Crunchy Data products often include High Availability. Patroni and etcd are two of our go-to tools for managing those environments. Today I wanted to explore how these work together. Patroni relies on proper operation of the etcd cluster to decide what to do with PostgreSQL. When communication between these two pieces breaks down, it creates instability in the environment resulting in failover, cluster restart, and even the the loss of a primary database. To fully understand the importance of this relationship, we need to understand a few core concepts of how these pieces work. First, we'll start with a brief overview of the components involved in HA systems and their role in the environment.
