variety of other scripts.  You can edit local.zeek and comment-out
anything that your site doesn't need (or add new "@load" directives).

Next, the "zeekctl" script package is loaded.  This consists of some standard
settings that ZeekControl needs.

The next scripts loaded are ``local-networks.zeek`` and ``zeekctl-config.zeek``.
These scripts are automatically generated by ZeekControl based on the
contents of the ``networks.cfg`` and ``zeekctl.cfg`` files.  Also, some
ZeekControl plugins might generate script code that will be automatically
inserted into the ``zeekctl-config.zeek`` script.

The last scripts loaded are any node-specific scripts specified with the
option ``aux_scripts`` in ``node.cfg``.  This option is seldom ever
needed, but can be used to load additional scripts to individual nodes only.
For example, one could add a script ``experimental.zeek`` to a single worker
for trying out new experimental code.


Mails
-----

There are several situations when ZeekControl sends mail to the address given in
MailTo_ (note that ZeekControl will not be able to send any mail when the
value of the SendMail_ option is an empty string):

1. When the "zeekctl cron" command runs it performs various tasks (such as
   checking available disk space, expiring old log files, etc.).  If
   any problems occur, a mail will be sent containing a list of those issues.
   In order to reduce the amount of mail, the value of the following options
   can be changed (see documentation of each option):  MailHostUpDown_,
   MinDiskSpace_, StatsLogEnable_, MailReceivingPackets_.

2. When ZeekControl tries to start or stop (via any of these commands:
   start, stop, restart, deploy, or cron) a node that has crashed,
   a crash report is mailed (one for each crashed node).  The crash report
   is essentially just the output of the "zeekctl diag" command.

3. When ZeekControl stops Zeek or restarts a crashed Zeek, if any log files
   could not be archived, then mail will be sent to warn about this problem.
   This mail can be disabled by setting ``MailArchiveLogFail=0``.

4. If `trace-summary <http://www.zeek.org/sphinx/components/trace-summary/README.html>`_
   is installed, a traffic summary is mailed each rotation interval.  To
   disable this mail, set ``MailConnectionSummary=0`` (however, the
   connection summary file will still be created and archived along with
   all other log files).


Using ZeekControl as an unprivileged user
----------------------------------------

If you decide to run ZeekControl as an unprivileged user, there are a
few issues that you may encounter.

If you installed Zeek and ZeekControl as the "root" user, then you will need
to adjust the ownership or permissions of the "logs" and "spool" directories
(and everything in those directories) so that the user running ZeekControl
has write permission.

If you're using a cluster setup that spans multiple machines, and if
your ZeekControl ``install`` or ``deploy`` commands fail with a permission
denied error, then it's most likely due to the user running ZeekControl
not having permission to create the install prefix directory
(by default, this is ``/usr/local/zeek``) on each remote machine.
A simple workaround is to login to each machine in your cluster and
manually create the install prefix directory and then set ownership
or permissions of this directory so that the user who will run ZeekControl
has write access to it.

Finally, on the worker nodes (or the standalone node), Zeek must have access
to the target network interface in promiscuous mode.  If Zeek doesn't have
the necessary permissions, then it will fail almost immediately upon
startup.  A workaround for this is provided in the
`Zeek FAQ <https://www.zeek.org/documentation/faq.html#how-can-i-capture-packets-as-an-unprivileged-user>`_.


Zeek communication
-----------------

This section summarizes the network communication between Zeek and ZeekControl,
which is useful to understand if you need to reconfigure your firewall.  If
your firewall is preventing Zeek communication, then either the "deploy"
command or the "peerstatus" command will fail.

For a cluster setup, ZeekControl uses ssh to run commands on other hosts in
the cluster, so the manager host needs to connect to TCP port 22 on each
of the other hosts in the cluster.  Note that ZeekControl never attempts
to ssh to the localhost, so in a standalone setup ZeekControl does not use ssh.

Each instance of Zeek in a cluster needs to communicate directly with other
instances of Zeek regardless of whether these instances are running on the same
host or not.  Each proxy and worker needs to connect to the manager, and each
worker needs to connect to each proxy.  If one or more logger nodes are
defined, then each of the other nodes needs to connect to each of the loggers.

Note that you can change the port that Zeek listens on by changing the value
of the "ZeekPort" option in your ``zeekctl.cfg`` file (this should be needed
only if your system has another process that listens on the same port).  By
default, a standalone Zeek listens on TCP port 47760.  For a cluster setup,
the logger listens on TCP port 47761, and the manager listens on TCP port 47762
(or 47761 if no logger is defined).  Each proxy is assigned its own port
number, starting with one number greater than the manager's port.  Likewise,
each worker is assigned its own port starting one number greater than the
highest port number assigned to a proxy.

Finally, a few ZeekControl commands (such as "print" and "peerstatus") rely
on Broker to communicate with Zeek.  This means that for those commands to
function, ZeekControl needs to connect to each Zeek instance.

Command Reference
-----------------

The following summary lists all commands supported by ZeekControl.
If not specified otherwise, commands taking
*[<nodes>]* as arguments apply their action either to the given set of
nodes, to the manager node if "manager" is given, to all proxy nodes if
"proxies" is given, to all worker nodes if "workers" is given, or to all
nodes if none are given.


.. _capstats:

*capstats* *[<nodes>] [<interval>]*
    Determines the current load on the network interfaces monitored by
    each of the given worker nodes. The load is measured over the
    specified interval (in seconds), or by default over 10 seconds. This
    command uses the :doc:`capstats<../../components/capstats/README>`
    tool, which is installed along with ``zeekctl``.


.. _check:

*check* *[<nodes>]*
    Verifies a modified configuration in terms of syntactical correctness
    (most importantly correct syntax in policy scripts).
    
    Note that this command checks the site-specific policy files as found
    in SitePolicyPath_ rather than the ones installed by the install_
    command.  Therefore, new errors in a policy script can be detected
    before affecting currently running nodes, even when they need to be
    restarted.
    
    This command should be executed for each configuration change *before*
    using install_ to put the change into place.  However, when using the
    deploy command there is no need to first run check, because deploy
    automatically runs check before installing the policy scripts.


.. _cleanup:

*cleanup* *[--all] [<nodes>]*
    Clears the nodes' spool directories, but only for nodes that are not
    running. This implies that their persistent state is flushed. Nodes
    that were crashed are reset into the "stopped" state.
    
    If ``--all`` is specified, this command also removes the content of
    the node's TmpDir_, in particular deleting any data
    potentially saved there for reference from previous crashes.
    Generally, if you want to reset the installation back into a clean
    state, you can first stop_ all nodes, then execute
    ``cleanup --all``, then install_, and finally start_ all nodes
    again.


.. _config:

*config*
    Prints all configuration options with their current values.


.. _cron:

*cron* *[enable|disable|?] | [--no-watch]*
    This command has two modes of operation. Without arguments (or just
    ``--no-watch``), it performs a set of maintenance tasks, including
    the logging of various statistical information, expiring old log
    files, checking for dead hosts, and restarting nodes which terminated
    unexpectedly (the latter can be suppressed with the ``--no-watch``
    option if no auto-restart is desired). This mode is intended to be
    executed regularly via *cron*, as described in the installation
    instructions. While not intended for interactive use, no harm will be
    caused by executing the command manually: all the maintenance tasks
    will then just be performed one more time.
    
