PostgreSQL 12 High Availability Cookbook - Third Edition

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The analogous process of adding a node to the cluster stack is to remove one. That procedure is considerably easier, in general. For example, we could execute these commands as a root-level user in order to remove pgha2 from our Patroni cluster:

sudo systemctl stop patroni
export MEMBER=$(etcdctl member list | grep pgha2 | cut -d ':' -f 1)
etcdctl member remove $MEMBER

Since the etcd layer is persistent across all nodes, pgha2 is permanently removed from all of them unless we add it again by following this recipe. Once Patroni is stopped and etcd no longer considers the pgha2 part of the key-value layer, we can safely recycle the server without worry.

We also need to remove references to pgha2 from the HAProxy configuration ...