Default language.

Reverting a cluster member into a standalone machine

Warning

This is a recovery operation. It might break the cluster and you might lose data. All data is removed from the machine that is reverted to a standalone machine. If the cluster does not have fault tolerance enabled, or if multiple machines have failed, you will lose all data in the cluster.

You might need to convert a member of the cluster into a standalone machine in the following circumstances:

  • When the machine that was unresponsive and was forcibly removed from the cluster becomes available. If you cannot force remove the machine using the UI, you can do so from the command line. For more information, see the user example.
  • When you cannot recover the whole cluster because most machines in the cluster are permanently down, but you want to reuse the machines.

Use the tw_cluster_control command line tool with the --revert-to-standalone option on the machine you need to make standalone.

Removing all failed machines from the cluster 

You can do this by running tw_cluster_control from any running member of the cluster. The order of these steps is particularly important. See the note below.
  1. Log in to the appliance command line as the tideway user.
  2. Use tw_cluster_control to remove all failed machines from the cluster. You need to supply the password of the system user. Enter:
    [tideway@wilkoapp1 ~]$ tw_cluster_control --remove-broken
    Password:

    Found 1 broken member:
        Harness Cluster-03 (wilkoapp3.tideway.com)

    Are you sure you want to make these changes? (y/n) y

    1 member is being removed
    [tideway@wilkoapp1 ~]$
  3. Before you can reuse any machine removed from the cluster, you must revert it to a standalone configuration. All data is lost in this process. On the command line of the machine you want to revert, enter:
    tideway@wilkoapp3 ~]$ tw_cluster_control --revert-to-standalone
    Removing this machine from the current cluster

    WARNING: This will delete all data on this cluster member!

      Do you wish to proceed? (yes/no) yes
    Stopping Cluster Manager service:
    Stopping Cluster Manager service:                           [  FAILED  ]
    Removing cluster configuration
    Starting Cluster Manager service:
    Starting Cluster Manager service:                           [  OK  ]
    Removing appliance configuration
    Deleting datastore
    Starting Security service:                                  [  OK  ]
    ...

    ...
    Starting Reasoning service:                                 [  OK  ]
    Importing TKU packages:                                     [  Unknown  ]
    Writing TKU-Core-2064-02-1-ADDM-10.0+:                      [  OK  ]
    [ TKU-Extended-DB-Discovery-2064-02-1-ADDM-10.0+:           [  Unknown  ]
    [ TKU-Extended-Middleware-Discovery-2064-02-1-ADDM-10.0+:   [  Unknown  ]
    [ TKU-System-2064-02-1-ADDM-10.0+:                          [  Unknown  ]
    Activating patterns:                                        [  OK  ]
    Starting Tomcat:                                            [  OK  ]
    Starting Reports service:                                   [  OK  ]
    Starting Application Server service:                        [  OK  ]
    Updating cron tables:                                       [  OK  ]
    Updating baseline:                                          [  OK  ]
    Finished removing cluster configuration
    [tideway@wilkoapp3 ~]$
If a machine in the cluster has failed, and you --revert-to-standalone before removing it from the cluster, then you must shut down the reverted machine before issuing the --remove-broken command.

 

Tip: For faster searching, add an asterisk to the end of your partial query. Example: cert*