    The second mode is for interactive usage and determines if the regular
    tasks are indeed performed when ``zeekctl cron`` is executed. In other
    words, even with ``zeekctl cron`` in your crontab, you can still
    temporarily disable it by running ``cron disable``, and
    then later reenable with ``cron enable``. This can be helpful while
    working, e.g., on the ZeekControl configuration and ``cron`` would
    interfere with that. ``cron ?`` can be used to query the current state.


.. _deploy:

*deploy*
    Checks for errors in Zeek policy scripts, then does an install followed
    by a restart on all nodes.  This command should be run after any
    changes to Zeek policy scripts or the zeekctl configuration, and after
    Zeek is upgraded or even just recompiled.
    
    This command is equivalent to running the check_, install_, and
    restart_ commands, in that order.


.. _df:

*df* *[<nodes>]*
    Reports the amount of disk space available on the nodes. Shows only
    paths relevant to the zeekctl installation.


.. _diag:

*diag* *[<nodes>]*
    If a node has terminated unexpectedly, this command prints a (somewhat
    cryptic) summary of its final state including excerpts of any
    stdout/stderr output, resource usage, and also a stack backtrace if a
    core dump is found. The same information is sent out via mail when a
    node is found to have crashed (the "crash report"). While the
    information is mainly intended for debugging, it can also help to find
    misconfigurations (which are usually, but not always, caught by the
    check_ command).


.. _exec:

*exec* *<command line>*
    Executes the given Unix shell command line on all hosts configured to
    run at least one Zeek instance. This is handy to quickly perform an
    action across all systems.


.. _exit:

*exit*
    Terminates the shell.


.. _help:

*help*
    Prints a brief summary of all commands understood by the shell.


.. _install:

*install* *[--local]*
    Reinstalls on all nodes, including all configuration files and
    local policy scripts.
    
    The ``--local`` option is intended for testing or debugging.  It
    causes only the local host to be installed (i.e., no changes pushed
    out to any other hosts in the Zeek cluster).  Normally all nodes
    should be reinstalled at the same time, as any inconsistencies between
    them will lead to strange effects.
    
    This command must be executed after *all* changes to any part of
    the ZeekControl configuration or after upgrading to a new version
    of Zeek or ZeekControl, otherwise the modifications will not take effect.
    Before executing ``install``, it is recommended to verify the
    configuration with check_.  Note that when using the deploy command
    there is no need to first use the install command, because deploy
    automatically runs install before restarting the nodes.


.. _netstats:

*netstats* *[<nodes>]*
    Queries each of the nodes for their current counts of captured and
    dropped packets.


.. _nodes:

*nodes*
    Prints a list of all configured nodes.
    
    Note that the env_vars attribute includes the set of environment
    variables from the 'env_vars' option in both 'node.cfg' and
    'zeekctl.cfg' and also those set by any plugins.


.. _peerstatus:

*peerstatus* *[<nodes>]*
    Primarily for debugging, ``peerstatus`` reports statistics about the
    network connections cluster nodes are using to communicate with other
    nodes.


.. _print:

*print* *<id> [<nodes>]*
    Reports the *current* live value of the given Zeek script ID on all of
    the specified nodes (which obviously must be running). This can for
    example be useful to (1) check that policy scripts are working as
    expected, or (2) confirm that configuration changes have in fact been
    applied.  Note that IDs defined inside a Zeek namespace must be
    prefixed with ``<namespace>::`` (e.g.,
    ``print Log::enable_remote_logging``).


.. _process:

*process* *<trace> [options] [-- <scripts>]*
    Runs Zeek offline on a given trace file using the same configuration as
    when running live. It does, however, use the potentially
    not-yet-installed policy files in SitePolicyPath_ and disables log
    rotation. Additional Zeek command line flags and scripts can
    be given (each argument after a ``--`` argument is interpreted as
    a script).
    
    Upon completion, the command prints a path where the log files can be
    found. Subsequent runs of this command may delete these logs.
    
    In cluster mode, Zeek is run with *both* manager and worker scripts
    loaded into a single instance. While that doesn't fully reproduce the
    live setup, it is often sufficient for debugging analysis scripts.


.. _quit:

*quit*
    Terminates the shell.


.. _restart:

*restart* *[--clean] [<nodes>]*
    Restarts the given nodes, or all nodes if none are specified. The
    effect is the same as first executing stop_ followed
    by a start_, giving the same nodes in both cases.
    
    If ``--clean`` is given, the installation is reset into a clean state
    before restarting. More precisely, a ``restart --clean`` turns into
    the command sequence stop_, cleanup_, check_, install_, and
    start_.


.. _scripts:

*scripts* *[-c] [<nodes>]*
    Primarily for debugging Zeek configurations, the ``scripts``
    command lists all the Zeek scripts loaded by each of the nodes in the
    order they will be parsed by the node at startup.  The pathnames
    of each script are indented such that it is possible to determine
    from where a script was loaded based on the amount of indentation.
    
    If ``-c`` is given, the command operates as check_ does: it reads
    the policy files from their *original* location, not the copies
    installed by install_. The latter option is useful to check a
    not yet installed configuration.


.. _start:

*start* *[<nodes>]*
    Starts the given nodes, or all nodes if none are specified. Nodes
    already running are left untouched.


.. _status:

*status* *[<nodes>]*
    Prints the current status of the given nodes.
    
    For each node, the information shown includes the node's name and type,
    the host where the node will run, the status, the PID, and the
    date/time when the node was started.  The status column will usually
    show a status of either "stopped" or "running".  A status of
    "crashed" means that ZeekControl verified that Zeek is no longer
    running, but was expected to be running.


.. _stop:

*stop* *[<nodes>]*
    Stops the given nodes, or all nodes if none are specified. Nodes that
    are in the "crashed" state are reset to the "stopped" state, and
    nodes that are "stopped" are left untouched.


.. _top:

*top* *[<nodes>]*
    For each of the nodes, prints the status of the Zeek process in
    a *top*-like format, including CPU usage and memory consumption. If
    executed interactively, the display is updated frequently
    until key ``q`` is pressed. If invoked non-interactively, the
    status is printed only once.


Option Reference
----------------

This section summarizes the options that can be set in ``zeekctl.cfg``
for customizing the behavior of ZeekControl (the option names are not
case-sensitive). Usually, one only needs
to change the "user options", which are listed first. The "internal
options" are, as the name suggests, primarily used internally and set
automatically. They are documented here only for reference.

