This is the command onnode that can be run in the OnWorks free hosting provider using one of our multiple free online workstations such as Ubuntu Online, Fedora Online, Windows online emulator or MAC OS online emulator
PROGRAM:
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 environment variable. 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.
lvs | lvsmaster
The current LVS master.
natgw | natgwlist
The current NAT gateway.
rm | recmaster
The current recovery master.
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/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.
Use onnode online using onworks.net services
