Sometimes we would only want to execute some initialization configurations on Puppet agent only on the first of manifest application. One approach is to create a text file and only skip the execution when that file exists.

• Puppet – Run exec once only

Here is another example written on the Puppet CookBook.

# run exec only if command in onlyif returns 0.
exec { "run_account_purger":
  command => "/usr/local/sbin/account_purger",
  onlyif => "grep -c old_account /etc/passwd",
}

# or run multiple commands - all must succeed for exec to run
exec { "run_account_purger":
  command => "/usr/local/sbin/account_purger",
  onlyif => [ 
              "grep -c old_account /etc/passwd", 
              "test -d /home/old_account/"
            ],
}

Done =)

Reference: Puppet CookBook – Selective exec running