Advanced Configuration
----------------------

.. Convert_to_RST:
   
   [[s-recurring-start]]
   == Specifying When Recurring Actions are Performed ==
   
   
   By default, recurring actions are scheduled relative to when the
   resource started.  So if your resource was last started at 14:32 and
   you have a backup set to be performed every 24 hours, then the backup
   will always run in the middle of the business day -- hardly
   desirable.
   
   To specify a date and time that the operation should be relative to, set
   the operation's +interval-origin+.  The cluster uses this point to
   calculate the correct +start-delay+ such that the operation will occur
   at _origin + (interval * N)_.
   
   So, if the operation's interval is 24h, its interval-origin is set to
   02:00 and it is currently 14:32, then the cluster would initiate
   the operation with a start delay of 11 hours and 28 minutes.  If the
   resource is moved to another node before 2am, then the operation is
   cancelled.
   
   The value specified for +interval+ and +interval-origin+ can be any
   date/time conforming to the
   http://en.wikipedia.org/wiki/ISO_8601[ISO8601 standard].  By way of
   example, to specify an operation that would run on the first Monday of
   2009 and every Monday after that, you would add:
   
   .Specifying a Base for Recurring Action Intervals
   =====
   [source,XML]
   <op id="my-weekly-action" name="custom-action" interval="P7D" interval-origin="2009-W01-1"/> 
   =====


.. _failure-handling:

Handling Resource Failure
#########################


.. Convert_to_RST_2:
   
   By default, Pacemaker will attempt to recover failed resources by restarting
   them. However, failure recovery is highly configurable.
   
   === Failure Counts ===
   
   Pacemaker tracks resource failures for each combination of node, resource, and
   operation (start, stop, monitor, etc.).
   
   You can query the fail count for a particular node, resource, and/or operation
   using the `crm_failcount` command. For example, to see how many times the
   10-second monitor for +myrsc+ has failed on +node1+, run:
   
   ----
   # crm_failcount --query -r myrsc -N node1 -n monitor -I 10s
   ----
   
   If you omit the node, `crm_failcount` will use the local node. If you omit the
   operation and interval, `crm_failcount` will display the sum of the fail counts
   for all operations on the resource.
   
   You can use `crm_resource --cleanup` or `crm_failcount --delete` to clear
   fail counts. For example, to clear the above monitor failures, run:
   
   ----
   # crm_resource --cleanup -r myrsc -N node1 -n monitor -I 10s
   ----
   
   If you omit the resource, `crm_resource --cleanup` will clear failures for all
   resources. If you omit the node, it will clear failures on all nodes. If you
   omit the operation and interval, it will clear the failures for all operations
   on the resource.
   
   [NOTE]
   ====
   Even when cleaning up only a single operation, all failed operations will
   disappear from the status display. This allows us to trigger a re-check of the
   resource's current status.
   ====
   
   Higher-level tools may provide other commands for querying and clearing
   fail counts.
   
   The `crm_mon` tool shows the current cluster status, including any failed
   operations. To see the current fail counts for any failed resources, call
   `crm_mon` with the `--failcounts` option. This shows the fail counts per
   resource (that is, the sum of any operation fail counts for the resource).
   
   === Failure Response ===
   
   Normally, if a running resource fails, pacemaker will try to stop it and start
   it again. Pacemaker will choose the best location to start it each time, which
   may be the same node that it failed on.
   
   However, if a resource fails repeatedly, it is possible that there is an
   underlying problem on that node, and you might desire trying a different node
   in such a case. Pacemaker allows you to set your preference via the
   +migration-threshold+ resource meta-attribute.
   footnote:[
   The naming of this option was perhaps unfortunate as it is easily
   confused with live migration, the process of moving a resource from
   one node to another without stopping it.  Xen virtual guests are the
   most common example of resources that can be migrated in this manner.
   ]
   
   If you define +migration-threshold=pass:[<replaceable>N</replaceable>]+ for a
   resource, it will be banned from the original node after 'N' failures.
   
   [NOTE]
   ====
   The +migration-threshold+ is per 'resource', even though fail counts are
   tracked per 'operation'. The operation fail counts are added together
   to compare against the +migration-threshold+.
   ====
   
   By default, fail counts remain until manually cleared by an administrator
   using `crm_resource --cleanup` or `crm_failcount --delete` (hopefully after
   first fixing the failure's cause). It is possible to have fail counts expire
   automatically by setting the +failure-timeout+ resource meta-attribute.
   
