Deploy Async replication
Deploy
Deploy two MySQL Clusters, named Rome and Lisbon:
juju add-model rome # 1st cluster location: Rome
juju add-model lisbon # 2nd cluster location: Lisbon
juju switch rome
juju deploy mysql db1 --channel=8.0/edge --config profile=testing --config cluster-name=rome --base ubuntu@22.04
juju switch lisbon
juju deploy mysql db2 --channel=8.0/edge --config profile=testing --config cluster-name=lisbon --base ubuntu@22.04
Note: remove profile configuration for production deployments. Check Profiles for documentation.
Offer
Offer asynchronous replication on the Primary cluster (Rome):
juju switch rome
juju offer db1:replication-offer replication-offer
(Optional) Offer asynchronous replication on StandBy cluster (Lisbon), for the future:
juju switch lisbon
juju offer db2:replication-offer replication-offer
Consume
Consume asynchronous replication on planned StandBy cluster (Lisbon):
juju switch lisbon
juju consume rome.replication-offer
juju integrate replication-offer db2:replication
Once relations are established, cluster Rome will get into Blocked state, waiting for the replication to be created.
To do so, run the action create-replication on rome’s leader unit.
juju switch rome
juju run db1/leader create-replication
(Optional) Consume asynchronous replication on the current Primary (Rome), for the future:
juju switch rome
juju consume lisbon.replication-offer
Status
Run the get-cluster-status action with the cluster-set=True flag:
juju run -m rome db1/0 get-cluster-status cluster-set=True
Results:
status:
clusters:
lisbon:
clusterrole: replica
clustersetreplicationstatus: ok
globalstatus: ok
rome:
clusterrole: primary
globalstatus: ok
primary: 10.82.12.22:3306
domainname: cluster-set-bcba09a4d4feb2327fd6f8b0f4ac7a2c
globalprimaryinstance: 10.82.12.22:3306
primarycluster: rome
status: healthy
statustext: all clusters available.
success: "True"
Scaling
The two clusters works independently, this means that it’s possible to independently scaling in/out each cluster without much hassle, e.g.:
juju add-unit db1 -n 2 -m rome
juju add-unit db2 -n 2 -m lisbon
Note: The scaling is possible before and after the asynchronous replication established/created.