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https://issues.apache.org/jira/browse/HDFS-13040?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16361857#comment-16361857
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Xiao Chen edited comment on HDFS-13040 at 2/13/18 11:06 PM:
------------------------------------------------------------

Worked on the test based on [~pifta]'s original. 

I think one thing that worths clarifying with Istvan is that, in the test the 
UGI is just the setting up the client, for doing an NN RPC. So if I understand 
correctly, what you observed from tests are all RPC behavior. The bug here is 
after the client authenticates with NN, when the NN is doing its part to get 
the edits.... see below

After some debugging, it seems this needs extra efforts to make a real test 
that lets NN read the edits via {{EditLogFileInputStream$URLLog}}. Currently 
{{DFSInotifyEventInputStream#poll}} would end up making the NN go the 
{{EditLogFileInputStream$FileLog}}, hence not triggering the authentication 
path reported. On the other hand, we can't really unit test the stream, since 
we do need the context of a NN RPC, and the context of NN loginuser. Will 
continue working on this when I can find cycles....

[~daryn] / [~kihwal],
Does the fix itself make sense to you?


was (Author: xiaochen):
Worked on the test based on [~pifta]'s original. 

I think one thing that worths clarifying with Istvan is that, in the test the 
UGI is just the setting up the client, for doing an NN RPC. So if I understand 
correctly, what you observed from tests are all RPC behavior. The bug here is 
after the client authenticates with NN, when the NN is doing its part to get 
the edits.... see below

After some debugging, it seems this needs extra efforts to make a real test 
that lets NN read the edits via {{EditLogFileInputStream$URLLog}}. Currently 
{{DFSInotifyEventInputStream#poll}} would end up making the NN go the 
{{EditLogFileInputStream$FileLog}}, hence not triggering the authentication 
path reported. On the other hand, we can really unit test the stream, since we 
do need the context of a NN RPC, and the context of NN loginuser. Will continue 
working on this when I can find cycles....

[~daryn] / [~kihwal],
Does the fix itself make sense to you?

> Kerberized inotify client fails despite kinit properly
> ------------------------------------------------------
>
>                 Key: HDFS-13040
>                 URL: https://issues.apache.org/jira/browse/HDFS-13040
>             Project: Hadoop HDFS
>          Issue Type: Bug
>          Components: namenode
>    Affects Versions: 2.6.0
>         Environment: Kerberized, HA cluster, iNotify client, CDH5.10.2
>            Reporter: Wei-Chiu Chuang
>            Assignee: Wei-Chiu Chuang
>            Priority: Major
>         Attachments: HDFS-13040.001.patch, HDFS-13040.02.patch, 
> HDFS-13040.half.test.patch, TestDFSInotifyEventInputStreamKerberized.java, 
> TransactionReader.java
>
>
> This issue is similar to HDFS-10799.
> HDFS-10799 turned out to be a client side issue where client is responsible 
> for renewing kerberos ticket actively.
> However we found in a slightly setup even if client has valid Kerberos 
> credentials, inotify still fails.
> Suppose client uses principal h...@example.com, 
>  namenode 1 uses server principal hdfs/nn1.example....@example.com
>  namenode 2 uses server principal hdfs/nn2.example....@example.com
> *After Namenodes starts for longer than kerberos ticket lifetime*, the client 
> fails with the following error:
> {noformat}
> 18/01/19 11:23:02 WARN security.UserGroupInformation: 
> PriviledgedActionException as:h...@gce.cloudera.com (auth:KERBEROS) 
> cause:org.apache.hadoop.ipc.RemoteException(java.io.IOException): We 
> encountered an error reading 
> https://nn2.example.com:8481/getJournal?jid=ns1&segmentTxId=8662&storageInfo=-60%3A353531113%3A0%3Acluster3,
>  
> https://nn1.example.com:8481/getJournal?jid=ns1&segmentTxId=8662&storageInfo=-60%3A353531113%3A0%3Acluster3.
>   During automatic edit log failover, we noticed that all of the remaining 
> edit log streams are shorter than the current one!  The best remaining edit 
> log ends at transaction 8683, but we thought we could read up to transaction 
> 8684.  If you continue, metadata will be lost forever!
>         at 
> org.apache.hadoop.hdfs.server.namenode.RedundantEditLogInputStream.nextOp(RedundantEditLogInputStream.java:213)
>         at 
> org.apache.hadoop.hdfs.server.namenode.EditLogInputStream.readOp(EditLogInputStream.java:85)
>         at 
> org.apache.hadoop.hdfs.server.namenode.NameNodeRpcServer.readOp(NameNodeRpcServer.java:1701)
>         at 
> org.apache.hadoop.hdfs.server.namenode.NameNodeRpcServer.getEditsFromTxid(NameNodeRpcServer.java:1763)
>         at 
> org.apache.hadoop.hdfs.server.namenode.AuthorizationProviderProxyClientProtocol.getEditsFromTxid(AuthorizationProviderProxyClientProtocol.java:1011)
>         at 
> org.apache.hadoop.hdfs.protocolPB.ClientNamenodeProtocolServerSideTranslatorPB.getEditsFromTxid(ClientNamenodeProtocolServerSideTranslatorPB.java:1490)
>         at 
> org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos$ClientNamenodeProtocol$2.callBlockingMethod(ClientNamenodeProtocolProtos.java)
>         at 
> org.apache.hadoop.ipc.ProtobufRpcEngine$Server$ProtoBufRpcInvoker.call(ProtobufRpcEngine.java:617)
>         at org.apache.hadoop.ipc.RPC$Server.call(RPC.java:1073)
>         at org.apache.hadoop.ipc.Server$Handler$1.run(Server.java:2216)
>         at org.apache.hadoop.ipc.Server$Handler$1.run(Server.java:2212)
>         at java.security.AccessController.doPrivileged(Native Method)
>         at javax.security.auth.Subject.doAs(Subject.java:415)
>         at 
> org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1920)
>         at org.apache.hadoop.ipc.Server$Handler.run(Server.java:2210)
> {noformat}
> Typically if NameNode has an expired Kerberos ticket, the error handling for 
> the typical edit log tailing would let NameNode to relogin with its own 
> Kerberos principal. However, when inotify uses the same code path to retrieve 
> edits, since the current user is the inotify client's principal, unless 
> client uses the same principal as the NameNode, NameNode can't do it on 
> behalf of the client.
> Therefore, a more appropriate approach is to use proxy user so that NameNode 
> can retrieving edits on behalf of the client.
> I will attach a patch to fix it. This patch has been verified to work for a 
> CDH5.10.2 cluster, however it seems impossible to craft a unit test for this 
> fix because the way Hadoop UGI handles Kerberos credentials (I can't have a 
> single process that logins as two Kerberos principals simultaneously and let 
> them establish connection)
> A possible workaround is for the inotify client to use the active NameNode's 
> server principal. However, that's not going to work when there's a namenode 
> failover, because then the client's principal will not be consistent with the 
> active NN's one, and then fails to authenticate.
> Credit: this bug was confirmed and reproduced by [~pifta] and [~r1pp3rj4ck]



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