onnode - run commands on CTDB cluster nodes

       This documentation was written by Andrew Tridgell, Martin Schwenke

       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.

ctdb                                               06/19/2025                                          ONNODE(1)

       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.

       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

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

           As above, a file specified via the -f 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 configuration directory.

           Otherwise the default is /etc/ctdb/nodes.

       /etc/ctdb/onnode.conf
           If this file exists it is sourced by onnode. The main purpose is to allow the administrator to set
           ONNODE_SSH to something other than "ssh". In this case the -t option is ignored.

       onnode - run commands on CTDB cluster nodes

       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.

       -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. 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 ONNODE_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.

       -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.

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

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