tw_cluster_control utility enables you to perform the following operations:
- Review the status of all the machines across the cluster.
- Stop the services across the cluster.
- Restart the services across the cluster.
- Remove all failed machines from a cluster.
- Revert a cluster member into a standalone machine.
- Unlock the system when it is locked due to a cluster manager operation failure.
- Change the coordinator when the UI is inaccessible.
To use the utility, type the following command at the
$TIDEWAY/bin/ directory on a member of the cluster you need to control:
options are any of the options described in the following table and the common command line options described in Using command line utilities.
Command Line Option
Make this machine the coordinator.
Start the services on all machines across the cluster. This command does not restart the services, to do so, you must use --cluster-stop-services and then --cluster-start-services.
Message giving the reason for stopping the services across the cluster. Used in conjunction with
Stop the services on all machines across the cluster. This option prompts for the password of the system user.
Unlock the system when it is locked due to a cluster manager operation failure.
Do not ask for confirmation for any of the options.
Replaces a cluster member's VM UUID if it has changed, preventing the
in tw_svc_cluster_manager.log. See Troubleshooting clusters for more information.
Remove all failed machines from a cluster. You should use this if you are unable to forcibly remove one or more failed machines using the UI. This option prompts for the password of the system user.
Revert the local failed cluster member into a standalone machine. You should only use this after removing a failed machine from the cluster using the
Show the status of all the machines across the cluster.
Show any pending changes in the cluster.
In the following examples, you can stop and restart the services across the cluster, and launch troubleshooting operations if the cluster members are not accessible or are locked by BMC Atrium Discovery.
Review the status of the cluster members
You can request information about the current status of all machines in the cluster using the following command:
Cluster status example for a totally healthy cluster
This example contains the status information for a cluster where all members operate without failures and there are no connectivity issues.
Cluster status example with errors
This is an example of the cluster health check results for the case when only cluster coordinator is operating normally and other members of the cluster are down and inaccessible.
Restarting the services across the cluster
Stopping the services across the cluster
Unlock the system when it is locked due to a cluster manager operation failure
Some cluster management operations might acquire the system lock. If the operation is interrupted while the system is in a locked state, you might need to run the following command to unlock it:
Running the command unlocks only the machine that was affected by the interrupted operation. The interactive command line tool informs you if any additional intervention is required before you can run the
tw_cluster_control operations again for that machine.
For further examples using
tw_cluster_control to troubleshoot cluster problems, see troubleshooting clusters.