NAME

       onnode - run commands on CTDB cluster nodes

SYNOPSIS

       onnode [OPTION...] {NODES} {COMMAND}

DESCRIPTION

       onnode is a utility to run commands on a specific node of a CTDB cluster, or on all nodes.

       NODES specifies which node(s) to run a command on. See section NODES SPECIFICATION for
       details.

       COMMAND can be any shell command. The onnode utility uses ssh or rsh to connect to the
       remote nodes and run the command.

OPTIONS

       -c
           Execute COMMAND in the current working directory on the specified nodes.

       -f FILENAME
           Specify an alternative nodes FILENAME to use instead of the default. This option
           overrides the CTDB_NODES_FILE and CTDB_NODES variables. See the discussion of
           /etc/ctdb/nodes in the FILES section for more details.

       -i
           Keep standard input open, allowing data to be piped to onnode. Normally onnode closes
           stdin to avoid surprises when scripting. Note that this option is ignored when using
           -p or if SSH is set to anything other than "ssh".

       -n
           Allow nodes to be specified by name rather than node numbers. These nodes don't need
           to be listed in the nodes file. You can avoid the nodes file entirely by combining
           this with -f /dev/null.

       -o PREFIX
           Causes standard output from each node to be saved into a file with name PREFIX.IP.

       -p
           Run COMMAND in parallel on the specified nodes. The default is to run COMMAND
           sequentially on each node.

       -P
           Push files to nodes. Names of files to push are specified rather than the usual
           command. Quoting is fragile/broken - filenames with whitespace in them are not
           supported.

       -q
           Do not print node addresses. Normally, onnode prints informational node addresses if
           more than one node is specified. This overrides -v.

       -v
           Print node addresses even if only one node is specified. Normally, onnode prints
           informational node addresses when more than one node is specified.

       -h, --help
           Show a short usage guide.

NODES SPECIFICATION

       Nodes can be specified via numeric node numbers (from 0 to N-1) or mnemonics. Multiple
       nodes are specified using lists of nodes, separated by commas, and ranges of numeric node
       numbers, separated by dashes. If nodes are specified multiple times then the command will
       be executed multiple times on those nodes. The order of nodes is significant.

       The following mnemonics are available:

       all
           All nodes.

       any
           A node where ctdbd is running. This semi-random but there is a bias towards choosing a
           low numbered node.

       ok | healthy
           All nodes that are not disconnected, banned, disabled or unhealthy.

       con | connected
           All nodes that are not disconnected.

EXAMPLES

       The following command would show the process ID of ctdbd on all nodes

                 onnode all ctdb getpid

       The following command would show the last 5 lines of log on each node, preceded by the
       node's hostname

                 onnode all "hostname; tail -5 /var/log/ctdb/log.ctdb"

       The following command would restart the ctdb service on all nodes, in parallel.

                 onnode -p all service ctdb restart

       The following command would run ./foo in the current working directory, in parallel, on
       nodes 0, 2, 3 and 4.

                 onnode -c -p 0,2-4 ./foo

ENVIRONMENT

       CTDB_BASE
           Directory containing CTDB configuration files. The default is /etc/ctdb.

       CTDB_NODES_FILE
           Name of alternative nodes file to use instead of the default. See the FILES section
           for more details.

FILES

       /etc/ctdb/nodes
           Default file containing a list of each node's IP address or hostname.

           As above, a file specified via the -f or CTDB_NODES_FILE is given precedence. If a
           relative path is specified and no corresponding file exists relative to the current
           directory then the file is also searched for in the $CTDB_BASE directory.

           If CTDB_NODES_FILE is not set and CTDB_NODES is set in configuration then the file
           pointed to by CTDB_NODES is used.

           Otherwise the default is $CTDB_BASE/nodes, where CTDB_BASE defaults to /etc/ctdb.

       /etc/ctdb/onnode.conf
           If this file exists it is sourced by onnode. The main purpose is to allow the
           administrator to set SSH to something other than "ssh". In this case the -t option is
           ignored. For example, the administrator may choose to use use rsh instead of ssh.

SEE ALSO

       ctdb(7), http://ctdb.samba.org/

AUTHOR

       This documentation was written by Andrew Tridgell, Martin Schwenke

COPYRIGHT

       Copyright © 2007 Andrew Tridgell, Ronnie Sahlberg
       Copyright © 2008 Martin Schwenke

       This program is free software; you can redistribute it and/or modify it under the terms of
       the GNU General Public License as published by the Free Software Foundation; either
       version 3 of the License, or (at your option) any later version.

       This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
       without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
       See the GNU General Public License for more details.

       You should have received a copy of the GNU General Public License along with this program;
       if not, see http://www.gnu.org/licenses.