Mine

<Context>

    <!-- Default set of monitored resources -->
    <WatchedResource>WEB-INF/web.xml</WatchedResource>

    <Realm className="org.apache.catalina.realm.JNDIRealm" 
      connectionURL="ldaps://ldap.its.carleton.edu:636"
      userPattern="carlnetid={0},ou=People, dc=carleton, dc=edu" 
      userRoleName="objectclass"
      />

    <Valve className="org.apache.catalina.valves.AccessLogValve"
        prefix="shibboleth_access_log." suffix=".txt"
        directory="/tmp/"
        pattern="common"/>
	
    <!-- Uncomment this to disable session persistence across Tomcat restarts -->
    <!--
    <Manager pathname="" />
    -->

</Context>