Scale your PgBouncer
This is part of the PgBouncer Tutorial. Please refer to this page for more information and the overview of the content.
Adding and Removing units
Please check the explanation of scaling Charmed PostgreSQL operator here.
Add more pgbouncer instances
PgBouncer is a subordinated charm, it is enough to keep it as a single instance for each principal charm. To scale the principal charm use juju add-unit command (for a tutorial purpose let’s scale data-integrator):
juju add-unit data-integrator -n 2
You can now watch the scaling process in live using: juju status --watch 1s. It usually takes several minutes for new cluster members to be added. You’ll know that all three nodes are in sync when juju status reports Workload=active and Agent=idle:
Model Controller Cloud/Region Version SLA Timestamp
tutorial lxd localhost/localhost 3.1.6 unsupported 22:26:56+02:00
App Version Status Scale Charm Channel Rev Exposed Message
data-integrator active 3 data-integrator stable 13 no
pgbouncer 1.18.0 active 3 pgbouncer 1/stable 76 no
postgresql 14.9 active 1 postgresql 14/stable 336 no Primary
Unit Workload Agent Machine Public address Ports Message
data-integrator/1* active idle 2 10.3.217.158
pgbouncer/1* active idle 10.3.217.158
data-integrator/2 active idle 3 10.3.217.83
pgbouncer/3 active idle 10.3.217.83
data-integrator/3 active idle 4 10.3.217.35
pgbouncer/2 active idle 10.3.217.35
postgresql/0* active idle 0 10.3.217.79 5432/tcp Primary
Machine State Address Inst id Base AZ Message
0 started 10.3.217.79 juju-ca0eed-0 ubuntu@22.04 Running
2 started 10.3.217.158 juju-ca0eed-2 ubuntu@22.04 Running
3 started 10.3.217.83 juju-ca0eed-3 ubuntu@22.04 Running
4 started 10.3.217.35 juju-ca0eed-4 ubuntu@22.04 Running
The same way you can scale Charmed PostgreSQL:
juju add-unit postgresql -n 2
Make sure all units are active (using juju status):
Model Controller Cloud/Region Version SLA Timestamp
tutorial lxd localhost/localhost 3.1.6 unsupported 22:55:52+02:00
App Version Status Scale Charm Channel Rev Exposed Message
data-integrator active 3 data-integrator stable 13 no
pgbouncer 1.18.0 active 3 pgbouncer 1/stable 76 no
postgresql 14.9 active 3 postgresql 14/stable 336 no
Unit Workload Agent Machine Public address Ports Message
data-integrator/1* active idle 2 10.3.217.158
pgbouncer/1* active idle 10.3.217.158
data-integrator/2 active idle 3 10.3.217.83
pgbouncer/3 active idle 10.3.217.83
data-integrator/3 active idle 4 10.3.217.35
pgbouncer/2 active idle 10.3.217.35
postgresql/0* active idle 0 10.3.217.79 5432/tcp Primary
postgresql/1 active idle 5 10.3.217.147 5432/tcp
postgresql/2 active idle 6 10.3.217.114 5432/tcp
Machine State Address Inst id Base AZ Message
0 started 10.3.217.79 juju-ca0eed-0 ubuntu@22.04 Running
2 started 10.3.217.158 juju-ca0eed-2 ubuntu@22.04 Running
3 started 10.3.217.83 juju-ca0eed-3 ubuntu@22.04 Running
4 started 10.3.217.35 juju-ca0eed-4 ubuntu@22.04 Running
5 started 10.3.217.147 juju-ca0eed-5 ubuntu@22.04 Running
6 started 10.3.217.114 juju-ca0eed-6 ubuntu@22.04 Running
Remove extra members
Removing a unit from the application, scales the replicas down.
juju remove-unit data-integrator/2
juju remove-unit data-integrator/1
juju remove-unit postgresql/1
juju remove-unit postgresql/2
You’ll know that the replica was successfully removed when juju status --watch 1s reports:
Model Controller Cloud/Region Version SLA Timestamp
tutorial lxd localhost/localhost 3.1.6 unsupported 22:56:23+02:00
App Version Status Scale Charm Channel Rev Exposed Message
data-integrator active 1 data-integrator stable 13 no
pgbouncer 1.18.0 active 1 pgbouncer 1/stable 76 no
postgresql 14.9 active 1 postgresql 14/stable 336 no
Unit Workload Agent Machine Public address Ports Message
data-integrator/3* active idle 4 10.3.217.35
pgbouncer/2* active idle 10.3.217.35
postgresql/0* active idle 0 10.3.217.79 5432/tcp
Machine State Address Inst id Base AZ Message
0 started 10.3.217.79 juju-ca0eed-0 ubuntu@22.04 Running
4 started 10.3.217.35 juju-ca0eed-4 ubuntu@22.04 Running