[jira] [Created] (HDFS-6536) FileSystem.Cache.closeAll() threw an exception due to authentication failure at the end of a webhdfs client session

["Yongjun Zhang (JIRA)" <ji...@apache.org>]

Yongjun Zhang created HDFS-6536:
-----------------------------------

             Summary: FileSystem.Cache.closeAll() threw an exception due to authentication failure at the end of a webhdfs client session
                 Key: HDFS-6536
                 URL: https://issues.apache.org/jira/browse/HDFS-6536
             Project: Hadoop HDFS
          Issue Type: Bug
          Components: hdfs-client, webhdfs
    Affects Versions: 2.4.0
            Reporter: Yongjun Zhang


With a small client program below, when running as user "root", exception is thrown at the end of the client run. The config is HA security enabled, with client config setting 
{code}
  <property>
    <name>fs.defaultFS</name>
    <value>webhdfs://ns1</value>
  </property>
{code}

The client program:

{code}
public class kclient1 {
	public static void main(String[] args) throws IOException {
	  final Configuration conf = new Configuration();
          //a non-root user
          final UserGroupInformation ugi = UserGroupInformation.getUGIFromTicketCache("/tmp/krb5cc_496", "hdfs@xyz.com");  

          System.out.println("Starting");
          ugi.doAs(new PrivilegedAction<Object>() {
	  @Override
	      public Object run() {
		  try {
		  	FileSystem fs = FileSystem.get(conf);			
		  	String renewer = "abcdefg";
		  	fs.addDelegationTokens(
		  			renewer, ugi.getCredentials());
		  	// Just to prove that we connected with right credentials.
		  	fs.getFileStatus(new Path("/"));
		  	return fs.getDelegationToken(renewer);
		  } catch (Exception e) {
		  	e.printStackTrace();
		  	return null;
                  }
           }
    });
    System.out.println("THE END");
  }
}		
{code}

Output:
{code}
[root@yjzc5w-1 tmp2]# hadoop --config /tmp2/conf jar kclient1.jar kclient1.kclient1
Starting
14/06/14 20:38:51 WARN ssl.FileBasedKeyStoresFactory: The property 'ssl.client.truststore.location' has not been set, no TrustStore will be loaded
14/06/14 20:38:52 INFO web.WebHdfsFileSystem: Retrying connect to namenode: yjzc5w-2.xyz.com/172.26.3.87:20101. Already tried 0 time(s); retry policy is org.apache.hadoop.io.retry.RetryPolicies$FailoverOnNetworkExceptionRetry@1a92210, delay 0ms.
To prove that connection with right credentials
to get file status updated updated 7
THE END
14/06/14 20:38:53 WARN ssl.FileBasedKeyStoresFactory: The property 'ssl.client.truststore.location' has not been set, no TrustStore will be loaded
14/06/14 20:38:53 WARN security.UserGroupInformation: PriviledgedActionException as:root (auth:KERBEROS) cause:java.io.IOException: org.apache.hadoop.security.authentication.client.AuthenticationException: GSSException: No valid credentials provided (Mechanism level: Failed to find any Kerberos tgt)
14/06/14 20:38:53 INFO fs.FileSystem: FileSystem.Cache.closeAll() threw an exception:
java.io.IOException: Authentication failed, url=http://yjzc5w-2.xyz.com:20101/webhdfs/v1/?op=CANCELDELEGATIONTOKEN&user.name=root&token=HAAEaGRmcwRoZGZzAIoBRp2bNByKAUbBp7gcbBQUD6vWmRYJRv03XZj7Jajf8PU8CB8SV0VCSERGUyBkZWxlZ2F0aW9uC2hhLWhkZnM6bnMx
[root@yjzc5w-1 tmp2]# 
{code}

We can see the the exception is thrown in the end of the client run.

I found that the problem is that at the end of client run, like the C++ destructor is called at the end of object scope, the tokens stored in the filesystem cache is get cancelled with the following all:

{code}
final class TokenAspect<T extends FileSystem & Renewable> {
  @InterfaceAudience.Private
  public static class TokenManager extends TokenRenewer {
    @Override
    public void cancel(Token<?> token, Configuration conf) throws IOException {
      getInstance(token, conf).cancelDelegationToken(token); <==
    }
{code}
where getInstance(token, conf) create a FileSystem as user "root", then call cancelDelegationToken to server side. However, server doesn't have "root" credential, so throw this exceptoin.

When I run the same program as user "hdfs", then it's fine.

I think if we run the call to cancelDelegationToken as the user who created the token intially ("hdfs" in this case), then it should work fine.
However, the information of the user who created the token is not available at that point. 

Hi [~daryn], I wonder if you could give a quick comment, really appreciate it!




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