Chapter 11: Minimizing Downtime with Rolling Deployments

Ansible is well suited to the task of upgrading or deploying applications in a live service environment. Of course, application deployments and upgrades can be approached with a variety of different strategies. The best approach depends on the application itself, the capabilities of the infrastructure the application runs on, and any promised service-level agreements (SLAs) with the users of the application. Whatever the approach, it is vital that the application deployment or upgrade is controlled, predictable, and repeatable in order to ensure that users experience a stable service while automated deployments occur in the background. The last thing anyone wants is an outage caused by unexpected behavior from their automation tool; an automation tool should be trustworthy and not an additional risk factor.

Although there is a myriad of choices, some deployment strategies are more common than others, and in this chapter, we...