   [IMPORTANT]
   ====
   A successful operation does not clear past failures. If a recurring monitor
   operation fails once, succeeds many times, then fails again days later, its
   fail count is 2. Fail counts are cleared only by manual intervention or
   falure timeout.
   ====
   
   For example, a setting of +migration-threshold=2+ and +failure-timeout=60s+
   would cause the resource to move to a new node after 2 failures, and
   allow it to move back (depending on stickiness and constraint scores) after one
   minute.
   
   [NOTE]
   ====
   +failure-timeout+ is measured since the most recent failure. That is, older
   failures do not individually time out and lower the fail count. Instead, all
   failures are timed out simultaneously (and the fail count is reset to 0) if
   there is no new failure for the timeout period.
   ====
   
   There are two exceptions to the migration threshold concept:
   when a resource either fails to start or fails to stop.
   
   If the cluster property +start-failure-is-fatal+ is set to +true+ (which is the
   default), start failures cause the fail count to be set to +INFINITY+ and thus
   always cause the resource to move immediately.
   
   Stop failures are slightly different and crucial.  If a resource fails
   to stop and STONITH is enabled, then the cluster will fence the node
   in order to be able to start the resource elsewhere.  If STONITH is
   not enabled, then the cluster has no way to continue and will not try
   to start the resource elsewhere, but will try to stop it again after
   the failure timeout.
   
   == Moving Resources ==
   indexterm:[Moving,Resources] 
   indexterm:[Resource,Moving]
   
   === Moving Resources Manually ===
   
   There are primarily two occasions when you would want to move a
   resource from its current location: when the whole node is under
   maintenance, and when a single resource needs to be moved.
   
   ==== Standby Mode ====
   
   Since everything eventually comes down to a score, you could create
   constraints for every resource to prevent them from running on one
   node.  While pacemaker configuration can seem convoluted at times, not even
   we would require this of administrators.
   
   Instead, one can set a special node attribute which tells the cluster
   "don't let anything run here".  There is even a helpful tool to help
   query and set it, called `crm_standby`.  To check the standby status
   of the current machine, run:
   
   ----
   # crm_standby -G
   ----
   
   A value of +on+ indicates that the node is _not_ able to host any
   resources, while a value of +off+ says that it _can_.
   
   You can also check the status of other nodes in the cluster by
   specifying the `--node` option:
   
   ----
   # crm_standby -G --node sles-2
   ----
   
   To change the current node's standby status, use `-v` instead of `-G`:
   
   ----
   # crm_standby -v on
   ----
   
   Again, you can change another host's value by supplying a hostname with `--node`.
   
   A cluster node in standby mode will not run resources, but still contributes to
   quorum, and may fence or be fenced by nodes.
   
   ==== Moving One Resource ====
   
   When only one resource is required to move, we could do this by creating
   location constraints.  However, once again we provide a user-friendly
   shortcut as part of the `crm_resource` command, which creates and
   modifies the extra constraints for you.  If +Email+ were running on
   +sles-1+ and you wanted it moved to a specific location, the command
   would look something like:
           
   ----
   # crm_resource -M -r Email -H sles-2
   ----
   
   Behind the scenes, the tool will create the following location constraint:
   
   [source,XML]
   <rsc_location rsc="Email" node="sles-2" score="INFINITY"/>
   
   It is important to note that subsequent invocations of `crm_resource
   -M` are not cumulative. So, if you ran these commands
   
   ----
   # crm_resource -M -r Email -H sles-2
   # crm_resource -M -r Email -H sles-3
   ----
   
   then it is as if you had never performed the first command.
   
   To allow the resource to move back again, use:
   
   ----
   # crm_resource -U -r Email
   ----
   
   Note the use of the word _allow_.  The resource can move back to its
   original location but, depending on +resource-stickiness+, it might
   stay where it is.  To be absolutely certain that it moves back to
   +sles-1+, move it there before issuing the call to `crm_resource -U`:
           
   ----
   # crm_resource -M -r Email -H sles-1
   # crm_resource -U -r Email
   ----
   
   Alternatively, if you only care that the resource should be moved from
   its current location, try:
   
   ----
   # crm_resource -B -r Email
   ----
   
   Which will instead create a negative constraint, like
   
   [source,XML]
   <rsc_location rsc="Email" node="sles-1" score="-INFINITY"/>
   
   This will achieve the desired effect, but will also have long-term
   consequences.  As the tool will warn you, the creation of a
   +-INFINITY+ constraint will prevent the resource from running on that
   node until `crm_resource -U` is used.  This includes the situation
   where every other cluster node is no longer available!
   
