Chapter 9. Managing Red Hat High Availability Add-On With Command Line Tools

This chapter describes various administrative tasks for managing Red Hat High Availability Add-On and consists of the following sections:

Important

Make sure that your deployment of Red Hat High Availability Add-On meets your needs and can be supported. Consult with an authorized Red Hat representative to verify your configuration prior to deployment. In addition, allow time for a configuration burn-in period to test failure modes.

Important

This chapter references commonly used cluster.conf elements and attributes. For a comprehensive list and description of cluster.conf elements and attributes, see the cluster schema at /usr/share/cluster/cluster.rng, and the annotated schema at /usr/share/doc/cman-X.Y.ZZ/cluster_conf.html (for example /usr/share/doc/cman-3.0.12/cluster_conf.html).

Important

Certain procedure in this chapter call for using the cman_tool version -r command to propagate a cluster configuration throughout a cluster. Using that command requires that ricci is running.

Note

Procedures in this chapter, may include specific commands for some of the command-line tools listed in Appendix E, Command Line Tools Summary. For more information about all commands and variables, see the man page for each command-line tool.

9.1. Starting and Stopping the Cluster Software

You can start or stop cluster software on a node according to Section 9.1.1, “Starting Cluster Software” and Section 9.1.2, “Stopping Cluster Software”. Starting cluster software on a node causes it to join the cluster; stopping the cluster software on a node causes it to leave the cluster.

9.1.1. Starting Cluster Software

To start the cluster software on a node, type the following commands in this order:
  1. service cman start
  2. service clvmd start, if CLVM has been used to create clustered volumes
  3. service gfs2 start, if you are using Red Hat GFS2
  4. service rgmanager start, if you using high-availability (HA) services (rgmanager).
For example: 
[root@example-01 ~]# service cman start
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  ]
[root@example-01 ~]# service clvmd start
Starting clvmd:                                            [  OK  ]
Activating VG(s):   2 logical volume(s) in volume group "vg_example" now active
                                                           [  OK  ]
[root@example-01 ~]# service gfs2 start
Mounting GFS2 filesystem (/mnt/gfsA):                      [  OK  ]
Mounting GFS2 filesystem (/mnt/gfsB):                      [  OK  ]
[root@example-01 ~]# service rgmanager start
Starting Cluster Service Manager:                          [  OK  ]
[root@example-01 ~]#

9.1.2. Stopping Cluster Software

To stop the cluster software on a node, type the following commands in this order:
  1. service rgmanager stop, if you using high-availability (HA) services (rgmanager).
  2. service gfs2 stop, if you are using Red Hat GFS2
  3. umount -at gfs2, if you are using Red Hat GFS2 in conjunction with rgmanager, to ensure that any GFS2 files mounted during rgmanager startup (but not unmounted during shutdown) were also unmounted.
  4. service clvmd stop, if CLVM has been used to create clustered volumes
  5. service cman stop
For example: 
[root@example-01 ~]# service rgmanager stop
Stopping Cluster Service Manager:                          [  OK  ]
[root@example-01 ~]# service gfs2 stop
Unmounting GFS2 filesystem (/mnt/gfsA):                    [  OK  ]
Unmounting GFS2 filesystem (/mnt/gfsB):                    [  OK  ]
[root@example-01 ~]# umount -at gfs2
[root@example-01 ~]# service clvmd stop
Signaling clvmd to exit                                    [  OK  ]
clvmd terminated                                           [  OK  ]
[root@example-01 ~]# service cman stop
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  ]
[root@example-01 ~]#

Note

Stopping cluster software on a node causes its HA services to fail over to another node. As an alternative to that, consider relocating or migrating HA services to another node before stopping cluster software. For information about managing HA services, see Section 9.3, “Managing High-Availability Services”.