Chapter 1. Overview

This guide describes how to implement Instance High Availability (Instance HA). Instance HA allows Red Hat OpenStack Platform to automatically re-spawn instances on a different Compute node when their host Compute node breaks.

Instance HA automates the evacuation of an instance whenever its host Compute node fails. The evacuation process triggered by Instance HA is similar to what users can do manually, as described in Evacuate Instances. Instance HA works on shared storage and local storage environments, which means that evacuated instances will maintain the same network configuration (static ip, floating ip, and so on) and characteristics inside the new host, even if they are spawned from scratch.

Instance HA is managed by three resource agents:

This guide focuses on enabling Instance HA on an overcloud through Ansible.