   In some cases, such as when +resource-stickiness+ is set to
   +INFINITY+, it is possible that you will end up with the problem
   described in <<node-score-equal>>.  The tool can detect
   some of these cases and deals with them by creating both
   positive and negative constraints. E.g.
   
   +Email+ prefers +sles-1+ with a score of +-INFINITY+
   
   +Email+ prefers +sles-2+ with a score of +INFINITY+
   
   which has the same long-term consequences as discussed earlier.
   
   === Moving Resources Due to Connectivity Changes ===
   
   You can configure the cluster to move resources when external connectivity is
   lost in two steps.
   
   ==== Tell Pacemaker to Monitor Connectivity ====
   
   First, add an *ocf:pacemaker:ping* resource to the cluster.  The
   *ping* resource uses the system utility of the same name to a test whether
   list of machines (specified by DNS hostname or IPv4/IPv6 address) are
   reachable and uses the results to maintain a node attribute called +pingd+
   by default.
   footnote:[
   The attribute name is customizable, in order to allow multiple ping groups to be defined.
   ]
   
   [NOTE]
   ===========
   Older versions of Pacemaker used a different agent *ocf:pacemaker:pingd* which
   is now deprecated in favor of *ping*. If your version of Pacemaker does not
   contain the *ping* resource agent, download the latest version from
   https://github.com/ClusterLabs/pacemaker/tree/master/extra/resources/ping
   ===========
   
   Normally, the ping resource should run on all cluster nodes, which means that
   you'll need to create a clone.  A template for this can be found below
   along with a description of the most interesting parameters.
             
   .Common Options for a 'ping' Resource
   [width="95%",cols="1m,<4",options="header",align="center"]
   |=========================================================
   
   |Field
   |Description
   
   |dampen
   |The time to wait (dampening) for further changes to occur. Use this
    to prevent a resource from bouncing around the cluster when cluster
    nodes notice the loss of connectivity at slightly different times.
    indexterm:[dampen,Ping Resource Option]
    indexterm:[Ping Resource,Option,dampen]
   
   |multiplier
   |The number of connected ping nodes gets multiplied by this value to
    get a score. Useful when there are multiple ping nodes configured.
    indexterm:[multiplier,Ping Resource Option]
    indexterm:[Ping Resource,Option,multiplier]
   
   |host_list
   |The machines to contact in order to determine the current
    connectivity status. Allowed values include resolvable DNS host
    names, IPv4 and IPv6 addresses.
    indexterm:[host_list,Ping Resource Option]
    indexterm:[Ping Resource,Option,host_list]
   
   |=========================================================
   
   .An example ping cluster resource that checks node connectivity once every minute
   =====
   [source,XML]
   ------------
   <clone id="Connected">
      <primitive id="ping" provider="pacemaker" class="ocf" type="ping">
       <instance_attributes id="ping-attrs">
         <nvpair id="pingd-dampen" name="dampen" value="5s"/>
         <nvpair id="pingd-multiplier" name="multiplier" value="1000"/>
         <nvpair id="pingd-hosts" name="host_list" value="my.gateway.com www.bigcorp.com"/>
       </instance_attributes>
       <operations>
         <op id="ping-monitor-60s" interval="60s" name="monitor"/>
       </operations>
      </primitive>
   </clone>
   ------------
   =====
   
   [IMPORTANT]
   ===========
   You're only half done.  The next section deals with telling Pacemaker
   how to deal with the connectivity status that +ocf:pacemaker:ping+ is
   recording.
   ===========
   
   ==== Tell Pacemaker How to Interpret the Connectivity Data ====
   
   [IMPORTANT]
   ======
   Before attempting the following, make sure you understand
   <<ch-rules>>.
   ======
   
   There are a number of ways to use the connectivity data.
   
   The most common setup is for people to have a single ping
   target (e.g. the service network's default gateway), to prevent the cluster
   from running a resource on any unconnected node.
   
   .Don't run a resource on unconnected nodes
   =====
   [source,XML]
   -------
   <rsc_location id="WebServer-no-connectivity" rsc="Webserver">
      <rule id="ping-exclude-rule" score="-INFINITY" >
       <expression id="ping-exclude" attribute="pingd" operation="not_defined"/>
      </rule>
   </rsc_location>
   -------
   =====
   
   A more complex setup is to have a number of ping targets configured.
   You can require the cluster to only run resources on nodes that can
   connect to all (or a minimum subset) of them.
   
