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10.3.8. Which Resource Instance is Promoted

During the start operation, most resource agents should call the crm_master utility. This tool automatically detects both the resource and host and should be used to set a preference for being promoted. Based on this, master-max, and master-node-max, the instance(s) with the highest preference will be promoted.
An alternative is to create a location constraint that indicates which nodes are most preferred as masters.

Example 10.11. Explicitly preferring node1 to be promoted to master

<rsc_location id="master-location" rsc="myMasterRsc">
    <rule id="master-rule" score="100" role="Master">
      <expression id="master-exp" attribute="#uname" operation="eq" value="node1"/>