8.5.2. Adding a Cluster Service to the Cluster
To add a cluster service to the cluster, follow the steps in this section.
Note
The examples provided in this section show a cluster service in which all of the resources are at the same level. For information on defining a service in which there is a dependency chain in a resource hierarchy, as well as the rules that govern the behavior of parent and child resources, see Appendix C, HA Resource Behavior.
- Open
/etc/cluster/cluster.confat any node in the cluster. - Add a
servicesection within thermelement for each service. For example:<rm> <service autostart="1" domain="" exclusive="0" name="" recovery="restart"> </service> </rm> - Configure the following parameters (attributes) in the
serviceelement:autostart— Specifies whether to autostart the service when the cluster starts. Use '1' to enable and '0' to disable; the default is enabled.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, disable, or restart-disable the service.
- Depending on the type of resources you want to use, populate the service with global or service-specific resourcesFor 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="yes" 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="yes" sleeptime="10"/> <apache config_file="conf/httpd.conf" name="example_server2" server_root="/etc/httpd" shutdown_wait="0"/> </service> </rm>Example 8.10, “cluster.confwith Services Added: One Using Global Resources and One Using Service-Specific Resources ” shows an example of acluster.conffile with two services:example_apache— This service uses global resourcesweb_fs,127.143.131.100, andexample_server.example_apache2— This service uses service-specific resourcesweb_fs2,127.143.131.101, andexample_server2.
- Update the
config_versionattribute by incrementing its value (for example, changing fromconfig_version="2"toconfig_version="3">). - Save
/etc/cluster/cluster.conf. - (Optional) Validate the updated file against the cluster schema (
cluster.rng) by running theccs_config_validatecommand. For example:[root@example-01 ~]#
ccs_config_validateConfiguration validates - Run the
cman_tool version -rcommand to propagate the configuration to the rest of the cluster nodes. - Verify that the updated configuration file has been propagated.
- Proceed to Section 8.9, “Verifying a Configuration”.
Example 8.10. 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="yes" 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="yes" sleeptime="10"/>
<apache config_file="conf/httpd.conf" name="example_server2" server_root="/etc/httpd" shutdown_wait="0"/>
</service>
</rm>
</cluster>