   .Run only on nodes connected to three or more ping targets.
   =====
   [source,XML]
   -------
   <primitive id="ping" provider="pacemaker" class="ocf" type="ping">
   ... <!-- omitting some configuration to highlight important parts -->
         <nvpair id="pingd-multiplier" name="multiplier" value="1000"/>
   ...
   </primitive>
   ...
   <rsc_location id="WebServer-connectivity" rsc="Webserver">
      <rule id="ping-prefer-rule" score="-INFINITY" >
         <expression id="ping-prefer" attribute="pingd" operation="lt" value="3000"/>
      </rule>
   </rsc_location>
   -------
   =====
   
   Alternatively, you can tell the cluster only to _prefer_ nodes with the best
   connectivity.  Just be sure to set +multiplier+ to a value higher than
   that of +resource-stickiness+ (and don't set either of them to
   +INFINITY+).
   
   .Prefer the node with the most connected ping nodes
   =====
   [source,XML]
   -------
   <rsc_location id="WebServer-connectivity" rsc="Webserver">
      <rule id="ping-prefer-rule" score-attribute="pingd" >
       <expression id="ping-prefer" attribute="pingd" operation="defined"/>
      </rule>
   </rsc_location>
   -------
   =====
   
   It is perhaps easier to think of this in terms of the simple
   constraints that the cluster translates it into.  For example, if
   *sles-1* is connected to all five ping nodes but *sles-2* is only
   connected to two, then it would be as if you instead had the following
   constraints in your configuration:
   
   .How the cluster translates the above location constraint
   =====
   [source,XML]
   -------
   <rsc_location id="ping-1" rsc="Webserver" node="sles-1" score="5000"/>
   <rsc_location id="ping-2" rsc="Webserver" node="sles-2" score="2000"/>
   -------
   =====
   
   The advantage is that you don't have to manually update any
   constraints whenever your network connectivity changes.
   
   You can also combine the concepts above into something even more
   complex.  The example below shows how you can prefer the node with the
   most connected ping nodes provided they have connectivity to at least
   three (again assuming that +multiplier+ is set to 1000).
   
   .A more complex example of choosing a location based on connectivity
   =====
   [source,XML]
   -------
   <rsc_location id="WebServer-connectivity" rsc="Webserver">
      <rule id="ping-exclude-rule" score="-INFINITY" >
       <expression id="ping-exclude" attribute="pingd" operation="lt" value="3000"/>
      </rule>
      <rule id="ping-prefer-rule" score-attribute="pingd" >
       <expression id="ping-prefer" attribute="pingd" operation="defined"/>
      </rule>
   </rsc_location>
   -------
   =====


.. _live-migration:

Migrating Resources
___________________


.. Convert_to_RST_3:
   
   Normally, when the cluster needs to move a resource, it fully restarts
   the resource (i.e. stops the resource on the current node
   and starts it on the new node).
   
   However, some types of resources, such as Xen virtual guests, are able to move to
   another location without loss of state (often referred to as live migration
   or hot migration). In pacemaker, this is called resource migration.
   Pacemaker can be configured to migrate a resource when moving it,
   rather than restarting it.
   
   Not all resources are able to migrate; see the Migration Checklist
   below, and those that can, won't do so in all situations.
   Conceptually, there are two requirements from which the other
   prerequisites follow:
   
   * The resource must be active and healthy at the old location; and
   * everything required for the resource to run must be available on
     both the old and new locations.
   
   The cluster is able to accommodate both 'push' and 'pull' migration models
   by requiring the resource agent to support two special actions:
   +migrate_to+ (performed on the current location) and +migrate_from+
   (performed on the destination).
   
   In push migration, the process on the current location transfers the
   resource to the new location where is it later activated.  In this
   scenario, most of the work would be done in the +migrate_to+ action
   and, if anything, the activation would occur during +migrate_from+.
   
   Conversely for pull, the +migrate_to+ action is practically empty and
   +migrate_from+ does most of the work, extracting the relevant resource
   state from the old location and activating it.
   
   There is no wrong or right way for a resource agent to implement migration,
   as long as it works.
   
