Salt versus Ansible versus Puppet versus PalletOps execution models

While the configuration systems we explore in this chapter share a fair number of similarities, they differ a lot in the way code is executed on the client nodes:

• With Puppet, a Puppet agent registers with the Puppet master and opens a communication channel to retrieve commands. This process is repeated periodically, normally every thirty minutes.

  Note

  Thirty minutes isn't fast. You can, of course, configure a lower value for the time interval required for the next run. At any rate, Puppet essentially uses a pull model. Clients must check in to know whether changes are available.

• Ansible pushes changes over SSH when desired. This is a push model.
• Salt uses a push model, but with a different implementation. It employs a ZeroMQ messaging server that the clients connect to and listen for notifications about changes. This works a bit like Puppet, but faster.

Which method is best is an area of contention between developer communities...