DSH is Distributed Shell. It allows you to run shell commands on multiple servers at once and gather see their output in local terminal.
Install
Install On Debian/Ubuntu
apt-get install dsh
Mac
brew install dsh
Config
You can use default config but we always add following to dsh config file:
Global config => /etc/dsh.conf
Local config => ~/.dsh/dsh.conf
remoteshell = ssh
showmachinenames = 1
Hostname List
Edit/create
Global list => /etc/dsh/machines.list
Local list => ~/.dsh/dsh/machines.list
Add hostnames, one on each line.
Please note that, you need to add SSH key’s separately (beforehand).
example.com
example.net
Usage
We need to pass actual command to dsh command with optional prameters:
Lets check uptime
dsh -a uptime
You will see output as below
example.com: 18:07:18 up 294 days, 6:38, 3 users, load average: 0.17, 0.26, 0.24
example.net: 18:09:47 up 9 days, 19:54, 1 user, load average: 0.26, 0.2
-a denotes run for all hosts.
We can also pass -c which will create concurrent connections to all servers.
Grouping Hosts/Servers
You can make group and run dsh command on that group servers only.
You can add a file under group directory like below
Global settings => /etc/dsh/group/hello
Local settings => ~/.dsh/dsh/group/hello
Add list of hostnames. You can add multiple hostnames to groups
hello.com
hello.net
hello.org
Lets check uptime on hello group servers:
dsh -g hello uptime
Will display something like
hello.com: 18:11:45 up 9 days, 19:56, 0 users, load average: 0.05, 0.18, 0.22
hello.net: 18:11:45 up 19 days, 19:56, 0 users, load average: 0.15, 0.18, 0.22
hello.org: 18:11:45 up 119 days, 19:56, 0 users, load average: 0.15, 1.8, 0.22
Web-Based Alternative
If you are looking for web-based service which does things like this, you may try https://commando.io/. It has some really nice features and a free plan for 2 users.