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

Replacing etcd with ZooKeeper

It's common for server stacks to already partially exist; often using components we don't have the privilege of choosing. Servers and related software can be around for years before we adapt them to our needs. Thus it's possible an infrastructure department already uses a distributed key-value storage system like etcd for its own purposes.

ZooKeeper is one of these alternative key-value storage layers. Patroni is fully capable of utilizing this instead of etcd, provided we make some changes to how it is configured.

Let's leverage an existing ZooKeeper installation to our advantage!


Please note that installing ZooKeeper itself is beyond the scope of this recipe. The intention here is to make changes to Patroni that make it compatible with an existing ZooKeeper installation. This can happen when an infrastructure already incorporates ZooKeeper, allowing us to leverage it as well.

Getting ready

This recipe depends on the presence of the entire stack, as well as...