Handling a PostgreSQL Database Failover

Edge for Private Cloud v. 4.16.09

Perform the following during a PostgreSQL database failover:

1. Stop apigee-postgresql on the current master if it is still running:
   > /<inst_root>/apigee/apigee-service/bin/apigee-service apigee-postgresql stop
2. Go to standby node and invoke the following command to make it the master:
   > /<inst_root>/apigee/apigee-service/bin/apigee-service apigee-postgresql promote-standby-to-master IPorDNSofOldMaster

If old master is restored at some time in the future, make it a standby node:

1. On the current master, edit the config file to set:
   PG_MASTER=IPorDNSofNewMaster
   PG_STANDBY=IPorDNSofOldMaster
2. Enable replication on the new master:
   > /<inst_root>/apigee/apigee-service/bin/apigee-service apigee-postgresql setup-replication-on-master -f configFIle
3. On the old master, edit the config file to set:
   PG_MASTER=IPorDNSofNewMaster
   PG_STANDBY=IPorDNSofOldMaster
4. Stop apigee-postgresql on the old master:
   > /opt/apigee/apigee-service/bin/apigee-service apigee-postgresql stop
5. On the old master, clean out any old Postgres data:
   > rm -rf /<inst_root>/apigee/data/apigee-postgresql/
   
   Note: If necessary, you can backup this data before deleting it.
6. Configure the old master as a standby:
   > /<inst_root>/apigee/apigee-service/bin/apigee-service apigee-postgresql setup-replication-on-standby -f configFile
7. On completion of replication, verify the replication status by issuing the following scripts on both servers. The system should display identical results on both servers to ensure a successful replication:
   1. On the master node, run:
      > /<inst_root>/apigee/apigee-service/bin/apigee-service apigee-postgresql postgres-check-master
      
      Validate that it says it is the master.
   2. On the standby node:
      > /<inst_root>/apigee/apigee-service/bin/apigee-service apigee-postgresql postgres-check-standby
      
      Validate that it says it is the standby.