User Options
~~~~~~~~~~~~
.. _CommTimeout:

*CommTimeout* (int, default 10)
    The number of seconds to wait before assuming Broker communication events have timed out.

.. _CommandTimeout:

*CommandTimeout* (int, default 60)
    The number of seconds to wait for a command to return results.

.. _CompressCmd:

*CompressCmd* (string, default "gzip")
    If archived logs will be compressed, the command to use for that. The specified command must compress its standard input to standard output.

.. _CompressExtension:

*CompressExtension* (string, default "gz")
    If archived logs will be compressed, the file extension to use on compressed log files. When specifying a file extension, don't include the period character (e.g., specify 'gz' instead of '.gz').

.. _CompressLogs:

*CompressLogs* (bool, default 1)
    True to compress archived log files.

.. _CompressLogsInFlight:

*CompressLogsInFlight* (int, default 0)
    Set to greater than zero to compress archived log files as they're created instead of during rotation.  The value indicates the compression level to use between 1 and 9 (values of 6 or 7 are a typical choice to bias slightly more towards better compression at cost of performance). If this is enabled, the CompressLogs, and CompressCmd arguments will be ignored as the files are compressed automatically by Zeek.

.. _ControlTopic:

*ControlTopic* (string, default "zeek/control")
    The Broker topic name used for sending and receiving control messages to Zeek processes.

.. _CrashExpireInterval:

*CrashExpireInterval* (int, default 0)
    Number of days that crash directories are kept (zero means never expire).

.. _CronCmd:

*CronCmd* (string, default _empty_)
    A custom command to run everytime the cron command has finished.

.. _Debug:

*Debug* (bool, default 0)
    Enable extensive debugging output in spool/debug.log.

.. _Env_Vars:

*Env_Vars* (string, default _empty_)
    A comma-separated list of environment variables (e.g. env_vars=VAR1=123, VAR2=456) to set on all nodes immediately before starting Zeek.  Node-specific values (specified in the node configuration file) override these global values.

.. _HaveNFS:

*HaveNFS* (bool, default 0)
    True if shared files are mounted across all nodes via NFS (see the FAQ_).

.. _KeepLogs:

*KeepLogs* (string, default _empty_)
    A space-separated list of filename shell patterns of expired log files to keep (empty string means don't keep any expired log files). The filename shell patterns are not regular expressions and do not include any directories. For example, specifying 'conn.* dns*' will prevent any expired log files with filenames starting with 'conn.' or 'dns' from being removed. Finally, note that this option is ignored if log files never expire.

.. _LogDir:

*LogDir* (string, default "$\{ZeekBase}/logs")
    Directory for archived log files.

.. _LogExpireInterval:

*LogExpireInterval* (string, default "0")
    Time interval that archived log files are kept (a value of 0 means log files never expire).  The time interval is expressed as an integer followed by one of the following time units: day, hr, min.

.. _LogRotationInterval:

*LogRotationInterval* (int, default 3600)
    The frequency of log rotation in seconds for the manager/standalone node (zero to disable rotation). This overrides the Zeek script variable Log::default_rotation_interval.

.. _MailAlarmsInterval:

*MailAlarmsInterval* (int, default 86400)
    The frequency (in seconds) of sending alarm summary mails (zero to disable). This overrides the Zeek script variable Log::default_mail_alarms_interval.

.. _MailAlarmsTo:

*MailAlarmsTo* (string, default "$\{MailTo}")
    Destination address for alarm summary mails. Default is to use the same address as MailTo. This overrides the Zeek script variable Notice::mail_dest_pretty_printed.

.. _MailArchiveLogFail:

*MailArchiveLogFail* (bool, default 1)
    True to enable sending mail when log files fail to be archived.

.. _MailConnectionSummary:

*MailConnectionSummary* (bool, default 1)
    True to mail connection summary reports each log rotation interval (if false, then connection summary reports will still be generated and archived, but they will not be mailed). However, this option has no effect if the trace-summary script is not available.

.. _MailFrom:

*MailFrom* (string, default "Zeek <zeek@localhost>")
    Originator address for mails. This overrides the Zeek script variable Notice::mail_from.

.. _MailHostUpDown:

*MailHostUpDown* (bool, default 1)
    True to enable sending mail when zeekctl cron notices the availability of a host in the cluster to have changed.

.. _MailReceivingPackets:

*MailReceivingPackets* (bool, default 1)
    True to enable sending mail when zeekctl cron notices that an interface is not receiving any packets (note that such mail is not sent when StatsLogEnable is 0).

.. _MailReplyTo:

*MailReplyTo* (string, default _empty_)
    Reply-to address for zeekctl-generated mails.

.. _MailSubjectPrefix:

*MailSubjectPrefix* (string, default "[Zeek]")
    General Subject prefix for mails. This overrides the Zeek script variable Notice::mail_subject_prefix.

.. _MailTo:

*MailTo* (string, default "<user>")
    Destination address for non-alarm mails. This overrides the Zeek script variable Notice::mail_dest.

.. _MakeArchiveName:

*MakeArchiveName* (string, default "$\{ZeekBase}/share/zeekctl/scripts/make-archive-name")
    Script to generate filenames for archived log files.

.. _MemLimit:

*MemLimit* (string, default "unlimited")
    Maximum amount of memory for Zeek processes to use (in KB, or the string 'unlimited').

.. _MinDiskSpace:

*MinDiskSpace* (int, default 5)
    Minimum percentage of disk space available before zeekctl cron mails a warning.  If this value is 0, then no warning will be sent.

.. _PFRINGClusterID:

*PFRINGClusterID* (int, default 21)
    If PF_RING flow-based load balancing is desired, this is where the PF_RING cluster id is defined.  In order to use PF_RING, the value of this option must be non-zero.

.. _PFRINGClusterType:

*PFRINGClusterType* (string, default "4-tuple")
    If PF_RING flow-based load balancing is desired, this is where the PF_RING cluster type is defined.  Allowed values are: 2-tuple, 4-tuple, 5-tuple, tcp-5-tuple, 6-tuple, or round-robin.  Zeek must be linked with PF_RING's libpcap wrapper and PFRINGClusterID must be non-zero for this option to work.

.. _PFRINGFirstAppInstance:

*PFRINGFirstAppInstance* (int, default 0)
    The first application instance for a PF_RING dnacluster interface to use.  Zeekctl will start at this application instance number and increment for each new process running on that DNA cluster.  Zeek must be linked with PF_RING's libpcap wrapper, PFRINGClusterID must be non-zero, and you must be using PF_RING+DNA and libzero for this option to work.

.. _Prefixes:

*Prefixes* (string, default "local")
    Additional script prefixes for Zeek, separated by colons. Use this instead of @prefix.

.. _SaveTraces:

*SaveTraces* (bool, default 0)
    True to let backends capture short-term traces via '-w'. These are not archived but might be helpful for debugging.

.. _SendMail:

*SendMail* (string, default "@SENDMAIL@")
    Location of the sendmail binary.  Make this string blank to prevent email from being sent. The default value is configuration-dependent and determined automatically by CMake at configure-time. This overrides the Zeek script variable Notice::sendmail.

.. _SitePluginPath:

*SitePluginPath* (string, default _empty_)
    Directories to search for custom plugins (i.e., plugins that are not included with zeekctl), separated by colons.

.. _SitePolicyPath:

*SitePolicyPath* (string, default "$\{PolicyDir}/site")
    Directories to search for local (i.e., site-specific) policy files, separated by colons. For each such directory, all files and subdirectories are copied to PolicyDirSiteInstall during zeekctl 'install' or 'deploy' (however, if the same file or subdirectory is found in more than one such directory, then only the first one encountered will be used).

.. _SitePolicyScripts:

*SitePolicyScripts* (string, default "local.zeek")
    Space-separated list of local policy files that will be automatically loaded for all Zeek instances.  Scripts listed here do not need to be explicitly loaded from any other policy scripts.

.. _StatsLogEnable:

*StatsLogEnable* (bool, default 1)
    True to enable ZeekControl to write statistics to the stats.log file.

.. _StatsLogExpireInterval:

*StatsLogExpireInterval* (int, default 0)
    Number of days entries in the stats.log file are kept (zero means never expire).

.. _StatusCmdShowAll:

*StatusCmdShowAll* (bool, default 0)
    True to have the status command show all output, or False to show only some of the output (peer information will not be collected or shown, so the command will run faster).

.. _StopTimeout:

*StopTimeout* (int, default 60)
    The number of seconds to wait before sending a SIGKILL to a node which was previously issued the 'stop' command but did not terminate gracefully.

.. _StopWait:

*StopWait* (bool, default 0)
    True to force the stop command to wait for the post-terminate script to finish, or False to let post-terminate finish in the background.

.. _TimeFmt:

*TimeFmt* (string, default "%d %b %H:%M:%S")
    Format string to print date/time specifications (see 'man strftime').

.. _TimeMachineHost:

*TimeMachineHost* (string, default _empty_)
    If the manager should connect to a Time Machine, the address of the host it is running on.

.. _TimeMachinePort:

*TimeMachinePort* (string, default "47757/tcp")
    If the manager should connect to a Time Machine, the port it is running on (in Zeek syntax, e.g., 47757/tcp).

.. _ZeekArgs:

*ZeekArgs* (string, default _empty_)
    Additional arguments to pass to Zeek on the command-line (e.g. zeekargs=-f "tcp port 80").

.. _ZeekPort:

*ZeekPort* (int, default 47760)
    The TCP port number that Zeek will listen on. For a cluster configuration, each node in the cluster will automatically be assigned a subsequent port to listen on.


Internal Options
~~~~~~~~~~~~~~~~

.. _BinDir:

*BinDir* (string, default "$\{ZeekBase}/bin")
    Directory for executable files.

