Namenode going to safe mode on YARN

[Krishna Kishore Bonagiri]

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