5.6. Instance Attributes

The scripts of some resource classes (LSB not being one of them) can be given parameters which determine how they behave and which instance of a service they control.

If your resource agent supports parameters, you can add them with the crm_resource command. For instance

# crm_resource --resource Public-IP --set-parameter ip --property-value 1.2.3.4

would create an entry in the resource like this:

Example 5.4. An example OCF resource with instance attributes

<primitive id="Public-IP" class="ocf" type="IPaddr" provider="heartbeat">
   <instance_attributes id="params-public-ip">
      <nvpair id="public-ip-addr" name="ip" value="1.2.3.4"/>
   </instance_attributes>
</primitive>

For an OCF resource, the result would be an environment variable called OCF_RESKEY_ip with a value of 1.2.3.4.

The list of instance attributes supported by an OCF script can be found by calling the resource script with the meta-data command. The output contains an XML description of all the supported attributes, their purpose and default values.

Example 5.5. Displaying the metadata for the Dummy resource agent template

# export OCF_ROOT=/usr/lib/ocf
# $OCF_ROOT/resource.d/pacemaker/Dummy meta-data

<?xml version="1.0"?>
  <!DOCTYPE resource-agent SYSTEM "ra-api-1.dtd">
  <resource-agent name="Dummy" version="0.9">
    <version>1.0</version>

    <longdesc lang="en-US">
      This is a Dummy Resource Agent. It does absolutely nothing except
      keep track of whether its running or not.
      Its purpose in life is for testing and to serve as a template for RA writers.
    </longdesc>
    <shortdesc lang="en-US">Dummy resource agent</shortdesc>

    <parameters>
      <parameter name="state" unique="1">
        <longdesc lang="en-US">
          Location to store the resource state in.
        </longdesc>
        <shortdesc lang="en-US">State file</shortdesc>
        <content type="string" default="/var/run/Dummy-{OCF_RESOURCE_INSTANCE}.state" />
      </parameter>

      <parameter name="dummy" unique="0">
        <longdesc lang="en-US">
          Dummy attribute that can be changed to cause a reload
        </longdesc>
        <shortdesc lang="en-US">Dummy attribute that can be changed to cause a reload</shortdesc>
        <content type="string" default="blah" />
      </parameter>
    </parameters>

    <actions>
      <action name="start"        timeout="90" />
      <action name="stop"         timeout="100" />
      <action name="monitor"      timeout="20" interval="10",height="0" start-delay="0" />
      <action name="reload"       timeout="90" />
      <action name="migrate_to"   timeout="100" />
      <action name="migrate_from" timeout="90" />
      <action name="meta-data"    timeout="5" />
      <action name="validate-all" timeout="30" />
    </actions>
  </resource-agent>