.. _BrokerDBDir:

*BrokerDBDir* (string, default "$\{ZeekBase}/spool/brokerstore")
    Directory for data stores of persistent Broker-backed tables.

.. _CapstatsPath:

*CapstatsPath* (string, default "$\{bindir}/capstats")
    Path to capstats binary; empty if not available.

.. _CfgDir:

*CfgDir* (string, default "$\{ZeekBase}/etc")
    Directory for configuration files.

.. _DebugLog:

*DebugLog* (string, default "$\{SpoolDir}/debug.log")
    Log file for debugging information.

.. _DefaultStoreDir:

*DefaultStoreDir* (string, default "$\{SpoolDir}/stores")
    Default directory where Broker data stores will be written if user has not provided further customizations on a per-store basis.

.. _HelperDir:

*HelperDir* (string, default "$\{ZeekBase}/share/zeekctl/scripts/helpers")
    Directory for zeekctl helper scripts.

.. _LibDir:

*LibDir* (string, default _empty_)
    Directory for library files.

.. _LibDir64:

*LibDir64* (string, default "$\{ZeekBase}/lib64")
    Directory for 64-bit architecture library files.

.. _LibDirInternal:

*LibDirInternal* (string, default "$\{LibDir}/zeek/python/zeekctl")
    Directory for zeekctl-specific library files.

.. _LocalNetsCfg:

*LocalNetsCfg* (string, default "$\{CfgDir}/networks.cfg")
    File defining the local networks.

.. _LockFile:

*LockFile* (string, default "$\{SpoolDir}/lock")
    Lock file preventing concurrent shell operations.

.. _LogExpireMinutes:

*LogExpireMinutes* (int, default 0)
    Time interval (in minutes) that archived log files are kept (0 means they never expire).  Users should never modify this value (see the LogExpireInterval option).

.. _NodeCfg:

*NodeCfg* (string, default "$\{CfgDir}/node.cfg")
    Node configuration file.

.. _OS:

*OS* (string, default _empty_)
    Name of operating system as reported by uname.

.. _PcapBufsize:

*PcapBufsize* (int, default 128)
    Number of Mbytes to provide as buffer space when capturing from live interfaces via libpcap.

.. _PcapSnaplen:

*PcapSnaplen* (int, default 9216)
    Number of bytes per packet to capture from live interfaces via libpcap.

.. _PluginDir:

*PluginDir* (string, default "$\{LibDirInternal}/plugins")
    Directory where standard zeekctl plugins are located.

.. _PluginZeekDir:

*PluginZeekDir* (string, default "$\{LibDir}/zeek/plugins")
    Directory where Zeek plugins are located.  ZeekControl will search this directory tree for zeekctl plugins that are provided by any Zeek plugin.

.. _PolicyDir:

*PolicyDir* (string, default "$\{ZeekScriptDir}")
    Directory for standard policy files.

.. _PolicyDirSiteInstall:

*PolicyDirSiteInstall* (string, default "$\{SpoolDir}/installed-scripts-do-not-touch/site")
    Directory where the shell copies local (i.e., site-specific) policy scripts when installing.

.. _PolicyDirSiteInstallAuto:

*PolicyDirSiteInstallAuto* (string, default "$\{SpoolDir}/installed-scripts-do-not-touch/auto")
    Directory where the shell copies auto-generated local policy scripts when installing.

.. _PostProcDir:

*PostProcDir* (string, default "$\{ZeekBase}/share/zeekctl/scripts/postprocessors")
    Directory for log postprocessors.

.. _ScriptsDir:

*ScriptsDir* (string, default "$\{ZeekBase}/share/zeekctl/scripts")
    Directory for executable scripts shipping as part of zeekctl.

.. _SpoolDir:

*SpoolDir* (string, default "$\{ZeekBase}/spool")
    Directory for run-time data.

.. _StandAlone:

*StandAlone* (bool, default 0)
    True if running in stand-alone mode (see elsewhere).

.. _StateFile:

*StateFile* (string, default "$\{SpoolDir}/state.db")
    File storing the current zeekctl state.

.. _StaticDir:

*StaticDir* (string, default "$\{ZeekBase}/share/zeekctl")
    Directory for static, arch-independent files.

.. _StatsDir:

*StatsDir* (string, default "$\{LogDir}/stats")
    Directory where statistics are kept.

.. _StatsLog:

*StatsLog* (string, default "$\{SpoolDir}/stats.log")
    Log file for statistics.

.. _Time:

*Time* (string, default _empty_)
    Path to time binary.

.. _TmpDir:

*TmpDir* (string, default "$\{SpoolDir}/tmp")
    Directory for temporary data.

.. _TmpExecDir:

*TmpExecDir* (string, default "$\{SpoolDir}/tmp")
    Directory where binaries are copied before execution.  This option is ignored if HaveNFS is 0.

.. _TraceSummary:

*TraceSummary* (string, default "$\{bindir}/trace-summary")
    Path to trace-summary script (empty if not available). Make this string blank to disable the connection summary reports.

.. _Version:

*Version* (string, default _empty_)
    Version of the zeekctl.

.. _Zeek:

*Zeek* (string, default "$\{BinDir}/zeek")
    Path to Zeek binary.

.. _ZeekBase:

*ZeekBase* (string, default _empty_)
    Base path of zeekctl installation on all nodes.


Plugins
-------

ZeekControl provides a plugin interface to extend its functionality. A
plugin is written in Python and can do any, or all, of the following:

    * Perform actions before or after any of the standard ZeekControl
      commands is executed. When running before the actual command, it
      can filter which nodes to operate or stop the execution
      altogether. When running after the command, it gets access to
      the commands success status on a per-node basis (where applicable).

    * Add custom commands to ZeekControl.

    * Add custom options to ZeekControl defined in ``zeekctl.cfg``.

    * Add custom keys to nodes defined in ``node.cfg``.

A plugin is written by deriving a new class from ZeekControl class
`Plugin`_. The Python script with the new plugin is then copied into a
plugin directory searched by ZeekControl at startup. By default,
ZeekControl searches ``<prefix>/lib/zeek/python/zeekctl/plugins``; additional directories
may be configured by setting the SitePluginPath_ option. Note that any plugin
script must end in ``*.py`` to be found. ZeekControl comes with some
example plugins that can be used as a starting point; see
the ``<prefix>/lib/zeek/python/zeekctl/plugins`` directory.

In the following, we document the API that is available to plugins. A
plugin must be derived from the `Plugin`_ class, and can use its
methods as well as those of the `Node`_ class.

