...

There can be situations when a Controller Cluster should be reverted for use with to act as a Standalone Controller:

• In case of an architecture decision to continue with a Standalone Controller.
• In case of severe loss of cluster-related data, for example if journals of both a Controller instance and of the Cluster Watch Agent have not been consistently written to disk or are not available after a server crash or file system crash.

Converting a Controller Cluster to a Standalone Controller offers to re-instate the Cluster at a any later point in time.

Revoking the Controller Cluster

...

• In most situations this will be the previously active Controller instance.
• Users should remove the journal of the previously previous standby Controller instance, precisely they should remove the contents of the Controller instance's state folder. This measure prevents a situation when later on the previous standby Controller instance is will be started by chance and invites will invite the Standalone Controller instance to re-establish the cluster.

...

# reverting Controller Journaljournal for Unix with no running Controller instances
./controller_instance.sh revoke

# reverting Controller Journaljournal for Unix with a running Controller instance that is stopped and reverted
./controller_instance.sh stop --revoke

@rem reverting Controller Journaljournal for Unix with no running Controller instances
./controller_instance.cmd revoke

@rem reverting Controller Journaljournal for Unix with a running Controller instance that is stopped and reverted
.\controller_instance.cmd stop --revoke

...

• Running the above script will remove any cluster related items from the Controller instance's journal.
• This allows the Controller instance to be started as a Standalone instance.
  • Standalone Controllers
    • do not connect to a Cluster Watch Agent,
    • do not connect nor can be connected to/from a second Controller instance acting for in a standby role.

Configuring the Standalone Controller

...

The initial radio buttons Standalone and Cluster determine the Controller type. Users can modify the Controller type to Standalone and enter the URL of the Controller instance that is should be used as a Standalone Controller like this:

...