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From Robert Metzger <rmetz...@apache.org>
Subject Re: Running continuously on yarn with kerberos
Date Thu, 05 Nov 2015 11:25:35 GMT
Hi Niels,
thank you for analyzing the issue so properly. I agree with you. It seems
that HDFS and HBase are using their own tokes which we need to transfer
from the client to the YARN containers. We should be able to port the fix
from Spark (which they got from Storm) into our YARN client.
I think we would add this in org.apache.flink.yarn.Utils#setTokensFor().

Do you want to implement and verify the fix yourself? If you are to busy at
the moment, we can also discuss how we share the work (I'm implementing it,
you test the fix)


Robert

On Tue, Nov 3, 2015 at 5:26 PM, Niels Basjes <Niels@basjes.nl> wrote:

> Update on the status so far.... I suspect I found a problem in a secure
> setup.
>
> I have created a very simple Flink topology consisting of a streaming
> Source (the outputs the timestamp a few times per second) and a Sink (that
> puts that timestamp into a single record in HBase).
> Running this on a non-secure Yarn cluster works fine.
>
> To run it on a secured Yarn cluster my main routine now looks like this:
>
> public static void main(String[] args) throws Exception {
>     System.setProperty("java.security.krb5.conf", "/etc/krb5.conf");
>     UserGroupInformation.loginUserFromKeytab("nbasjes@xxxxxx.NET", "/home/nbasjes/.krb/nbasjes.keytab");
>
>     final StreamExecutionEnvironment env = StreamExecutionEnvironment.getExecutionEnvironment();
>     env.setParallelism(1);
>
>     DataStream<String> stream = env.addSource(new TimerTicksSource());
>     stream.addSink(new SetHBaseRowSink());
>     env.execute("Long running Flink application");
> }
>
> When I run this
>      flink run -m yarn-cluster -yn 1 -yjm 1024 -ytm 4096
> ./kerberos-1.0-SNAPSHOT.jar
>
> I see after the startup messages:
>
> 17:13:24,466 INFO  org.apache.hadoop.security.UserGroupInformation
>       - Login successful for user nbasjes@xxxxxx.NET using keytab file
> /home/nbasjes/.krb/nbasjes.keytab
> 11/03/2015 17:13:25 Job execution switched to status RUNNING.
> 11/03/2015 17:13:25 Custom Source -> Stream Sink(1/1) switched to
> SCHEDULED
> 11/03/2015 17:13:25 Custom Source -> Stream Sink(1/1) switched to
> DEPLOYING
> 11/03/2015 17:13:25 Custom Source -> Stream Sink(1/1) switched to RUNNING
>
> Which looks good.
>
> However ... no data goes into HBase.
> After some digging I found this error in the task managers log:
>
> 17:13:42,677 WARN  org.apache.hadoop.hbase.ipc.RpcClient                         - Exception
encountered while connecting to the server : javax.security.sasl.SaslException: GSS initiate
failed [Caused by GSSException: No valid credentials provided (Mechanism level: Failed to
find any Kerberos tgt)]
> 17:13:42,677 FATAL org.apache.hadoop.hbase.ipc.RpcClient                         - SASL
authentication failed. The most likely cause is missing or invalid credentials. Consider 'kinit'.
> javax.security.sasl.SaslException: GSS initiate failed [Caused by GSSException: No valid
credentials provided (Mechanism level: Failed to find any Kerberos tgt)]
> 	at com.sun.security.sasl.gsskerb.GssKrb5Client.evaluateChallenge(GssKrb5Client.java:212)
> 	at org.apache.hadoop.hbase.security.HBaseSaslRpcClient.saslConnect(HBaseSaslRpcClient.java:177)
> 	at org.apache.hadoop.hbase.ipc.RpcClient$Connection.setupSaslConnection(RpcClient.java:815)
> 	at org.apache.hadoop.hbase.ipc.RpcClient$Connection.access$800(RpcClient.java:349)
>
>
> First starting a yarn-session and then loading my job gives the same error.
>
> My best guess at this point is that Flink needs the same fix as described
> here:
>
> https://issues.apache.org/jira/browse/SPARK-6918   (