.. _Plugin:

Class ``Plugin``
~~~~~~~~~~~~~~~~

class **Plugin**
     The class ``Plugin`` is the base class for all ZeekControl plugins.
     
     The class has a number of methods for plugins to override, and every
     plugin must at least override ``name()`` and ``pluginVersion()``.
     
     For each ZeekControl command ``foo``, there are two methods,
     ``cmd_foo_pre`` and ``cmd_foo_post``, that are called just before the
     command is executed and just after it has finished, respectively. The
     arguments these methods receive correspond to their command-line
     parameters, and are further documented below.
     
     The ``cmd_<XXX>_pre`` methods have the ability to prevent the command's
     execution, either completely or partially for those commands that take
     nodes as parameters. In the latter case, the method receives a list of
     nodes that the command is to be run on, and it can filter that list and
     returns modified version of nodes to actually use. The standard case would
     be returning simply the unmodified ``nodes`` parameter. To completely
     block the command's execution, return an empty list. To just not execute
     the command for a subset, remove the affected ones.  For commands that do
     not receive nodes as arguments, the return value is interpreted as boolean
     indicating whether command execution should proceed (True) or not (False).
     
     The ``cmd_<XXX>_post`` methods likewise receive the commands arguments as
     their parameter, as documented below. For commands taking nodes, the list
     corresponds to those nodes for which the command was actually executed
     (i.e., after any ``cmd_<XXX>_pre`` filtering).
     
     Note that if a plugin prevents a command from executing either completely or
     partially, it should report its reason via the ``message()`` or
     ``error()`` methods.
     
     If multiple plugins hook into the same command, all their
     ``cmd_<XXX>_{pre,post}`` are executed in undefined order. The command is
     executed on the intersection of all ``cmd_<XXX>_pre`` results.
     
     Finally, note that the ``restart`` command is just a combination of other
     commands and thus their callbacks are run in addition to the callbacks
     for ``restart``.

     .. _Plugin.debug:

     **debug** (self, msg)

         Logs a debug message in ZeekControl's debug log if enabled.

     .. _Plugin.error:

     **error** (self, msg)

         Reports an error to the user.

     .. _Plugin.execute:

     **execute** (self, node, cmd)

         Executes a command on the host for the given *node* of type
         `Node`_. Returns a tuple ``(success, output)`` in which ``success`` is
         True if the command ran successfully, and ``output`` is a string
         which contains the combined stdout/stderr output.

     .. _Plugin.executeParallel:

     **executeParallel** (self, cmds)

         Executes a set of commands in parallel on multiple hosts. ``cmds``
         is a list of tuples ``(node, cmd)``, in which the *node* is a `Node`_
         instance and *cmd* is a string with the command to execute for it. The
         method returns a list of tuples ``(node, success, output)``, in which
         ``success`` is True if the command ran successfully, and ``output`` is
         a string containing the combined stdout/stderr output for the
         corresponding ``node``.

     .. _Plugin.getGlobalOption:

     **getGlobalOption** (self, name)

         Returns the value of the global ZeekControl option *name*.
         
         See the output of ``zeekctl config`` for a complete list.

     .. _Plugin.getOption:

     **getOption** (self, name)

         Returns the value of one of the plugin's options, *name*.
         
         An option has a default value (see *options()*), which can be
         overridden by a user in ``zeekctl.cfg``. An option's value cannot be
         changed by the plugin.

     .. _Plugin.getState:

     **getState** (self, name)

         Returns the current value of one of the plugin's state variables,
         *name*. If it has not yet been set, an empty string will be returned.
         
         Different from options, state variables can be set by the plugin.
         They are persistent across restarts.
         
         Note that a plugin cannot query any global ZeekControl state variables.

     .. _Plugin.hosts:

     **hosts** (self, nodes)

         Returns a list of Node_ objects which is a subset of the list in
         *nodes*, such that only one node per host will be chosen.  If *nodes*
         is empty, then the returned list will be a subset of the entire list
         of configured nodes.

     .. _Plugin.message:

     **message** (self, msg)

         Reports a message to the user.

     .. _Plugin.nodes:

     **nodes** (self)

         Returns a list of all configured `Node`_ objects.

     .. _Plugin.parseNodes:

     **parseNodes** (self, names)

         Returns a tuple which contains two lists. The first list is a list
         of `Node`_ objects for a string of space-separated node names. If a
         name does not correspond to a known node, then the name is added
         to the second list in the returned tuple.

     .. _Plugin.setState:

     **setState** (self, name, value)

         Sets one of the plugin's state variables, *name*, to *value*.
         The change is permanent and will be recorded to disk.
         
         Note that a plugin cannot change any global ZeekControl state
         variables.

     .. _Plugin.cmd_capstats_post:

     **cmd_capstats_post** (self, nodes, interval)

         Called just after the ``capstats`` command has finished. Arguments
         are as with the ``pre`` method.
         
         This method can be overridden by derived classes. The default
         implementation does nothing.

     .. _Plugin.cmd_capstats_pre:

     **cmd_capstats_pre** (self, nodes, interval)

         Called just before the ``capstats`` command is run. It receives the
         list of nodes, and returns the list of nodes that should proceed with
         the command. *interval* is an integer with the measurement interval in
         seconds.
         
         This method can be overridden by derived classes. The default
         implementation does nothing.

     .. _Plugin.cmd_check_post:

     **cmd_check_post** (self, results)

         Called just after the ``check`` command has finished. It receives
         the list of 2-tuples ``(node, bool)`` indicating the nodes the command
         was executed for, along with their success status.
         
         This method can be overridden by derived classes. The default
         implementation does nothing.

     .. _Plugin.cmd_check_pre:

     **cmd_check_pre** (self, nodes)

         Called just before the ``check`` command is run. It receives the
         list of nodes, and returns the list of nodes that should proceed with
         the command.
         
         This method can be overridden by derived classes. The default
         implementation does nothing.

     .. _Plugin.cmd_cleanup_post:

     **cmd_cleanup_post** (self, nodes, all)

         Called just after the ``cleanup`` command has finished. Arguments
         are as with the ``pre`` method.
         
         This method can be overridden by derived classes. The default
         implementation does nothing.

     .. _Plugin.cmd_cleanup_pre:

     **cmd_cleanup_pre** (self, nodes, all)

         Called just before the ``cleanup`` command is run. It receives the
         list of nodes, and returns the list of nodes that should proceed with
         the command. *all* is boolean indicating whether the ``--all``
         argument has been given.
         
         This method can be overridden by derived classes. The default
         implementation does nothing.

     .. _Plugin.cmd_config_post:

     **cmd_config_post** (self)

         Called just after the ``config`` command has finished.
         
         This method can be overridden by derived classes. The default
         implementation does nothing.

     .. _Plugin.cmd_config_pre:

     **cmd_config_pre** (self)

         Called just before the ``config`` command is run. Returns a boolean
         indicating whether or not the command should run.
         
         This method can be overridden by derived classes. The default
         implementation does nothing.

     .. _Plugin.cmd_cron_post:

     **cmd_cron_post** (self, arg, watch)

         Called just after the ``cron`` command has finished. Arguments are
         as with the ``pre`` method.
         
         This method can be overridden by derived classes. The default
         implementation does nothing.

     .. _Plugin.cmd_cron_pre:

     **cmd_cron_pre** (self, arg, watch)

         Called just before the ``cron`` command is run. *arg* is an empty
         string if the command is executed without arguments. Otherwise, it is
         one of the strings: ``enable``, ``disable``, ``?``. *watch* is a
         boolean indicating whether the ``cron`` command should restart
         abnormally terminated Zeek processes; it's only valid if *arg* is empty.
         
         Returns a boolean indicating whether or not the ``cron`` command should
         run.
         
         This method can be overridden by derived classes. The default
         implementation does nothing.

     .. _Plugin.cmd_custom:

     **cmd_custom** (self, cmd, args, cmdout)

         Called when a command defined by the ``commands`` method is executed.
         *cmd* is the command (without the plugin's prefix), and *args* is a
         single string with all arguments.  It returns a CmdResult object
         containing the command results.
         
         If the arguments are actually node names, ``parseNodes`` can
         be used to get the `Node`_ objects.
         
         This method can be overridden by derived classes. The default
         implementation does nothing.

