Book Image

PostgreSQL High Availability Cookbook - Second Edition

By : Shaun Thomas
Book Image

PostgreSQL High Availability Cookbook - Second Edition

By: Shaun Thomas

Overview of this book

Databases are nothing without the data they store. In the event of a failure - catastrophic or otherwise - immediate recovery is essential. By carefully combining multiple servers, it’s even possible to hide the fact a failure occurred at all. From hardware selection to software stacks and horizontal scalability, this book will help you build a versatile PostgreSQL cluster that will survive crashes, resist data corruption, and grow smoothly with customer demand. It all begins with hardware selection for the skeleton of an efficient PostgreSQL database cluster. Then it’s on to preventing downtime as well as troubleshooting some real life problems that administrators commonly face. Next, we add database monitoring to the stack, using collectd, Nagios, and Graphite. And no stack is complete without replication using multiple internal and external tools, including the newly released pglogical extension. Pacemaker or Raft consensus tools are the final piece to grant the cluster the ability to heal itself. We even round off by tackling the complex problem of data scalability. This book exploits many new features introduced in PostgreSQL 9.6 to make the database more efficient and adaptive, and most importantly, keep it running.
Table of Contents (18 chapters)
Title Page
About the Author
About the Reviewer
Customer Feedback

Installing and configuring Patroni

Patroni is the primary coordinating component of our stack. As we can see from figure 8-2, it is involved in every element of the stack to some degree. Though it ties all of the stack elements together, we're installing it next specifically because of how tightly it integrates with the key-value layer and PostgreSQL.

If a PostgreSQL server is already running, Patroni will adopt it. If not, Patroni will create a new instance based on how it's configured. We've already established that the key-value store distributes the same information across the entire cluster, so the first established server also becomes the primary node for the cluster. Any subsequent Patroni instance will start as-or transform itself into-a replica.

This means it's critically important to get this part right. Pay special attention to this recipe!

Getting ready

This recipe depends on multiple libraries and services. Please follow the Preparing systems for the stack and Installing and configuring...