In a single data service dataservice configuration, the Primary can be switched between nodes within the dataservice manually using cctrl . The switch command performs the switch operation, annotating the progress.

[LOGICAL:EXPERT] /alpha > switch
SET POLICY: AUTOMATIC => MAINTENANCE
EVALUATING SLAVE: db3(stored=14, applied=14, latency=0.682, datasource-group-id=0)
EVALUATING SLAVE: db2(stored=14, applied=14, latency=0.686, datasource-group-id=0)
SELECTED SLAVE: db3@alpha
Savepoint switch_2(cluster=alpha, source=db2, created=2025/01/27 13:54:48 UTC) created
PURGE REMAINING ACTIVE SESSIONS ON CURRENT MASTER 'db1@alpha'
PURGED A TOTAL OF 0 ACTIVE SESSIONS ON MASTER 'db1@alpha'
FLUSH TRANSACTIONS ON CURRENT MASTER 'db1@alpha'
PUT THE NEW MASTER 'db3@alpha' ONLINE
PUT THE PRIOR MASTER 'db1@alpha' ONLINE AS A SLAVE
SWITCH TO 'db3@alpha' WAS SUCCESSFUL

By default, switch chooses the most up to date Replica within the dataservice ( db3 in the above example), but an explicit Replica can also be selected:

[LOGICAL:EXPERT] /alpha > switch to db2
SET POLICY: AUTOMATIC => MAINTENANCE
EVALUATING SLAVE: db2(stored=22, applied=22, latency=0.974, datasource-group-id=0)
SELECTED SLAVE: db2@alpha
Savepoint switch_4(cluster=alpha, source=db2, created=2025/01/27 13:56:07 UTC) created
PURGE REMAINING ACTIVE SESSIONS ON CURRENT MASTER 'db1@alpha'
PURGED A TOTAL OF 0 ACTIVE SESSIONS ON MASTER 'db1@alpha'
FLUSH TRANSACTIONS ON CURRENT MASTER 'db1@alpha'
PUT THE NEW MASTER 'db2@alpha' ONLINE
PUT THE PRIOR MASTER 'db1@alpha' ONLINE AS A SLAVE
SWITCH TO 'db2@alpha' WAS SUCCESSFUL

With the previous example, the switch occurred specifically to the node db2 .