     .. _Plugin.cmd_deploy_post:

     **cmd_deploy_post** (self)

         Called just after the ``deploy`` command has finished.
         
         This method can be overridden by derived classes. The default
         implementation does nothing.

     .. _Plugin.cmd_deploy_pre:

     **cmd_deploy_pre** (self)

         Called just before the ``deploy`` command is run. Returns a
         boolean indicating whether or not the command should run.
         
         This method can be overridden by derived classes. The default
         implementation does nothing.

     .. _Plugin.cmd_df_post:

     **cmd_df_post** (self, nodes)

         Called just after the ``df`` command has finished. Arguments are as
         with the ``pre`` method.
         
         This method can be overridden by derived classes. The default
         implementation does nothing.

     .. _Plugin.cmd_df_pre:

     **cmd_df_pre** (self, nodes)

         Called just before the ``df`` command is run. It receives the
         list of nodes, and returns the list of nodes that should proceed with
         the command.
         
         This method can be overridden by derived classes. The default
         implementation does nothing.

     .. _Plugin.cmd_diag_post:

     **cmd_diag_post** (self, nodes)

         Called just after the ``diag`` command has finished. Arguments are
         as with the ``pre`` method.
         
         This method can be overridden by derived classes. The default
         implementation does nothing.

     .. _Plugin.cmd_diag_pre:

     **cmd_diag_pre** (self, nodes)

         Called just before the ``diag`` command is run. It receives the
         list of nodes, and returns the list of nodes that should proceed with
         the command.
         
         This method can be overridden by derived classes. The default
         implementation does nothing.

     .. _Plugin.cmd_exec_post:

     **cmd_exec_post** (self, cmdline)

         Called just after the ``exec`` command has finished. Arguments are
         as with the ``pre`` method.
         
         This method can be overridden by derived classes. The default
         implementation does nothing.

     .. _Plugin.cmd_exec_pre:

     **cmd_exec_pre** (self, cmdline)

         Called just before the ``exec`` command is run. *cmdline* is a
         string with the command line to execute.
         
         Returns a boolean indicating whether or not the ``exec`` command
         should run.
         
         This method can be overridden by derived classes. The default
         implementation does nothing.

     .. _Plugin.cmd_install_post:

     **cmd_install_post** (self)

         Called just after the ``install`` command has finished.
         
         This method can be overridden by derived classes. The default
         implementation does nothing.

     .. _Plugin.cmd_install_pre:

     **cmd_install_pre** (self)

         Called just before the ``install`` command is run. Returns a
         boolean indicating whether or not the command should run.
         
         This method can be overridden by derived classes. The default
         implementation does nothing.

     .. _Plugin.cmd_netstats_post:

     **cmd_netstats_post** (self, nodes)

         Called just after the ``netstats`` command has finished. Arguments
         are as with the ``pre`` method.
         
         This method can be overridden by derived classes. The default
         implementation does nothing.

     .. _Plugin.cmd_netstats_pre:

     **cmd_netstats_pre** (self, nodes)

         Called just before the ``netstats`` command is run. It receives the
         list of nodes, and returns the list of nodes that should proceed with
         the command.
         
         This method can be overridden by derived classes. The default
         implementation does nothing.

     .. _Plugin.cmd_nodes_post:

     **cmd_nodes_post** (self)

         Called just after the ``nodes`` command has finished.
         
         This method can be overridden by derived classes. The default
         implementation does nothing.

     .. _Plugin.cmd_nodes_pre:

     **cmd_nodes_pre** (self)

         Called just before the ``nodes`` command is run. Returns a
         boolean indicating whether or not the command should run.
         
         This method can be overridden by derived classes. The default
         implementation does nothing.

     .. _Plugin.cmd_peerstatus_post:

     **cmd_peerstatus_post** (self, nodes)

         Called just after the ``peerstatus`` command has finished.
         Arguments are as with the ``pre`` method.
         
         This method can be overridden by derived classes. The default
         implementation does nothing.

     .. _Plugin.cmd_peerstatus_pre:

     **cmd_peerstatus_pre** (self, nodes)

         Called just before the ``peerstatus`` command is run. It receives the
         list of nodes, and returns the list of nodes that should proceed with
         the command.
         
         This method can be overridden by derived classes. The default
         implementation does nothing.

     .. _Plugin.cmd_print_post:

     **cmd_print_post** (self, nodes, id)

         Called just after the ``print`` command has finished. Arguments are
         as with the ``pre`` method.
         
         This method can be overridden by derived classes. The default
         implementation does nothing.

     .. _Plugin.cmd_print_pre:

     **cmd_print_pre** (self, nodes, id)

         Called just before the ``print`` command is run. It receives the
         list of nodes, and returns the list of nodes that should proceed with
         the command. *id* is a string with the name of the ID to be printed.
         
         This method can be overridden by derived classes. The default
         implementation does nothing.

     .. _Plugin.cmd_process_post:

     **cmd_process_post** (self, trace, options, scripts, success)

         Called just after the ``process`` command has finished. Arguments
         are as with the ``pre`` method, plus an additional boolean *success*
         indicating whether Zeek terminated normally.
         
         This method can be overridden by derived classes. The default
         implementation does nothing.

     .. _Plugin.cmd_process_pre:

     **cmd_process_pre** (self, trace, options, scripts)

         Called just before the ``process`` command is run. It receives the
         *trace* to read from as a string, a list of additional Zeek *options*,
         and a list of additional Zeek *scripts*.
         
         Returns a boolean indicating whether or not the ``process`` command
         should run.
         
         This method can be overridden by derived classes. The default
         implementation does nothing.

     .. _Plugin.cmd_restart_post:

     **cmd_restart_post** (self, nodes)

         Called just after the ``restart`` command has finished. It receives
         a list of *nodes* indicating the nodes on which the command was
         executed.
         
         This method can be overridden by derived classes. The default
         implementation does nothing.

     .. _Plugin.cmd_restart_pre:

     **cmd_restart_pre** (self, nodes, clean)

         Called just before the ``restart`` command is run. It receives the
         list of nodes, and returns the list of nodes that should proceed with
         the command. *clean* is boolean indicating whether the ``--clean``
         argument has been given.
         
         This method can be overridden by derived classes. The default
         implementation does nothing.

     .. _Plugin.cmd_scripts_post:

     **cmd_scripts_post** (self, nodes, check)

         Called just after the ``scripts`` command has finished. Arguments
         are as with the ``pre`` method.
         
         This method can be overridden by derived classes. The default
         implementation does nothing.

     .. _Plugin.cmd_scripts_pre:

     **cmd_scripts_pre** (self, nodes, check)

         Called just before the ``scripts`` command is run. It receives the
         list of nodes, and returns the list of nodes that should proceed with
         the command. *check* is boolean indicating whether the ``-c``
         option was given.
         
         This method can be overridden by derived classes. The default
         implementation does nothing.

     .. _Plugin.cmd_start_post:

     **cmd_start_post** (self, results)

         Called just after the ``start`` command has finished. It receives
         the list of 2-tuples ``(node, bool)`` indicating the nodes the command
         was executed for, along with their success status.
         
         This method can be overridden by derived classes. The default
         implementation does nothing.

     .. _Plugin.cmd_start_pre:

     **cmd_start_pre** (self, nodes)

         Called just before the ``start`` command is run. It receives the
         list of nodes, and returns the list of nodes that should proceed with
         the command.
         
         This method can be overridden by derived classes. The default
         implementation does nothing.

     .. _Plugin.cmd_status_post:

     **cmd_status_post** (self, nodes)

         Called just after the ``status`` command has finished.  Arguments
         are as with the ``pre`` method.
         
         This method can be overridden by derived classes. The default
         implementation does nothing.

     .. _Plugin.cmd_status_pre:

     **cmd_status_pre** (self, nodes)

         Called just before the ``status`` command is run. It receives the
         list of nodes, and returns the list of nodes that should proceed with
         the command.
         
         This method can be overridden by derived classes. The default
         implementation does nothing.

     .. _Plugin.cmd_stop_post:

     **cmd_stop_post** (self, results)

         Called just after the ``stop`` command has finished. It receives
