A complete guide to implementing H/A of the OpenStack services is probably worth a book to itself. In this chapter we started out by covering the main strategies for making OpenStack services highly available and identifying which strategies apply well to each service. Then we covered how OpenStack deployments are typically segmented across physical regions. Finally, we updated our documentation and implemented a few of the technologies we discussed in the lab.
While walking through the main considerations for highly available deployments in this chapter, we've tried to emphasize a few key points:
Scalability is at least as important as H/A in cluster design.
Ensure that your design is flexible in case of unexpected growth.
OpenStack doesn't scale forever. Plan for multiple regions.
Also, it's important to make sure that the strategy and architecture that you adopt for H/A are supportable by your organization. Consider reusing existing architectures for H/A in the message bus and database...