Scale your PgBouncer K8s

This is part of the PgBouncer K8s 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 K8s operator here.

Add more PgBouncer instances

You can add two more units to your deployed PgBouncer application by scaling it using:

juju scale-application pgbouncer-k8s 3

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
test16  microk8s    microk8s/localhost  3.1.6    unsupported  22:16:20+02:00

App              Version  Status  Scale  Charm            Channel    Rev  Address         Exposed  Message
data-integrator           active      1  data-integrator  stable      13  10.152.183.136  no       
pgbouncer-k8s    1.18.0   active      3  pgbouncer-k8s    1/stable    76  10.152.183.84   no       
postgresql-k8s   14.9     active      1  postgresql-k8s   14/stable  158  10.152.183.92   no       Primary

Unit                Workload  Agent  Address     Ports  Message
data-integrator/0*  active    idle   10.1.12.16         
pgbouncer-k8s/0*    active    idle   10.1.12.15         
pgbouncer-k8s/1     active    idle   10.1.12.61         
pgbouncer-k8s/2     active    idle   10.1.12.50         
postgresql-k8s/0*   active    idle   10.1.12.6          Primary

You can scale Charmed PostgreSQL in the same way:

juju scale-application postgresql-k8s 3

Make sure all units are active using juju status:

Model   Controller  Cloud/Region        Version  SLA          Timestamp
test16  microk8s    microk8s/localhost  3.1.6    unsupported  22:18:00+02:00

App              Version  Status  Scale  Charm            Channel    Rev  Address         Exposed  Message
data-integrator           active      1  data-integrator  stable      13  10.152.183.136  no       
pgbouncer-k8s    1.18.0   active      3  pgbouncer-k8s    1/stable    76  10.152.183.84   no       
postgresql-k8s   14.9     active      3  postgresql-k8s   14/stable  158  10.152.183.92   no       

Unit                Workload  Agent  Address     Ports  Message
data-integrator/0*  active    idle   10.1.12.16         
pgbouncer-k8s/0*    active    idle   10.1.12.15         
pgbouncer-k8s/1     active    idle   10.1.12.61         
pgbouncer-k8s/2     active    idle   10.1.12.50         
postgresql-k8s/0*   active    idle   10.1.12.6          Primary
postgresql-k8s/1    active    idle   10.1.12.35         
postgresql-k8s/2    active    idle   10.1.12.39

Remove extra members

Removing a unit from the application scales the replicas down.

juju scale-application pgbouncer-k8s 2

juju scale-application postgresql-k8s 2

You’ll know that the replica was successfully removed when juju status --watch 1s reports:

Model   Controller  Cloud/Region        Version  SLA          Timestamp
test16  microk8s    microk8s/localhost  3.1.6    unsupported  22:19:10+02:00

App              Version  Status  Scale  Charm            Channel    Rev  Address         Exposed  Message
data-integrator           active      1  data-integrator  stable      13  10.152.183.136  no       
pgbouncer-k8s    1.18.0   active      2  pgbouncer-k8s    1/stable    76  10.152.183.84   no       
postgresql-k8s   14.9     active      2  postgresql-k8s   14/stable  158  10.152.183.92   no       

Unit                Workload  Agent  Address     Ports  Message
data-integrator/0*  active    idle   10.1.12.16         
pgbouncer-k8s/0*    active    idle   10.1.12.15         
pgbouncer-k8s/1     active    idle   10.1.12.61         
postgresql-k8s/0*   active    idle   10.1.12.6          Primary
postgresql-k8s/1    active    idle   10.1.12.35