Configure high availability

The purpose of a high availability configuration is to reduce downtime when a database cluster instance becomes unavailable. This might happen when an instance runs out of memory. With high availability, your data continues to be available to client applications.

Within a site, the configuration is made up of a primary instance and a standby replica. All writes made to the primary instance are replicated to the standby replica before a transaction is reported as committed. In the event of an instance failure, you can request that the standby replica become the new primary instance. Application traffic is then rerouted to the new primary instance. This process is called a failover.

You can manually trigger a failover at any time. The failover involves the following process, in order:

1. GDC takes the primary instance offline.

2. GDC turns the standby replica into the new active database cluster.

3. GDC deletes the previous active database cluster.

4. GDC creates a new standby replica.

Update an existing cluster

You can update your high availability settings for an existing database cluster:

Console

1. In the navigation menu, select Database Service.

2. From the database cluster list, click the database cluster to update.

3. Select edit Edit in the High availability section.

   

4. Select Enable same zone standby to either toggle on or off the availability of a standby instance in the same zone as your primary database cluster.

5. Click Save.

6. Verify your database cluster reflects your high availability update by viewing its status in the High availability column of the database cluster list.

gdcloud

1. Update your database cluster's high availability configuration:

   gdcloud database clusters update CLUSTER_NAME \
       --availability-type HA_TYPE
   

   Replace the following:

   • CLUSTER_NAME: the name of the database cluster.
   • HA_TYPE: the high availability level for the database cluster. You can set zonal or zonal_ha. The zonal value is set by default.

2. Verify your database cluster reflects your high availability update:

   gdcloud database clusters list
   

API

1. Update your database cluster's high availability configuration:

     kubectl patch dbcluster.postgresql.dbadmin.gdc.goog DBCLUSTER_NAME \
       -n USER_PROJECT \
       -p '{"spec": {"availability": {"enableHighAvailability": HA_ENABLED}}}' \
       --type=merge
   

   Replace the following variables:

   • DBCLUSTER_NAME: the name of the database cluster.
   • USER_PROJECT: the name of the user project where the database cluster was created.
   • HA_ENABLED: the high availability level for the database cluster. You can set true or false. The false value is set by default.

2. Verify your database cluster reflects your high availability update:

   kubectl get dbcluster.DBENGINE_NAME.dbadmin.gdc.goog DBCLUSTER_NAME \
     -n USER_PROJECT \
     -o yaml
   

Migrate to the latest high availability implementation

To verify that your high availability database cluster is using the latest implementation, check if the annotation dbcluster.dbadmin.goog/raasEnabled exists on your high availability database cluster CR. This annotation will only appear on clusters using the new implementation. If you don't have this annotation, you can enable it and migrate your cluster with the following steps:

1. Check with your Infrastructure Operator that your GDC environment is upgraded to version 1.15.1 or later.
2. Disable high availability on your database cluster. Wait for the HAReady condition to disappear, and then re-enable high availability.
3. After you see HAReady in progress or HAReady setup complete, check your database cluster CR for the annotation dbcluster.dbadmin.goog/raasEnabled. If it appears, then your database cluster has been successfully migrated.

Trigger a failover

If you have configured high availability for your database cluster, you can trigger a failover. To trigger a failover, complete the following steps:

Console

1. In the navigation menu, select Database Service.

2. From the database cluster list, click the database cluster to trigger a failover for. Your database cluster must have high availability enabled to be eligible for a failover.

3. Click Failover.

4. Type the cluster's ID for the confirmation phrase and click Failover to trigger the failover process.

gdcloud

• Trigger the failover for the database cluster:

  gdcloud database clusters failover CLUSTER_NAME
  

  Replace CLUSTER_NAME with the name of the database cluster.

API

  apiVersion: fleet.dbadmin.gdc.goog/v1
  kind: Failover
  metadata:
    name: FAILOVER_NAME
  spec:
    dbclusterRef: DBCLUSTER_NAME

Replace the following variables:

• DBCLUSTER_NAME, the name of the database cluster.
• FAILOVER_NAME, the unique name of the failover, for example failover-sample.