> https://github.com/apache/spark/pull/5586 )
>
> What do you guys think?
>
> Niels Basjes
>
>
>
> On Tue, Oct 27, 2015 at 6:12 PM, Maximilian Michels <mxm@apache.org>
> wrote:
>
>> Hi Niels,
>>
>> You're welcome. Some more information on how this would be configured:
>>
>> In the kdc.conf, there are two variables:
>>
>>         max_life = 2h 0m 0s
>>         max_renewable_life = 7d 0h 0m 0s
>>
>> max_life is the maximum life of the current ticket. However, it may be
>> renewed up to a time span of max_renewable_life from the first ticket issue
>> on. This means that from the first ticket issue, new tickets may be
>> requested for one week. Each renewed ticket has a life time of max_life (2
>> hours in this case).
>>
>> Please let us know about any difficulties with long-running streaming
>> application and Kerberos.
>>
>> Best regards,
>> Max
>>
>> On Tue, Oct 27, 2015 at 2:46 PM, Niels Basjes <Niels@basjes.nl> wrote:
>>
>>> Hi,
>>>
>>> Thanks for your feedback.
>>> So I guess I'll have to talk to the security guys about having special
>>> kerberos ticket expiry times for these types of jobs.
>>>
>>> Niels Basjes
>>>
>>> On Fri, Oct 23, 2015 at 11:45 AM, Maximilian Michels <mxm@apache.org>
>>> wrote:
>>>
>>>> Hi Niels,
>>>>
>>>> Thank you for your question. Flink relies entirely on the Kerberos
>>>> support of Hadoop. So your question could also be rephrased to "Does
>>>> Hadoop support long-term authentication using Kerberos?". And the
>>>> answer is: Yes!
>>>>
>>>> While Hadoop uses Kerberos tickets to authenticate users with services
>>>> initially, the authentication process continues differently
>>>> afterwards. Instead of saving the ticket to authenticate on a later
>>>> access, Hadoop creates its own security tockens (DelegationToken) that
>>>> it passes around. These are authenticated to Kerberos periodically. To
>>>> my knowledge, the tokens have a life span identical to the Kerberos
>>>> ticket maximum life span. So be sure to set the maximum life span very
>>>> high for long streaming jobs. The renewal time, on the other hand, is
>>>> not important because Hadoop abstracts this away using its own
>>>> security tockens.
>>>>
>>>> I'm afraid there is not Kerberos how-to yet. If you are on Yarn, then
>>>> it is sufficient to authenticate the client with Kerberos. On a Flink
>>>> standalone cluster you need to ensure that, initially, all nodes are
>>>> authenticated with Kerberos using the kinit tool.
>>>>
>>>> Feel free to ask if you have more questions and let us know about any
>>>> difficulties.
>>>>
>>>> Best regards,
>>>> Max
>>>>
>>>>
>>>>
>>>> On Thu, Oct 22, 2015 at 2:06 PM, Niels Basjes <Niels@basjes.nl> wrote:
>>>> > Hi,
>>>> >
>>>> > I want to write a long running (i.e. never stop it) streaming flink
>>>> > application on a kerberos secured Hadoop/Yarn cluster. My application
>>>> needs
>>>> > to do things with files on HDFS and HBase tables on that cluster so
>>>> having
>>>> > the correct kerberos tickets is very important. The stream is to be
>>>> ingested
>>>> > from Kafka.
>>>> >
>>>> > One of the things with Kerberos is that the tickets expire after a
>>>> > predetermined time. My knowledge about kerberos is very limited so I
>>>> hope
>>>> > you guys can help me.
>>>> >
>>>> > My question is actually quite simple: Is there an howto somewhere on
>>>> how to
>>>> > correctly run a long running flink application with kerberos that
>>>> includes a
>>>> > solution for the kerberos ticket timeout  ?
>>>> >
>>>> > Thanks
>>>> >
>>>> > Niels Basjes
>>>>
>>>
>>>
>>>
>>> --
>>> Best regards / Met vriendelijke groeten,
>>>
>>> Niels Basjes
>>>
>>
>>
>
>
> --
> Best regards / Met vriendelijke groeten,
>
> Niels Basjes
>

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