Arbiter is a connection proxy for PostgreSQL, intended to simplify operations of streaming replication setups.
When you start Arbiter, it listens on the primary and follower addresses defined in arbiter.cfg.
Connections to the primary will always be routed to the backend that has the primary role.
Connections to the follower will be routed to the closest backend, measured by latency, regardless if that backend is a primary or a follower.
You should configure your application to connect to the primary if it performs destructive operations. Connections to the follower should only be used for queries.
[main]
;; Connections to the primary address will get routed to
;; the primary backend. Suitable for INSERT/UPDATE/DELETEs.
primary = 127.0.0.1:5433
;; Connections to the follower address will get routed to
;; any backend. Suitable for SELECTs.
follower = 127.0.0.1:5434
;; Backends is a comma seperated list of backend servers.
backends = pg1:5432, pg2:5432
[health]
;; The username and password pair describe a PostgreSQL user that has SELECT permissions.
;; Used to query the status of the backends.
username = arbiter
password = arbiter
database = repmgr