Practical Ansible 2

Control play execution for rolling updates

By default, Ansible parallelizes tasks on multiple hosts at the same time to speed up automation tasks in large inventories. The setting for this is defined by the forks parameter in the Ansible configuration file, which defaults to 5 (so, by default, Ansible attempts to run its automation job on five hosts at the same time).

In a load-balanced environment, this is not ideal, especially if you want to avoid downtime. Suppose we have five frontend servers in an inventory (or perhaps even fewer). If we allow Ansible to update all of these at the same time, the end users may experience a loss of service. So, it is important to consider updating all of the servers at different times. Let's reuse our ...