cl

cl is a simple tool that allows you to run multiple commands concurrently across a cluster of servers via SSH. It works by taking the name of the cluster to run the command across, followed by the command to run like so.

$ cl uat systemctl status postgresql

cl expects a ClFile to be in the current directory from where the command is invoked. This is a plain-text file that describes the cluster, and how they can be accessed via SSH.

uat:
  db@db-host-1 ~/.ssh/id_rsa
  db@db-host-2 ~/.ssh/id_rsa
  db@db-host-3 ~/.ssh/id_rsa

The ClFile

The ClFile expects the cluster of servers to be organised in the below format, where the heading is the name that will be used via the command, and each subsequent entry is the server to connect to.

[name]:
  [user]@[host]:[port] [identity]

[name]:

A human readable string that specifies the alias for the cluster machines.

[user]

The user to connect to the machine as, if not specified then $USER will be used instead.

[host]

The host to connect to, this is always required.

[port]

The port to connect to on the machine, if not specified then 22 will be used instead.

[identity]

The identity file to use during SSH authentication, if not specified then ~/.ssh/id_rsa will be used by default.

There is no limit to the number of clusters that can be specifed in the ClFile.

uat:
  db@db-host-1 ~/.ssh/id_rsa
  db@db-host-2 ~/.ssh/id_rsa
  db@db-host-3 ~/.ssh/id_rsa

prod:
  db@prod-db-host1:1234 ~/.ssh/id_prod_db
  prod-db-host2:44
  prod-db-host3 ~/.ssh/id_rsa