   .Migration Checklist
   * The resource may not be a clone.
   * The resource must use an OCF style agent.
   * The resource must not be in a failed or degraded state.
   * The resource agent must support +migrate_to+ and
     +migrate_from+ actions, and advertise them in its metadata.
   * The resource must have the +allow-migrate+ meta-attribute set to
     +true+ (which is not the default).
   
   If an otherwise migratable resource depends on another resource
   via an ordering constraint, there are special situations in which it will be
   restarted rather than migrated.
   
   For example, if the resource depends on a clone, and at the time the resource
   needs to be moved, the clone has instances that are stopping and instances
   that are starting, then the resource will be restarted. The scheduler is not
   yet able to model this situation correctly and so takes the safer (if less
   optimal) path.
   
   Also, if a migratable resource depends on a non-migratable resource, and both
   need to be moved, the migratable resource will be restarted.


.. _node-health:

Tracking Node Health
####################
   
.. Convert_to_RST_4:
   
   A node may be functioning adequately as far as cluster membership is concerned,
   and yet be "unhealthy" in some respect that makes it an undesirable location
   for resources. For example, a disk drive may be reporting SMART errors, or the
   CPU may be highly loaded.
   
   Pacemaker offers a way to automatically move resources off unhealthy nodes.
   
   === Node Health Attributes ===
   
   Pacemaker will treat any node attribute whose name starts with +#health+ as an
   indicator of node health. Node health attributes may have one of the following
   values:
   
   .Allowed Values for Node Health Attributes
   [width="95%",cols="1,<3",options="header",align="center"]
   |=========================================================
   
   |Value
   |Intended significance
   
   |+red+
   |This indicator is unhealthy
    indexterm:[Node health,red]
   
   |+yellow+
   |This indicator is becoming unhealthy
    indexterm:[Node health,yellow]
   
   |+green+
   |This indicator is healthy
    indexterm:[Node health,green]
   
   |'integer'
   |A numeric score to apply to all resources on this node
    (0 or positive is healthy, negative is unhealthy)
    indexterm:[Node health,score]
   
   |=========================================================
   
   === Node Health Strategy ===
   
   Pacemaker assigns a node health score to each node, as the sum of the values of
   all its node health attributes. This score will be used as a location
   constraint applied to this node for all resources.
   
   The +node-health-strategy+ cluster option controls how Pacemaker responds to
   changes in node health attributes, and how it translates +red+, +yellow+, and
   +green+ to scores.
   
   Allowed values are:
   
   .Node Health Strategies
   [width="95%",cols="1m,<3",options="header",align="center"]
   |=========================================================
   
   |Value
   |Effect
   
   |none
   |Do not track node health attributes at all.
    indexterm:[Node health,none]
   
   |migrate-on-red
   |Assign the value of +-INFINITY+ to +red+, and 0 to +yellow+ and +green+.
    This will cause all resources to move off the node if any attribute is +red+.
    indexterm:[Node health,migrate-on-red]
   
   |only-green
   |Assign the value of +-INFINITY+ to +red+ and +yellow+, and 0 to +green+.
    This will cause all resources to move off the node if any attribute is +red+
    or +yellow+.
    indexterm:[Node health,only-green]
   
   |progressive
   |Assign the value of the +node-health-red+ cluster option to +red+, the value
    of +node-health-yellow+ to +yellow+, and the value of +node-health-green+ to
    +green+. Each node is additionally assigned a score of +node-health-base+
    (this allows resources to start even if some attributes are +yellow+). This
    strategy gives the administrator finer control over how important each value
    is.
    indexterm:[Node health,progressive]
   
   |custom
   |Track node health attributes using the same values as +progressive+ for
    +red+, +yellow+, and +green+, but do not take them into account.
    The administrator is expected to implement a policy by defining rules
    (see <<ch-rules>>) referencing node health attributes.
    indexterm:[Node health,custom]
   
   |=========================================================
   
   === Measuring Node Health ===
   
   Since Pacemaker calculates node health based on node attributes,
   any method that sets node attributes may be used to measure node
   health. The most common ways are resource agents or separate daemons.
   
   Pacemaker provides examples that can be used directly or as a basis for
   custom code. The +ocf:pacemaker:HealthCPU+ and +ocf:pacemaker:HealthSMART+
   resource agents set node health attributes based on CPU and disk parameters.
   The +ipmiservicelogd+ daemon sets node health attributes based on IPMI
   values (the +ocf:pacemaker:SystemHealth+ resource agent can be used to manage
   the daemon as a cluster resource).
   
