public PlacementGroupConfig withInstanceRole(InstanceRoleType instanceRole) {
        this.instanceRole = instanceRole.toString();
        return this;
    }
<p>
Role of the instance in the cluster.
</p>
<p>
Starting with Amazon EMR release 5.23.0, the only supported instance role is <code>MASTER</code>.
</p>

@param instanceRole
       Role of the instance in the cluster.</p>
       <p>
       Starting with Amazon EMR release 5.23.0, the only supported instance role is <code>MASTER</code>.
@return Returns a reference to this object so that method calls can be chained together.
@see InstanceRoleType
aws-java-sdk-emr/src/main/java/com/amazonaws/services/elasticmapreduce/model/PlacementGroupConfig.java