Ubuntu : Install packages on a cluster of machines

Sometimes, you have a cluster of machines where some packages need to be installed. It would be nice to be able to automate this so that you could do everything from a single terminal. We have seen how a command can be run on multiple machines from a single terminal before. This only works if you have password-less ssh set up between the machine that you are running the command from and the cluster on which you want the command to actually run. The only aspect that makes this a little harder for installing software is that you need to be root to install packages and ssh keys are not generally set-up for root.

However, there is an option -S that you can provide sudo that will make sudo read the password from stdin. We can use this combined with the bash loop to come up with a one liner that would install a package across a cluster of machines.

for m in m1 m2 m3 m4 ; do echo $m; ssh $m "echo password | sudo -S apt-get -y install curl" ; done

The -S option makes sure that the command will not prompt you for a password or complain about a missing tty. The -y option for apt-get prevents it from prompting you prior to the install.