table of contents
| CLUSH(1) | ClusterShell User Manual | CLUSH(1) |
NAME¶
clush - execute shell commands on a clusterSYNOPSIS¶
clush -a | -g group | -w nodes [OPTIONS] clush -a | -g group | -w nodes [OPTIONS] command clush -a | -g group | -w nodes [OPTIONS] --copy file | dir [ file | dir ...] [ --dest path ] clush -a | -g group | -w nodes [OPTIONS] --rcopy file | dir [ file | dir ...] [ --dest path ]DESCRIPTION¶
clush is a program for executing commands in parallel on a cluster and for gathering their results. clush executes commands interactively or can be used within shell scripts and other applications. It is a partial front-end to the ClusterShell library that ensures a light, unified and robust parallel command execution framework. Thus, it allows traditional shell scripts to benefit from some of the library features. clush currently makes use of the Ssh worker of ClusterShell that only requires ssh(1) (OpenSSH SSH client).INVOCATION¶
clush can be started non-interactively to run a shell command, or can be invoked as an interactive shell. To start a clush interactive session, invoke the clush command without providing command.- Non-interactive mode
- When clush is started non-interactively, the command is executed on the specified remote hosts in parallel. If option -b or --dshbak is specified, clush waits for command completion and then displays gathered output results. The -w option allows you to specify remote hosts by using ClusterShell NodeSet syntax, including the node groups @group special syntax and the Extended Patterns syntax to benefits from NodeSet basic arithmetics (like @Agroup\&@Bgroup). See EXTENDED PATTERNS in nodeset(1) and also groups.conf(5) for more information. Unless option --nostdin is specified, clush detects when its standard input is connected to a terminal (as determined by isatty(3)). If actually connected to a terminal, clush listens to standard input when commands are running, waiting for an Enter key press. Doing so will display the status of current nodes. If standard input is not connected to a terminal, and unless option --nostdin is specified, clush binds the standard input of the remote commands to its own standard input, allowing scripting methods like:
# echo foo | clush -w node[40-42] -b cat --------------- node[40-42] --------------- foo
Please see some other great examples in the EXAMPLES section below.
- Interactive session
- If a command is not specified, and its standard input is connected to a terminal, clush runs interactively. In this mode, clush uses the GNU readline library to read command lines. Readline provides commands for searching through the command history for lines containing a specified string. For instance, type Control-R to search in the history for the next entry matching the search string typed so far. clush also recognizes special single-character prefixes that allows the user to see and modify the current nodeset (the nodes where the commands are executed).
- Single-character interactive commands are:
- clush> ?
- show current nodeset
- clush> =<NODESET>
- set current nodeset
- clush> +<NODESET>
- add nodes to current nodeset
- clush> -<NODESET>
- remove nodes from current nodeset
- clush> !COMMAND
- execute COMMAND on the local system
- clush> =
- toggle the output format (gathered or standard mode)
To leave an interactive session, type quit or Control-D.
- File copying mode ( --copy )
- When clush is started with the -c or --copy option, it will attempt to copy specified file and/or dir to the provided target cluster nodes. If the --dest option is specified, it will put the copied files there.
- Reverse file copying mode ( --rcopy )
- When clush is started with the --rcopy option, it will attempt to retrieve specified file and/or dir from provided cluster nodes. If the --dest option is specified, it must be a directory path where the files will be stored with their hostname appended. If the destination path is not specified, it will take the first file or dir basename directory as the local destination.
OPTIONS¶
- --version
- show clush version number and exit
- -s GROUPSOURCE, --groupsource=GROUPSOURCE
- optional groups.conf(5) group source to use
- --nostdin
- do not watch for possible input from stdin
- Selecting target nodes:
- -w NODES
- nodes where to run the command
- -x NODES
- exclude nodes from the node list
- -a, --all
- run command on all nodes
- -g GROUP, --group=GROUP
- run command on a group of nodes
- -X GROUP
- exclude nodes from this group
- Output behaviour:
- -q, --quiet
- be quiet, print essential output only
- -v, --verbose
- be verbose, print informative messages
- -d, --debug
- output more messages for debugging purpose
- -G, --groupbase
- do not display group source prefix
- -L
- disable header block and order output by nodes; additionally, when used in conjunction with -b/-B, it will enable "life gathering" of results by line mode, such as the next line is displayed as soon as possible (eg. when all nodes have sent the line)
- -N
- disable labeling of command line
- -b, --dshbak
- display gathered results in a dshbak-like way
- -B
- like -b but including standard error
- -r, --regroup
- fold nodeset using node groups
- -S
- return the largest of command return codes
- --color=WHENCOLOR
- whether to use ANSI colors to surround node or nodeset prefix/header with escape sequences to display them in color on the terminal. WHENCOLOR is never, always or auto (which use color if standard output/error refer to a terminal). Colors are set to [34m (blue foreground text) for stdout and [31m (red foreground text) for stderr, and cannot be modified.
