5.6. Verifying a Configuration

Once you have created your cluster configuration file, verify that it is running correctly by performing the following steps:

At each node, restart the cluster software. That action ensures that any configuration additions that are checked only at startup time are included in the running configuration. You can restart the cluster software by running service cman restart. For example:

[root@example-01 ~]# service cman restart
Stopping cluster: 
   Leaving fence domain...                                 [  OK  ]
   Stopping gfs_controld...                                [  OK  ]
   Stopping dlm_controld...                                [  OK  ]
   Stopping fenced...                                      [  OK  ]
   Stopping cman...                                        [  OK  ]
   Waiting for corosync to shutdown:                       [  OK  ]
   Unloading kernel modules...                             [  OK  ]
   Unmounting configfs...                                  [  OK  ]
Starting cluster: 
   Checking Network Manager...                             [  OK  ]
   Global setup...                                         [  OK  ]
   Loading kernel modules...                               [  OK  ]
   Mounting configfs...                                    [  OK  ]
   Starting cman...                                        [  OK  ]
   Waiting for quorum...                                   [  OK  ]
   Starting fenced...                                      [  OK  ]
   Starting dlm_controld...                                [  OK  ]
   Starting gfs_controld...                                [  OK  ]
   Unfencing self...                                       [  OK  ]
   Joining fence domain...                                 [  OK  ]

Run service clvmd start, if CLVM is being used to create clustered volumes. For example:

[root@example-01 ~]# service clvmd start
Activating VGs:                                            [  OK  ]

Run service gfs2 start, if you are using Red Hat GFS2. For example:

[root@example-01 ~]# service gfs2 start
Mounting GFS2 filesystem (/mnt/gfsA):                      [  OK  ]
Mounting GFS2 filesystem (/mnt/gfsB):                      [  OK  ]

Run service rgmanager start, if you using high-availability (HA) services. For example:

[root@example-01 ~]# service rgmanager start
Starting Cluster Service Manager:                          [  OK  ]

At any cluster node, run cman_tools nodes to verify that the nodes are functioning as members in the cluster (signified as "M" in the status column, "Sts"). For example:

[root@example-01 ~]# cman_tool nodes
Node  Sts   Inc   Joined               Name
   1   M    548   2010-09-28 10:52:21  node-01.example.com
   2   M    548   2010-09-28 10:52:21  node-02.example.com
   3   M    544   2010-09-28 10:52:21  node-03.example.com

At any node, using the clustat utility, verify that the HA services are running as expected. In addition, clustat displays status of the cluster nodes. For example:

[root@example-01 ~]#clustat
Cluster Status for mycluster @ Wed Nov 17 05:40:00 2010
Member Status: Quorate

 Member Name                             ID   Status
 ------ ----                             ---- ------
 node-03.example.com                         3 Online, rgmanager
 node-02.example.com                         2 Online, rgmanager
 node-01.example.com                         1 Online, Local, rgmanager

 Service Name                   Owner (Last)                   State         
 ------- ----                   ----- ------                   -----           
 service:example_apache         node-01.example.com            started       
 service:example_apache2        (none)                         disabled

If the cluster is running as expected, you are done with creating a configuration file. You can manage the cluster with command-line tools described in Chapter 6, Managing Red Hat High Availability Add-On With Command Line Tools.