         the list of 2-tuples ``(node, bool)`` indicating the nodes the command
         was executed for, along with their success status.
         
         This method can be overridden by derived classes. The default
         implementation does nothing.

     .. _Plugin.cmd_stop_pre:

     **cmd_stop_pre** (self, nodes)

         Called just before the ``stop`` command is run. It receives the
         list of nodes, and returns the list of nodes that should proceed with
         the command.
         
         This method can be overridden by derived classes. The default
         implementation does nothing.

     .. _Plugin.cmd_top_post:

     **cmd_top_post** (self, nodes)

         Called just after the ``top`` command has finished. Arguments are
         as with the ``pre`` method. Note that when ``top`` is run
         interactively to auto-refresh continuously, this method will be called
         once after each update.
         
         This method can be overridden by derived classes. The default
         implementation does nothing.

     .. _Plugin.cmd_top_pre:

     **cmd_top_pre** (self, nodes)

         Called just before the ``top`` command is run. It receives the list
         of nodes, and returns the list of nodes that should proceed with the
         command. Note that when ``top`` is run interactively to auto-refresh
         continuously, this method will be called once before each update.
         
         This method can be overridden by derived classes. The default
         implementation does nothing.

     .. _Plugin.cmd_update_post:

     **cmd_update_post** (self, results)

         Called just after the ``update`` command has finished. It receives
         the list of 2-tuples ``(node, bool)`` indicating the nodes the command
         was executed for, along with their success status.
         
         This method can be overridden by derived classes. The default
         implementation does nothing.

     .. _Plugin.cmd_update_pre:

     **cmd_update_pre** (self, nodes)

         Called just before the ``update`` command is run. It receives the
         list of nodes, and returns the list of nodes that should proceed with
         the command.
         
         This method can be overridden by derived classes. The default
         implementation does nothing.

     .. _Plugin.commands:

     **commands** (self)

         Returns a set of custom commands provided by the
         plugin.
         
         The return value is a list of 3-tuples each having the following
         elements:
         
             ``command``
                 A string with the command's name. Note that the command name
                 exposed to the user will be prefixed with the plugin's prefix
                 as returned by *prefix()* (e.g., ``myplugin.mycommand``, or
                 just ``myplugin`` if the command name is an empty string).
         
             ``arguments``
                 A string describing the command's arguments in a textual form
                 suitable for use in the ``help`` command summary (e.g.,
                 ``[<nodes>]`` for a command taking an optional list of nodes).
                 Empty if no arguments are expected.
         
             ``description``
                 A string with a description of the command's semantics suitable
                 for use in the ``help`` command summary.
         
         
         This method can be overridden by derived classes. The implementation
         must not call the parent class' implementation. The default
         implementation returns an empty list.

     .. _Plugin.done:

     **done** (self)

         Called once just before ZeekControl terminates. This method can do
         any cleanup the plugin may require.
         
         This method can be overridden by derived classes. The default
         implementation does nothing.

     .. _Plugin.hostStatusChanged:

     **hostStatusChanged** (self, host, status)

         Called when ZeekControl's ``cron`` command finds the availability of
         a cluster system to have changed. Initially, all systems are assumed
         to be up and running. Once ZeekControl notices that a system isn't
         responding (defined as not accepting SSH sessions), it calls
         this method, passing in a string with
         the name of the *host* and a boolean *status* set to False. Once the
         host becomes available again, the method will be called again for the
         same host with *status* now set to True.
         
         Note that ZeekControl's ``cron`` tracks a host's availability across
         execution, so if the next time it's run the host is still down, this
         method will not be called again.
         
         This method can be overridden by derived classes. The default
         implementation does nothing.

     .. _Plugin.init:

     **init** (self)

         Called once just before ZeekControl starts executing any commands.
         This method can do any initialization that the plugin may require.
         
         Note that when this method executes, ZeekControl guarantees that all
         internals are fully set up (e.g., user-defined options are available).
         This may not be the case when the class ``__init__`` method runs.
         
         Returns a boolean, indicating whether the plugin should be used. If it
         returns ``False``, the plugin will be removed and no other methods
         called.
         
         This method can be overridden by derived classes. The default
         implementation always returns True.

     .. _Plugin.name:

     **name** (self)

         Returns a string with a descriptive name for the plugin (e.g.,
         ``"TestPlugin"``). The name must not contain any whitespace.
         
         This method must be overridden by derived classes. The implementation
         must not call the parent class' implementation.

     .. _Plugin.nodeKeys:

     **nodeKeys** (self)

         Returns a list of names of custom keys for nodes (the value of a
         key can be specified in ``node.cfg`` for any node defined there).
         Node key names are not case-sensitive.
         
         The value for a key will be available from the `Node`_ object as
         attribute ``<prefix>_<key>`` (e.g., ``node.myplugin_mykey``). If not
         set, the attribute will be set to an empty string.
         
         This method can be overridden by derived classes. The implementation
         must not call the parent class' implementation. The default
         implementation returns an empty list.

     .. _Plugin.options:

     **options** (self)

         Returns a set of local configuration options provided by the
         plugin.
         
         The return value is a list of 4-tuples each having the following
         elements:
         
             ``name``
                 A string with name of the option (e.g., ``Path``). Option
                 names are not case-sensitive. Note that the option name exposed
                 to the user will be prefixed with your plugin's prefix as
                 returned by *prefix()* (e.g., ``myplugin.Path``).
         
             ``type``
                 A string with type of the option, which must be one of
                 ``"bool"``, ``"string"``, or ``"int"``.
         
             ``default``
                 The option's default value.  Note that this value must be
                 enclosed in quotes if the type is "string", and must not be
                 enclosed in quotes if the type is not "string".
         
             ``description``
                 A string with a description of the option semantics.
         
         This method can be overridden by derived classes. The implementation
         must not call the parent class' implementation. The default
         implementation returns an empty list.

     .. _Plugin.pluginVersion:

     **pluginVersion** (self)

         Returns an integer with a version number for the plugin. Plugins
         should increase their version number with any significant change.
         
         This method must be overridden by derived classes. The implementation
         must not call the parent class' implementation.

     .. _Plugin.prefix:

     **prefix** (self)

         Returns a string with a prefix for the plugin's options and
         commands names (e.g., "myplugin").  The prefix cannot contain
         any whitespace or dots (because dots are used as separators when
         forming the plugin's option names, state variable names, and
         command names).
         
         Note that ZeekControl will refuse to load a plugin if its prefix
         matches the prefix of another loaded plugin (this comparison is not
         case-sensitive).
         
         This method can be overridden by derived classes. The implementation
         must not call the parent class' implementation. The default
         implementation returns a lower-cased version of *name()*.

     .. _Plugin.zeekProcessDied:

     **zeekProcessDied** (self, node)

         Called when ZeekControl finds the Zeek process for Node_ *node*
         to have terminated unexpectedly. This method will be called just
         before ZeekControl prepares the node's "crash report" and before it
         cleans up the node's spool directory.
         
         This method can be overridden by derived classes. The default
         implementation does nothing.

     .. _Plugin.zeekctl_config:

     **zeekctl_config** (self)

         Returns a string containing Zeek script code that should be written
         to the dynamically generated Zeek script named "zeekctl-config.zeek".
         This provides a way for plugins to easily add Zeek script code that
         depends on zeekctl settings.
         
         This method can be overridden by derived classes. The default
         implementation does nothing.

.. _Node:

Class ``Node``
~~~~~~~~~~~~~~

