Reverting a cluster member into a standalone machine

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 ~]$