Thread: PgBouncer - HA Mode

On 2020-02-17 11:42, Anjul Tyagi wrote:
> we are using PgBouncer for connection pooling, now all are application 
> is connecting database via PgBouncer. However I need suggestion, if some 
> how VM goes down or something goes wrong with PgBouncer, how can we 
> handle that situation. We observe that currently its a single point of 
> failure for all application if PgBouncer goes down.
> 
> Is there any kind of load balancer or replicate the PgBouncer ti manage 
> the high availability?

A typical approach is to run several pgbouncer instances on separate 
hosts and use a TCP/IP-level load balancer (e.g., hardware load balancer 
or HAProxy) to route traffic.

-- 
Peter Eisentraut              http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services

PgBouncer does not have internal failover-host configuration nor detection. It is possible via some external tools:

1. DNS reconfiguration - when ip behind DNS name is reconfigured, pgbouncer will reconnect to new server. This behaviour can be tuned via 2 config parameters - dns_max_ttl tunes lifetime for one hostname, and dns_zone_check_period tunes how often zone SOA will be queried for changes. If zone SOA record has changed, pgbouncer will re-query all hostnames under that zone.

2. Write new host to config and let PgBouncer reload it - send SIGHUP or use RELOAD; command on console. PgBouncer will detect changed host config and reconnect to new server.