Greg Karékinian 0b63bc954f Add initial docs for PostgreSQL replication

Document how to switch the PostgreSQL primary server to a standby, for
the case where the primary goes down.

Refs #217

2020-12-18 17:14:40 +01:00

Switch PostgreSQL primary

Change the role in ./nodes/#{new_primary}.json's run list:

-    "role[postgresql_replica]",
+    "role[postgresql_primary]",

Delete the role[postgresql_replica] role from the old primary's run list.

Run Chef on the new primary, then create the failover file to turn the server into the new primary:

$ sudo touch /mnt/data/postgresql/failover.trigger

Run Chef on servers that use PostgreSQL to change the IP of the primary server.