KNOX SSO issues

[Prasad R. Nuamatha]

We have used the following document  and my security team was able to 
create the identity asserter for site minder for federated authentication. 


https://cwiki.apache.org/confluence/display/KNOX/2015/12/18/Adding+a+Federation+Provider+to+Apache+Knox


When I am trying to use it I get the following error where it complains 
the configuration file missing.  I have atttached the configuration file, 
if someone could please let me know where i am going wrong it will be 
greatly helpful. 


2016-06-01 15:00:59,454 ERROR hadoop.gateway 
(GatewayServlet.java:service(126)) - Gateway processing failed: 
javax.servlet.ServletException: 
org.apache.shiro.subject.ExecutionException: 
java.security.PrivilegedActionException: javax.servlet.ServletException: 
java.lang.RuntimeException: java.lang.RuntimeException: PL00017: 
Configuration File missing:null
javax.servlet.ServletException: 
org.apache.shiro.subject.ExecutionException: 
java.security.PrivilegedActionException: javax.servlet.ServletException: 
java.lang.RuntimeException: java.lang.RuntimeException: PL00017: 
Configuration File missing:null
        at 
org.apache.shiro.web.servlet.AdviceFilter.cleanup(AdviceFilter.java:196)
        at 
org.apache.shiro.web.filter.authc.AuthenticatingFilter.cleanup(AuthenticatingFilter.java:155)

My configuration file 

<topology>

    <gateway>

        <provider>
            <role>authentication</role>
            <name>ShiroProvider</name>
            <enabled>true</enabled>
            <param>
                             <name>sessionTimeout</name>
                <value>30</value>
            </param>
            <param>
                <name>main.ldapRealm</name>
 <value>org.apache.hadoop.gateway.shirorealm.KnoxLdapRealm</value>
            </param>
            <param>
                <name>main.ldapContextFactory</name>
 
<value>org.apache.hadoop.gateway.shirorealm.KnoxLdapContextFactory</value>
            </param>
            <param>
                <name>main.ldapRealm.contextFactory</name>
                <value>$ldapContextFactory</value>
            </param>

              <param>
                        <name>main.ldapRealm.userDnTemplate</name>
                        <value>cn={0},ou=***,o=**</value>
                    </param>
                    <param>
                        <name>main.ldapRealm.contextFactory.url</name>
                        <value>ldap://***:389</value>
                    </param>

            <param>
 <name>main.ldapRealm.contextFactory.authenticationMechanism</name>
                <value>simple</value>
            </param>

            <param>
                <name>urls./**</name>
                <value>authcBasic</value>
            </param>

        </provider>

       <provider>
           <role>federation</role>
           <name>SiteMinder Identity Asserter</name>
           <enabled>true</enabled>
       </provider>



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