RHEL 6 Cluster Admin - 5.5.2. Adding a Cluster Service to the Cluster

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5.5.2. Adding a Cluster Service to the Cluster

To add a cluster service to the cluster, follow the steps in this section.

Open /etc/cluster/cluster.conf at any node in the cluster.

Add a service section within the rm element for each service. For example:


    <rm>
        <service autostart="1" domain="" exclusive="0" name="" recovery="restart">

        </service>
    </rm>

Configure the following parameters (attributes) in the service element:
- autostart — Specifies whether to autostart the service when the cluster starts.
- domain — Specifies a failover domain (if required).
- exclusive — Specifies a policy wherein the service only runs on nodes that have no other services running on them.
- recovery — Specifies a recovery policy for the service. The options are to relocate, restart, or disable the service.

Depending on the type of resources you want to use, populate the service with global or service-specific resources

For example, here is an Apache service that uses global resources:


    <rm>
        <resources>
                <fs name="web_fs" device="/dev/sdd2" mountpoint="/var/www" fstype="ext3"/>
                <ip address="127.143.131.100" monitor_link="on" sleeptime="10"/>
                <apache config_file="conf/httpd.conf" name="example_server" server_root="/etc/httpd" shutdown_wait="0"/>
        </resources>
        <service autostart="1" domain="example_pri" exclusive="0" name="example_apache" recovery="relocate">
                <fs ref="web_fs"/>
                <ip ref="127.143.131.100"/>
                <apache ref="example_server"/>
        </service>
    </rm>

For example, here is an Apache service that uses service-specific resources:


    <rm>
        <service autostart="0" domain="example_pri" exclusive="0" name="example_apache2" recovery="relocate">
                <fs name="web_fs2" device="/dev/sdd3" mountpoint="/var/www2" fstype="ext3"/>
                <ip address="127.143.131.101" monitor_link="on" sleeptime="10"/>
                <apache config_file="conf/httpd.conf" name="example_server2" server_root="/etc/httpd" shutdown_wait="0"/>
        </service>
    </rm>

Example 5.10, “cluster.conf with Services Added: One Using Global Resources and One Using Service-Specific Resources ” shows an example of a cluster.conf file with two services:

example_apache — This service uses global resources web_fs, 127.143.131.100, and example_server.
example_apache2 — This service uses service-specific resources web_fs2, 127.143.131.101, and example_server2.

Update the config_version attribute by incrementing its value (for example, changing from config_version="2" to config_version="3">).
Save /etc/cluster/cluster.conf.
(Optional) Validate the updated file against the cluster schema (cluster.rng) by running the ccs_config_validate command. For example:
```
[root@example-01 ~]# ccs_config_validate 
Configuration validates
```
Run the cman_tool version -r command to propagate the configuration to the rest of the cluster nodes.
Verify that the updated configuration file has been propagated.
Proceed to Section 5.6, “Verifying a Configuration”.

Example 5.10. `cluster.conf` with Services Added: One Using Global Resources and One Using Service-Specific Resources


<cluster name="mycluster" config_version="3">
   <clusternodes>
     <clusternode name="node-01.example.com" nodeid="1">
         <fence>
            <method name="APC">
              <device name="apc" port="1"/>
             </method>
         </fence>
     </clusternode>
     <clusternode name="node-02.example.com" nodeid="2">
         <fence>
            <method name="APC">
              <device name="apc" port="2"/>
            </method>
         </fence>
     </clusternode>
     <clusternode name="node-03.example.com" nodeid="3">
         <fence>
            <method name="APC">
              <device name="apc" port="3"/>
            </method>
         </fence>
     </clusternode>
   </clusternodes>
   <fencedevices>
         <fencedevice agent="fence_apc" ipaddr="apc_ip_example" login="login_example" name="apc" passwd="password_example"/>
   </fencedevices>
   <rm>
       <failoverdomains>
           <failoverdomain name="example_pri" nofailback="0" ordered="1" restricted="0">
               <failoverdomainnode name="node-01.example.com" priority="1"/>
               <failoverdomainnode name="node-02.example.com" priority="2"/>
               <failoverdomainnode name="node-03.example.com" priority="3"/>
           </failoverdomain>
       </failoverdomains>
       <resources>
           <fs name="web_fs" device="/dev/sdd2" mountpoint="/var/www" fstype="ext3"/>
           <ip address="127.143.131.100" monitor_link="on" sleeptime="10"/>
           <apache config_file="conf/httpd.conf" name="example_server" server_root="/etc/httpd" shutdown_wait="0"/>
       </resources>
       <service autostart="1" domain="example_pri" exclusive="0" name="example_apache" recovery="relocate">
           <fs ref="web_fs"/>
           <ip ref="127.143.131.100"/>
           <apache ref="example_server"/>
       </service>
       <service autostart="0" domain="example_pri" exclusive="0" name="example_apache2" recovery="relocate">
           <fs name="web_fs2" device="/dev/sdd3" mountpoint="/var/www2" fstype="ext3"/>
           <ip address="127.143.131.101" monitor_link="on" sleeptime="10"/>
           <apache config_file="conf/httpd.conf" name="example_server2" server_root="/etc/httpd" shutdown_wait="0"/>
       </service>
   </rm>
</cluster>

5.5.2. Adding a Cluster Service to the Cluster

Example 5.10. cluster.conf with Services Added: One Using Global Resources and One Using Service-Specific Resources

Example 5.10. `cluster.conf` with Services Added: One Using Global Resources and One Using Service-Specific Resources