- --diff
- show diff between common outputs (find the best reference output by focusing on largest nodeset and also smaller command return code)
- File copying:
- -c, --copy
- copy local file or directory to remote nodes
- --rcopy
- copy file or directory from remote nodes
- --dest=DEST_PATH
- destination file or directory on the nodes (optional: use the first source directory path when not specified)
- -p
- preserve modification times and modes
- Ssh options:
- -f FANOUT, --fanout=FANOUT
- use a specified maximum fanout size (ie. do not execute more than FANOUT commands at the same time, useful to limit resource usage)
- -l USER, --user=USER
- execute remote command as user
- -o OPTIONS, --options=OPTIONS
- can be used to give ssh options, eg. -o "-oPort=2022"
- -t CONNECT_TIMEOUT, --connect_timeout=CONNECT_TIMEOUT
- limit time to connect to a node
- -u COMMAND_TIMEOUT, --command_timeout=COMMAND_TIMEOUT
- limit time for command to run on the node
For a short explanation of these options, see -h, --help.
EXIT STATUS¶
By default, an exit status of zero indicates success of the clush command but gives no information about the remote commands exit status. However, when the -S option is specified, the exit status of clush is the largest value of the remote commands return codes. For failed remote commands whose exit status is non-zero, and unless the combination of options -qS is specified, clush displays messages similar to:- clush: node[40-42]: exited with exit code 1
EXAMPLES¶
Basic¶
- # clush -w node[3-5,62] uname -r
- Run command uname -r in parallel on nodes: node3, node4, node5 and node62
Display features¶
- # clush -w node[3-5,62] -b uname -r
- Run command uname -r on nodes[3-5,62] and display gathered output results (integrated dshbak-like).
- # clush -w node[3-5,62] -bL uname -r
- Line mode: run command uname -r on nodes[3-5,62] and display gathered output results without default header block.
- # ssh node32 find /etc/yum.repos.d -type f | clush -w node[40-42] -b xargs ls -l
- Search some files on node32 in /etc/yum.repos.d and use clush to list the matching ones on node[40-42], and use -b to display gathered results.
- # clush -w node[3-5,62] --diff dmidecode -s bios-version
- Run this Linux command to get BIOS version on nodes[3-5,62] and show version differences (if any).
All nodes¶
- # clush -a uname -r
- Run command uname -r on all cluster nodes, see groups.conf(5) to setup all cluster nodes ( all: field).
- # clush -a -x node[5,7] uname -r
- Run command uname -r on all cluster nodes except on nodes node5 and node7.
- # clush -a --diff cat /some/file
- Run command cat /some/file on all cluster nodes and show differences (if any), line by line, between common outputs.
Node groups¶
- # clush -w @oss modprobe lustre
- Run command modprobe lustre on nodes from node group named oss, see groups.conf(5) to setup node groups ( map: field).
- # clush -g oss modprobe lustre
- Same as previous example but using -g to avoid @ group prefix.
- # clush -w @mds,@oss modprobe lustre
- You may specify several node groups by separating them with commas (please see EXTENDED PATTERNS in nodeset(1) and also groups.conf(5) for more information).
Copy files¶
- # clush -w node[3-5,62] --copy /etc/motd
- Copy local file /etc/motd to remote nodes node[3-5,62].
- # clush -w node[3-5,62] --copy /etc/motd --dest /tmp/motd2
- Copy local file /etc/motd to remote nodes node[3-5,62] at path /tmp/motd2.
- # clush -w node[3-5,62] -c /usr/share/doc/clustershell
- Recursively copy local directory /usr/share/doc/clustershell to the same path on remote nodes node[3-5,62].
- # clush -w node[3-5,62] --rcopy /etc/motd --dest /tmp
- Copy /etc/motd from remote nodes node[3-5,62] to local /tmp directory, each file having their remote hostname appended, eg. /tmp/motd.node3.
FILES¶
- /etc/clustershell/clush.conf
- System-wide clush configuration file.
- ~/.clush.conf
- This is the per-user clush configuration file.
- ~/.clush_history
- File in which interactive clush command history is saved.
SEE ALSO¶
clubak(1), nodeset(1), readline(3), clush.conf(5), groups.conf(5).BUG REPORTS¶
- Use the following URL to submit a bug report or feedback:
- https://github.com/cea-hpc/clustershell/issues
AUTHOR¶
Stephane Thiell, CEA DAM <stephane.thiell@cea.fr>COPYRIGHT¶
CeCILL-C V1| 2012-04-01 | 1.6 |