DevOps: Puppet, Docker, and Kubernetes

Using the in operator

The in operator tests whether one string contains another string. Here's an example:

if 'spring' in 'springfield'

The preceding expression is true if the spring string is a substring of springfield, which it is. The in operator can also test for membership of arrays as follows:

if $crewmember in ['Frank', 'Dave', 'HAL' ]

When in is used with a hash, it tests whether the string is a key of the hash:

$ifaces = { 'lo'   => '127.0.0.1', 
            'eth0' => '192.168.0.1' }
if 'eth0' in $ifaces {
  notify { "eth0 has address ${ifaces['eth0']}": }
}

How to do it…

The following steps will show you how to use the in operator:

1. Add the following code to your manifest:

   if $::operatingsystem in [ 'Ubuntu', 'Debian' ] { notify { 'Debian-type operating system ...