ssh-para

ssh-para

Parallel SSH jobs manager CLI (alternative to parallel-ssh)

• POSIX/Linux/MacOS/Windows compatible (with openssh client installed)
• Launch parallel ssh jobs/scripts on remote hosts, with interactive display of the running commands outputs
• Keep all output in log files
• Interactive pause/resume/abort jobs, kill stuck ssh connection interactively.

installation

pip install ssh-para

By default, ssh-para uses Nerd Fonts glyphs, modern terminals can now render the glyphs without installing specific font (the symbols can be overridden with SSHP_SYM_* environment variables, see below)

quick start

Run command on multiple hosts:
$ ssh-para -H host1 host2 host3 -- echo connection ok
Review last run results:
$ ssh-para -l
Review hosts statuses for last run:
$ ssh-para -L *.status
View failed hosts list:
$ ssh-para -L failed.status
Show output of command on all hosts:
$ ssh-para -L *.out
Show output of command for failed hosts:
$ ssh-para -L *.failed
Show output of command for host1:
$ ssh-para -L host1.out

usage

ssh-para -h

usage: ssh-para [-h] [-V] [-j JOB] [-d DIRLOG] [-m MAXDOTS] [-p PARALLEL] [-t TIMEOUT] [-r] [-v] [-D DELAY]
                [-f HOSTSFILE | -H HOSTS [HOSTS ...] | -C {bash,zsh,powershell} | -l | -L LOGS [LOGS ...]] [-s SCRIPT]
                [-a ARGS [ARGS ...]]
                [ssh_args ...]

ssh-para v1.ssh-para.dev

positional arguments:
  ssh_args

options:
  -h, --help            show this help message and exit
  -V, --version         ssh-para version
  -j JOB, --job JOB     Job name added subdir to dirlog
  -d DIRLOG, --dirlog DIRLOG
                        directory for ouput log files (default: ~/.ssh-para)
  -m MAXDOTS, --maxdots MAXDOTS
                        hostname domain displaylevel (default:1 => short hostname, -1 => fqdn)
  -p PARALLEL, --parallel PARALLEL
                        parallelism (default 4)
  -t TIMEOUT, --timeout TIMEOUT
                        timeout of each job
  -r, --resolve         resolve fqdn in SSHP_DOMAINS
  -v, --verbose         verbose display (fqdn + line for last output)
  -D DELAY, --delay DELAY
                        initial delay in seconds between ssh commands (default=0.3s)
  -f HOSTSFILE, --hostsfile HOSTSFILE
                        hosts list file
  -H HOSTS [HOSTS ...], --hosts HOSTS [HOSTS ...]
                        hosts list
  -C {bash,zsh,powershell}, --completion {bash,zsh,powershell}
                        autocompletion shell code to source
  -l, --list            list ssh-para results/log directories
  -L LOGS [LOGS ...], --logs LOGS [LOGS ...]
                        get latest/current ssh-para run logs
                        -L[<runid>/]*.out          : all hosts outputs
                        -L[<runid>/]<host>.out     : command output of host
                        -L[<runid>/]*.<status>     : command output of hosts <status>
                        -L[<runid>/]*.status       : hosts lists with status
                        -L[<runid>/]<status>.status: <status> hosts list
                        -L[<runid>/]hosts.list     : list of hosts used to connect (resolved if -r)
                        default <runid> is latest ssh-para run (use -j <job> -d <dir> to access logs if used for run)
                        <status>: [success,failed,timeout,killed,aborted]
  -s SCRIPT, --script SCRIPT
                        script to execute
  -a ARGS [ARGS ...], --args ARGS [ARGS ...]
                        script arguments

During run, use :

• k: to kill ssh command held by a thread (but remote command can still be running on remote host)
• p: pause all remaining jobs to be scheduled
• r: resume scheduling of jobs
• a: abort all remaining jobs
• ctrl-c: stop all/exit (but remote commands launched by ssh can still be running on remote servers)

Environment variables:

• SSHP_OPTS: ssh default options (Eg: "-F /home/user/.ssh/myconfig")
• SSHP_DOMAINS: dns domains to search when short hostname given (with -r/--resolve option)
• SSHP_SYM_BEG: Symbol character for begin decorative (default: "\ue0b4")
• SSHP_SYM_END: Symbol character for end decorative (default: "\ue0b6")
• SSHP_SYM_PROG: Symbol character for progress bar fill (default: "\u25a0")
• SSHP_SYM_RES: Symbol character before ssh output line (default: "\u25b6")

Activate autocompletion:

• . <(ssh-para -C bash)
• ssh-para -C powershell | Out-String | Invoke-Expression

Example

Patch redhat family hosts:

ssh-para -p 20 -f hostlist.txt -- 'sudo yum update -y;sudo shutdown -r +1'

Use specific ssh options / config (everything after -- will be passed to ssh command as is):

ssh-para -p 20 -H host1 host2 -- -F ~/.ssh/myconfig echo connect ok

Launch local script with argument on remote hosts:

ssh-para -p 20 -f hosts.txt -s ./myscript -a status

Extend limited resolv.conf search domains (try to resolve host in each domain, first resolved in the domain list is used as fqdn):

SSHP_DOMAINS="domain1.com domain2.com" ssh-para -r -H host1 host2 -- echo connect ok

Tips

• ssh-para uses ssh BatchMode, no interactive password/passphrase will be asked, so you need to have a ssh authorized key to connect to servers (ssh-agent...)
• you need to configure your ssh for StrictHostKeyChecking/UserKnownHostsFile if you need to connect to unknown servers
• to connect as different user use ssh -l option or define everything in your ssh config file
  • you can use user@host as hostname but not if you need to resolve host (-r/--resolve)
• if you are using ssh ProxyJump server to reach hosts, you may need to tweak the sshd MaxStartups setting on the ssh Proxy server with high parallelism
  • when ssh-para starts, a delay of 0.3 seconds is applied between threads starting ssh jobs to avoid flooding, (can be tweaked with -D )
• if you are using remote connexion to launch the ssh-para, use screen to launch ssh-para, as if you lose your connection, ssh-para will be still running and you can re-attach to screen to continue follow-up.
• Be very carefull when launching massive commands on servers... Always first test on non production.