class **Node**
     Class representing one node of the ZeekControl maintained setup. In
     standalone mode, there's always exactly one node of type ``standalone``. In
     a cluster setup, there is zero or more of type ``logger``, exactly one of
     type ``manager``, one or more of type ``proxy``, and zero or more of type
     ``worker``.  The manager will handle writing logs if there are no loggers
     defined in a cluster.
     
     A ``Node`` object has a number of keys with values that are set via the
     ``node.cfg`` file and can be accessed directly (from a plugin) via
     corresponding Python attributes (e.g., ``node.name``):
     
         ``name`` (string)
             The name of the node, which corresponds to the ``[<name>]``
             section in ``node.cfg``.
     
         ``type`` (string)
             The type of the node.  In a standalone configuration, the only
             allowed type is ``standalone``.  In a cluster configuration, the
             type must be one of: ``logger``, ``manager``, ``proxy``,
             or ``worker``.
     
         ``host`` (string)
             The hostname or IP address of the system the node is
             running on.  Every node must specify a host.
     
         ``interface`` (string)
             The network interface for the Zeek worker (or standalone node) to
             use; empty if not set.
     
         ``lb_procs`` (integer)
             The number of clustered Zeek workers you'd like to start up.  If
             specified, this number must be greater than zero and a load
             balancing method must also be specified.  This option is valid only
             for worker nodes.
     
         ``lb_method`` (string)
             The load balancing method to distribute packets to all of the
             Zeek workers.  This must be one of: ``pf_ring``, ``myricom``,
             ``custom``, or ``interfaces``.  This option can have a value
             only if the ``lb_procs`` option has a value.
     
         ``lb_interfaces`` (string)
             A comma-separated list of network interface names for the Zeek
             worker to use.  The number of interfaces in this list must
             equal the value of the ``lb_procs`` option.
     
             This option can be specified only when the load balancing method
             is ``interfaces``.
     
         ``pin_cpus`` (string)
             A comma-separated list of CPU numbers to which the node's Zeek
             processes will be pinned.  If not specified, then CPU pinning will
             not be used for this node.  This option is supported only on
             Linux and FreeBSD, and is ignored on all other platforms.
     
             CPU numbering starts at zero (e.g.,
             the only valid CPU numbers for a machine with one dual-core
             processor would be 0 and 1).  If the length of this list does not
             match the number of Zeek processes for this node, then some CPUs
             could have zero (if too many CPU numbers are specified) or more
             than one (if not enough CPU numbers are specified) Zeek processes
             pinned to them.  Only the specified CPU numbers will be used,
             regardless of whether additional CPU cores exist.
     
         ``env_vars`` (string)
             A comma-separated list of environment variables to set when
             running Zeek (e.g., ``env_vars=VAR1=1,VAR2=2``).  These
             node-specific values override any global values specified in
             the ``zeekctl.cfg`` file.
     
         ``aux_scripts`` (string)
             Any node-specific Zeek script configured for this node.
     
         ``zone_id`` (string)
             If ZeekControl is managing a cluster comprised of nodes
             using non-global IPv6 addresses, then this configures the
             :rfc:`4007` ``zone_id`` string that the node associates with
             the common zone that all cluster nodes are a part of.  This
             identifier may differ between nodes.
     
     Any attribute that is not defined in ``node.cfg`` will be empty.
     
     In addition, plugins can override `Plugin.nodeKeys`_ to define their own
     node keys, which can then be likewise set in ``node.cfg``. The key names
     will be prepended with the plugin's `Plugin.prefix`_ (e.g., for the plugin
     ``test``, the node key ``foo`` is set by adding ``test.foo=value`` to
     ``node.cfg``).
     
     Finally, a Node object has the following methods that can be called
     from a plugin:

     .. _Node.cwd:

     **cwd** (self)

         Returns a string with the node's working directory.

     .. _Node.describe:

     **describe** (self)

         Returns an extended string representation of the node including all
         its keys with values (sorted by key).

     .. _Node.getPID:

     **getPID** (self)

         Returns the process ID of the node's Zeek process if running, and
         None otherwise.

     .. _Node.getPort:

     **getPort** (self)

         Returns an integer with the port number that this node's
         communication system is listening on for incoming connections, or -1 if
         no such port has been set yet.

     .. _Node.hasCrashed:

     **hasCrashed** (self)

         Returns True if the node's Zeek process has exited abnormally.


.. _FAQ:

Questions and Answers
---------------------

*Can I use an NFS-mounted partition as the cluster's base directory to avoid the ``rsync``'ing?*
    Yes. ZeekBase_ can be on an NFS partition.
    Configure and install the shell as usual with
    ``--prefix=<ZeekBase>``. Then add ``HaveNFS=1`` and
    ``SpoolDir=<spath>`` to ``zeekctl.cfg``, where ``<spath>`` is a
    path on the local disks of the nodes; ``<spath>`` will be used for
    all non-shared data (make sure that the parent directory exists
    and is writable on all nodes!). Then run ``make install`` again.
    Finally, you can remove ``<ZeekBase>/spool`` (or link it to <spath>).
    In addition, you might want to keep the log files locally on the nodes
    as well by setting LogDir_ to a non-NFS directory. (Only
    the manager's logs will be kept permanently, the logs of
    workers/proxies are discarded upon rotation.)

*What do I need to do when something in the Zeek distribution changes?*
    After pulling from the main Zeek git repository, just re-run ``make
    install`` inside your build directory.  It will reinstall all the
    files from the distribution that are not up-to-date. Then do
    ``zeekctl deploy`` to make sure everything gets pushed out.

*Can I change the naming scheme that ZeekControl uses for archived log files?*
    Yes, set MakeArchiveName_ to a
    script that outputs the desired destination file name for an
    archived log file. The default script for that task is
    ``<ZeekBase>/share/zeekctl/scripts/make-archive-name``, which you
    can use as a template for creating your own version. See
    the beginning of that script for instructions.

*Can ZeekControl manage a cluster of nodes over non-global IPv6 scope (e.g. link-local)?*
    This used to be supported through a ``ZoneID`` option in
    ``zeekctl.cfg``, but no longer works in later versions
    of Zeek which use Broker as the communication framework. Please
    file a feature request if this is important to you.
