Home | About | Sematext search-lucene.com search-hadoop.com
 Search Hadoop and all its subprojects:

Switch to Threaded View
MapReduce >> mail # user >> Re: Namenode going to safe mode on YARN


Copy link to this message
-
Re: Namenode going to safe mode on YARN
Hi Nithin & Ted,

  Thanks for the replies.

 I don't know what my replication factor is, I don't seem to have set
anything in my configuration files. I run on a single node cluster. My data
node has gone down and came back, and also I didn't delete any of the hdfs
blocks.

 I know that name node enter safe mode when HDFS is restarted, and will
leave soon. Is it safe to execute command to leave safe mode? I mean, can
something wrong happen if we do it ourselves? because it wouldn't have
collected the needed data and could not leave the safe mode by itself?

  And, does the error I gave above indicate some clue as to what I could do
better?

Thanks,
Kishore

On Mon, May 6, 2013 at 2:56 PM, Ted Xu <[EMAIL PROTECTED]> wrote:

> Hi Kishore,
>
> It should not be a bug. After restarting HDFS, namenode will enter safe
> mode until all needed data is collected. During safe mode, all update
> operations will fail.
>
> In some cases, as Nitin mentioned, namenode will never leave safe mode
> because it can't get enough data. In that case you may need to force name
> node leave safe mode.
>
> For more information, see
> http://hadoop.apache.org/docs/r2.0.4-alpha/hadoop-project-dist/hadoop-hdfs/HdfsUserGuide.html#Safemode
> .
>
>
> On Mon, May 6, 2013 at 5:00 PM, Nitin Pawar <[EMAIL PROTECTED]>wrote:
>
>> What is your replication factor on hdfs?
>> Did any of your datanode go down recently and is not back in rotation?
>> Did you delete any hdfs blocks directly from datanodes?
>> On May 6, 2013 2:28 PM, "Krishna Kishore Bonagiri" <
>> [EMAIL PROTECTED]> wrote:
>>
>>> Hi,
>>>
>>>   I have been running application on my YARN cluster since around 20
>>> days, about 5000 applications a day. I am getting the following error
>>> today. Please let me know how can I avoid this, is this happening because
>>> of a bug?
>>>
>>> org.apache.hadoop.ipc.RemoteException(org.apache.hadoop.hdfs.server.namenode.SafeModeException):
>>> Cannot create file/1066/AppMaster.jar. Name node is in safe mode.
>>> The reported blocks 4775 needs additional 880 blocks to reach the
>>> threshold 0.9990 of total blocks 5660. Safe mode will be turned off
>>> automatically.
>>>         at
>>> org.apache.hadoop.hdfs.server.namenode.FSNamesystem.startFileInternal(FSNamesystem.java:1786)
>>>         at
>>> org.apache.hadoop.hdfs.server.namenode.FSNamesystem.startFileInt(FSNamesystem.java:1737)
>>>         at
>>> org.apache.hadoop.hdfs.server.namenode.FSNamesystem.startFile(FSNamesystem.java:1719)
>>>         at
>>> org.apache.hadoop.hdfs.server.namenode.NameNodeRpcServer.create(NameNodeRpcServer.java:429)
>>>          at
>>> org.apache.hadoop.hdfs.protocolPB.ClientNamenodeProtocolServerSideTranslatorPB.create(ClientNamenodeProtocolServerSideTranslatorPB.java:271)
>>>         at
>>> org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos$ClientNamenodeProtocol$2.callBlockingMethod(ClientNamenodeProtocolProtos.java:40732)
>>>         at
>>> org.apache.hadoop.ipc.ProtobufRpcEngine$Server$ProtoBufRpcInvoker.call(ProtobufRpcEngine.java:454)
>>>         at org.apache.hadoop.ipc.RPC$Server.call(RPC.java:1014)
>>>         at org.apache.hadoop.ipc.Server$Handler$1.run(Server.java:1741)
>>>         at org.apache.hadoop.ipc.Server$Handler$1.run(Server.java:1737)
>>>         at java.security.AccessController.doPrivileged(Native Method)
>>>         at javax.security.auth.Subject.doAs(Subject.java:415)
>>>         at
>>> org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1478)
>>>         at org.apache.hadoop.ipc.Server$Handler.run(Server.java:1735)
>>>
>>>
>>> Thanks,
>>> Kishore
>>>
>>
>
>
> --
> Regards,
> Ted Xu
>