January 7, 2001 DVT 1

### NAME

dvt - launch an interactive window on a cluster of machines

### SYNOPSIS

dvt [-eiqv] [-f fanout] [-g rungroup1,...,rungroupN] [-l username] [-w node1,...,nodeN] [-x node1,...,nodeN]

### DESCRIPTION

The dvt utility launches a number of terminal windows, one for each machine the user specifies on the command line. In addition, it launches a single control window. The terminal windows are similar to terminal windows provided by xterm(1), xvt(1) or rxvt(1) in most regards, and may be used as a standard terminal window by themselves. The control window however, allows global control of all the terminal windows. The user can type in the command box of the control window, and the keystrokes will be sent to all the terminal windows at once. In this way the user can perform interactive commands, such as editing a file, in parallel. At any point, the user can switch his keyboard focus to a particular window, and issue commands to that window only, should it become neccesary. The following options are available:

-e
  Unless the -e option is specified, stderr from remote commands will not be reported to the user.

-i
  The -i option will list information about the current cluster, and command groupings. It will print out the current value of the fanout, and how many groups of machines there are within the cluster. It will also show you which command you are about to run, and your username if specified with the -l option.

-q
  The -q option does not issue any commands, but displays information about the cluster, and the fanout groupings.

-v
  Prints the version of ClusterIt to the stdout, and exits.

-f
  If the -f option is specified, followed by a number, it sets the fanout size of the cluster. The fanout size is the number of nodes a command will run on in parallel at one time. The fanout option, restricts the maximum number of windows that can be opened at one time. This is used to prevent the user from accidentally launching hundreds of windows, and crashing their X-terminal, or server. The fanout size defaults to 64. This option overrides the ```FANOUT` environment variable.

-g
  If the -g option is specified, followed by a comma separated list of group names, the command will only be run on that group of nodes. A node may be a part of more than one group if desired, however running without the -g option will open windows to the same node as many times as it appears in the file specified by the ```CLUSTER` environment variable. This option is silently ignored if used with the -w option.

-l
  If the -l option is specified, followed by a username, the initial connection attempted will pass the username argument and attempt to login with that account to the remote system. Consideration must be taken for proper authentication, for this to work.

-w
  If the -w option is specified, followed by a comma delimited list of machine names, windows will be opened to each node in the list. Without this option, dvt open windows to all the nodes listed in the file pointed to by the ```CLUSTER` environment variable.

-x
  The -x option can be used to exclude specific nodes from the cluster. The format is the same as the -w option, a comma delimited list of machine names. This option is silently ignored if used with the -w option.

### ENVIRONMENT

dvt utilizes the following environment variables.

```CLUSTER`
  Contains a filename, which is a newline separated list of nodes in the cluster.

```RVT_CMD`
  Contains the name of a binary to be executed by dvt which will open a terminal window and connection to a single remote host. The user may override this with another program that performs the same function, however, the program must supply as it's only output to stdout, it's X Window-ID in decimal. In addition, it must take as the final argument, the name of a remtoe machine to connect to. This program must also be capable of recieving X events sent via the XSendEvent(3) facility. If this environment variable is not set, it defaults to rvt

```RVT_CMD_ARGS`
  Contains any additional arguments that you wish to pass to the rvt command. This can be used to set things like colors, reverse video, etc in the terminal windows.

```FANOUT`
  When set, limits the maximum number of terminal windows to open simultaneously. This is designed to safeguard the user from potentially opening hundreds of windows, and overloading the X-terminal or server. Defaults to 64. This environment setting can be overridden by the -f option.

### FILES

The file pointed to by the ```CLUSTER` environment variable has the following format:

  `

      pollux
      castor
      GROUP:alpha
      rigel
      kent
      GROUP:sparc
      alshain
      altair
      LUMP:alphasparc
      alpha
      sparc

  `

This example would have pollux and castor a member of no groups, rigel and kent a member of group 'alpha', and alshain and altair a member of group `sparc'. Note the format of the GROUP command, it is in all capital letters, followed by a colon, and the group name. There can be no spaces following the GROUP command, or in the name of the group.

There is also a LUMP command, which is identical in syntax to the GROUP command. This command allows you to create a named group of groups. Each member of the lump is the name of a group. The LUMP command is terminated by another LUMP or GROUP command, or the EOF marker.

Any line beginning with a `#' symbol denotes a comment field, and the entire line will be ignored. Note that a hash mark placed anywhere other than the first character of a line, will be considered part of a valid hostname or command.

### DIAGNOSTICS

Exit status is 0 on success, 1 if an error occurs.

### SEE ALSO

xterm(1), dsh(1), rvt(1), XSendEvent(3), kerberos(3), hosts.equiv(5), rhosts(5)

### HISTORY

The dvt command appeared in clusterit 2.0.

### AUTHOR

Dvt was written by Tim Rightnour.

### BUGS

Solaris 2.5.1 has a maximum of 256 open file descriptors. This means that dvt will fail on a fanout size greater than about 32-40 nodes.