8.7.2. Using Rules to Control Resource Defaults

⁠8.7.2. Using Rules to Control Resource Defaults

Rules can be used for resource and operation defaults. The following example illustrates how to set a different resource-stickiness value during and outside work hours. This allows resources to automatically move back to their most preferred hosts, but at a time that (in theory) does not interfere with business activities.

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Example 8.16. Change resource-stickiness during working hours

<rsc_defaults>
   <meta_attributes id="core-hours" score="2">
      <rule id="core-hour-rule" score="0">
        <date_expression id="nine-to-five-Mon-to-Fri" operation="date_spec">
          <date_spec id="nine-to-five-Mon-to-Fri-spec" hours="9-16" weekdays="1-5"/>
        </date_expression>
      </rule>
      <nvpair id="core-stickiness" name="resource-stickiness" value="INFINITY"/>
   </meta_attributes>
   <meta_attributes id="after-hours" score="1" >
      <nvpair id="after-stickiness" name="resource-stickiness" value="0"/>
   </meta_attributes>
</rsc_defaults>

Rules may be used similarly in instance_attributes or utilization blocks.

Any single block may directly contain only a single rule, but that rule may itself contain any number of rules.

rsc_expression and op_expression blocks may additionally be used to set defaults on either a single resource or across an entire class of resources with a single rule. rsc_expression may be used to select resource agents within both rsc_defaults and op_defaults, while op_expression may only be used within op_defaults. If multiple rules succeed for a given resource agent, the last one specified will be the one that takes effect. As with any other rule, boolean operations may be used to make more complicated expressions.

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Example 8.17. Set all IPaddr2 resources to stopped

<rsc_defaults>
    <meta_attributes id="op-target-role">
        <rule id="op-target-role-rule" score="INFINITY">
            <rsc_expression id="op-target-role-expr" class="ocf" provider="heartbeat"
              type="IPaddr2"/>
        </rule>
        <nvpair id="op-target-role-nvpair" name="target-role" value="Stopped"/>
    </meta_attributes>
</rsc_defaults>

⁠

Example 8.18. Set all monitor action timeouts to 7 seconds

<op_defaults>
    <meta_attributes id="op-monitor-defaults">
        <rule id="op-monitor-default-rule" score="INFINITY">
            <op_expression id="op-monitor-default-expr" name="monitor"/>
        </rule>
        <nvpair id="op-monitor-timeout" name="timeout" value="7s"/>
    </meta_attributes>
</op_defaults>

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Example 8.19. Set the monitor action timeout on all IPaddr2 resources with a given monitor interval to 8 seconds

<op_defaults>
    <meta_attributes id="op-monitor-and">
        <rule id="op-monitor-and-rule" score="INFINITY">
            <rsc_expression id="op-monitor-and-rsc-expr" class="ocf" provider="heartbeat"
              type="IPaddr2"/>
            <op_expression id="op-monitor-and-op-expr" name="monitor" interval="10s"/>
        </rule>
        <nvpair id="op-monitor-and-timeout" name="timeout" value="8s"/>
    </meta_attributes>
</op_defaults>