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A Simple Apache Web Server HA Configuration

A common configuration for an HA server is simply to provide an IP address and a single service to be failed over[1]. This example will be an active/passive[2] configuration for the Apache web server.

Version 1 Configuration in /etc/ha.d/haresources

paul    1.2.3.4 apache

Version 2 Configuration in /var/lib/heartbeat/crm/cib.xml

<cib>
  <configuration>
    <crm_config/>
    <nodes/>
    <resources>
      <group id="apache_group">
        <primitive id="ip_resource_1" class="ocf" type="IPaddr" provider="heartbeat">
          <instance_attributes>
            <attributes>
              <nvpair name="ip" value="1.2.3.4"/>
            </attributes>
          </instance_attributes>
        </primitive>
        <primitive id="apache" class="heartbeat" type="apache"/>
      </group>
    </resources>
    <constraints>
      <rsc_location id="run_apache_group" rsc="apache_group">
        <rule id="pref_run_apache_group" score="100">
          <expression attribute="#uname" operation="eq" value="paul"/>
        </rule>
      </rsc_location>
    </constraints>
  </configuration>
  <status/>
</cib>

Explanation

Alternate Version 2 Configuration

<cib>
  <configuration>
    <crm_config/>
    <nodes/>
    <resources>
      <primitive id="ip_resource_1" class="ocf" type="IPaddr" provider="heartbeat">
        <instance_attributes>
          <attributes>
            <nvpair name="ip" value="1.2.3.4"/>
          </attributes>
        </instance_attributes>
      </primitive>
      <primitive id="apache" class="heartbeat" type="apache"/>
    </resources>
    <constraints>
      <rsc_location id="run_ip_resource_1" rsc="ip_resource_1">
        <rule id="pref_run_ip_resource_1" score="100">
          <expression attribute="#uname" operation="eq" value="paul"/>
        </rule>
      </rsc_location>
      <rsc_colocation id="same_apache_ip" from="ip_resource_1" to="apache" score="INFINITY"/>
    </constraints>
  </configuration>
  <status/>
</cib>

See Also

GettingStarted/Apache[3]

References

[1]http://en.wikipedia.org/wiki/Failover
[2]http://www.linux-ha.org/ActivePassive
[3]http://www.linux-ha.org/GettingStarted/Apache

This information provided courtesy of the Linux-HA project at http://linux-ha.org/