/ 
App-RemoteCommand-0.97
River stage zero No dependents
/ App::RemoteCommand::Tutorial

NAME

App::RemoteCommand::Tutorial - tutorial!

TUTORIAL

App::RemoteCommand or its frontend rcommand is a simple remote command launcher via ssh. You can use it like ssh command.

Let's say you have 6 hosts:

www001.example.com, www002.example.com, www003.examle.com,
www001.example.jp,  www002.example.jp,  www003.examle.jp

and you can ssh these hosts without password or passphrase. If your ssh private key needs a passphrase, please setup ssh-agent first.

1. simple

The usual form is (much like ssh command):

> rcommand HOSTS COMMANDS

For example, to execute uname command in www001.example.com:

> rcommand www001.example.com uname
[www001.example.com] Linux
SUCCESS www001.example.com

Add www002.example.com too:

> rcommand 'www001.example.com,www002.example.com' uname
[www001.example.com] Linux
[www002.example.com] Linux
SUCCESS www001.example.com
SUCCESS www002.example.com

Oh, you can use range notation [*-*] instead of using just separator ,:

> rcommand 'www[001-003].example.com' uname
[www001.example.com] Linux
[www002.example.com] Linux
[www003.example.com] Linux
SUCCESS www001.example.com
SUCCESS www002.example.com
SUCCESS www003.example.com

and choice notation {*,*}:

> rcommand 'www001.example.{com,jp}' uname
[www001.example.com] Linux
[www001.example.jp] Linux
SUCCESS www001.example.com
SUCCESS www001.example.jp

of course both at the same time:

> rcommand 'www00[1-2].example.{com,jp}' uname
[www001.example.com] Linux
[www002.example.com] Linux
[www001.example.jp] Linux
[www002.example.jp] Linux
SUCCESS www001.example.com
SUCCESS www002.example.com
SUCCESS www001.example.jp
SUCCESS www002.example.jp
2. execute local script

Sometimes it is hard to write command in one liner. Why don't you write a script in local and execute it with rcommand :

> cat local-script.sh
#!/bin/bash
percent=`df -h | grep /dev/sda1 | perl -anle '$F[-2] =~ s/%//; print $F[-2]'`
if [ $percent -lt 80 ]; then
  echo "OK $percent%"
else
  echo "NG $percent%"; exit 1
fi

> rcommand --script local-script.sh 'www00[1-2].example.jp'
[www002.example.jp] OK 65%
[www001.example.jp] NG 85%
FAIL www001.example.jp
SUCCESS www002.example.jp

Note that the SUCCESS/FAIL summary is displayed in the end.

3. sudo password

If you want to run command which includes sudo command, please execute rcommand with --ask-sudo-password option:

> rcommand --ask-sudo-password 'www00[1-2].example.jp' sudo service cron restart
sudo password (asking with rcommand):
[www002.example.jp] sudo password (asking with rcommand):
[www002.example.jp]
[www001.example.jp] sudo password (asking with rcommand):
[www001.example.jp]
[www002.example.jp] cron stop/waiting
[www002.example.jp] cron start/running, process 7416
...
4. misc

You can specify target hosts by host file with --host-file option:

> cat host.txt
# comment
www001.example.jp
www002.example.com

> rcommand --host-file host.txt 'w | head -n1'
[www002.example.com]  15:35:11 up  2:00,  1 user,  load average: 0.00, 0.01, 0.05
[www001.example.jp]  15:35:12 up  2:00,  2 users,  load average: 0.03, 0.03, 0.05
...

You can append current time to each output line with --append-time option:

> rcommand --append-time www001.example.jp 'echo 1; sleep 1; echo 2'
[2015-01-05 00:36:58][www001.example.jp] 1
[2015-01-05 00:36:59][www001.example.jp] 2
...

You can remove hostname in each output line with --no-append-hostname option:

> rcommand --no-append-hostname www001.example.jp 'uname -a'
Linux vagrant-ubuntu-trusty-64 3.13.0-30-generic #55-Ubuntu SMP Fri Jul 4 21:40:53 UTC 2014 x86_64 x86_64 x86_64 GNU/Linux
SUCCESS www001.example.jp

By default, rcommand execute command in 5 parallel. You can change it with --concurrency option:

> rcommand --concurrency 1 -a 'www00[1-3].example.{jp,com}' sudo service httpd stop
...
5. help

Please type:

> rcommand --help