In order for Patroni to reliably determine or define the identity of the primary PostgreSQL instance, we need a distributed key-value layer. In this recipe, we'll be installing etcd to fulfil that role.
The etcd maintainers appear to have designed it to operate primarily in nameless virtual containers. This means we just need to download it and place some binaries in appropriate locations. It's not an ideal installation with reliable configuration files and other expected components, but that's easily rectified if we decide to rely on etcd long-term.
Let's get started.
The etcd service doesn't seem to be a commonly provided package in many Linux distributions. The project itself moves rapidly as well; the version changed four times while this book was being written. As such, we recommend obtaining the latest stable release provided at this URL:
While we use 3.0.14 as the version number in our instructions, don...