   In order to take advantage of this feature - firstly add the resource to your cluster, preferably as a cloned resource to constantly measure health on all nodes:
   
   =====
   [source,XML]
   ------------
   <clone id="resHealthIOWait-clone">
     <primitive class="ocf" id="HealthIOWait" provider="pacemaker" type="HealthIOWait">
       <instance_attributes id="resHealthIOWait-instance_attributes">
         <nvpair id="resHealthIOWait-instance_attributes-red_limit" name="red_limit" value="30"/>
         <nvpair id="resHealthIOWait-instance_attributes-yellow_limit" name="yellow_limit" value="10"/>
       </instance_attributes>
       <operations>
         <op id="resHealthIOWait-monitor-interval-5" interval="5" name="monitor" timeout="5"/>
         <op id="resHealthIOWait-start-interval-0s" interval="0s" name="start" timeout="10s"/>
         <op id="resHealthIOWait-stop-interval-0s" interval="0s" name="stop" timeout="10s"/>
       </operations>
     </primitive>
   </clone>
   ------------
   =====
   
   This way attrd_updater will set proper status for each node running this resource. Any attribute matching "#health-[a-zA-z]+" will force cluster to migrate all resources from unhealthy node and place it on other nodes according to all constraints defined in your cluster.
   
   When the node is no longer faulty you can force the cluster to restart the cloned resource on faulty node and make it available to take resources, in this case since we are using HealthIOWait provider:
   
   ----
   # attrd_updater -n "#health-iowait" -U "green" --node="<nodename>" -d "60s"
   ----
   
   == Reloading Services After a Definition Change ==
   
   The cluster automatically detects changes to the definition of
   services it manages.  The normal response is to stop the
   service (using the old definition) and start it again (with the new
   definition).  This works well, but some services are smarter and can
   be told to use a new set of options without restarting.
   
   To take advantage of this capability, the resource agent must:
   
   . Accept the +reload+ operation and perform any required actions.
     _The actions here depend completely on your application!_
   +
   .The DRBD agent's logic for supporting +reload+
   =====
   [source,Bash]
   -------
   case $1 in
       start)
           drbd_start
           ;;
       stop)
           drbd_stop
           ;;
       reload)
           drbd_reload
           ;;
       monitor)
           drbd_monitor
           ;;
       *)
           drbd_usage
           exit $OCF_ERR_UNIMPLEMENTED
           ;;
   esac
   exit $?
   -------
   =====
   . Advertise the +reload+ operation in the +actions+ section of its metadata
   +
   .The DRBD Agent Advertising Support for the +reload+ Operation
   =====
   [source,XML]
   -------
   <?xml version="1.0"?>
     <!DOCTYPE resource-agent SYSTEM "ra-api-1.dtd">
     <resource-agent name="drbd">
       <version>1.1</version>
       
       <longdesc lang="en">
         Master/Slave OCF Resource Agent for DRBD
       </longdesc>
       
       ...
       
       <actions>
         <action name="start"   timeout="240" />
         <action name="reload"  timeout="240" />
         <action name="promote" timeout="90" />
         <action name="demote"  timeout="90" />
         <action name="notify"  timeout="90" />
         <action name="stop"    timeout="100" />
         <action name="meta-data"    timeout="5" />
         <action name="validate-all" timeout="30" />
       </actions>
     </resource-agent>
   -------
   =====
   . Advertise one or more parameters that can take effect using +reload+.
   +
   Any parameter with the +unique+ set to 0 is eligible to be used in this way.
   +
   .Parameter that can be changed using reload
   =====
   [source,XML]
   -------
   <parameter name="drbdconf" unique="0">
       <longdesc lang="en">Full path to the drbd.conf file.</longdesc>
       <shortdesc lang="en">Path to drbd.conf</shortdesc>
       <content type="string" default="${OCF_RESKEY_drbdconf_default}"/>
   </parameter>
   -------
   =====
   
   Once these requirements are satisfied, the cluster will automatically
   know to reload the resource (instead of restarting) when a non-unique
   field changes.
         
   [NOTE]
   ======
   Metadata will not be re-read unless the resource needs to be started. This may
   mean that the resource will be restarted the first time, even though you
   changed a parameter with +unique=0+.
   ======
   
   [NOTE]
   ======
   If both a unique and non-unique field are changed simultaneously, the
   resource will still be restarted.
   ======
