private static Predicate hostnameIs(String hostname) {
    return new EqualsPredicate<>(HOST_NAME, hostname);
  }
Creates a predicate in the form of:
<pre>component_name=... AND (host_name=... OR host_name=... OR ...)</pre>

@param componentName component name
@param hosts set of host names
ambari-server/src/main/java/org/apache/ambari/server/topology/addservice/ProvisionActionPredicateBuilder.java