Namenode not getting started

Question

I was using Hadoop in a pseudo-distributed mode and everything was working fine  But then I had to restart my computer because of some reason  And now when I am trying to start Namenode and Datanode I can find only Datanode running  Could anyone tell me the possible reason of this problem  Or am I doing something wrong   I tried both bin start-all sh and bin start-dfs sh

User · Answer

Open a new terminal and start the namenode using path-to-your-hadoop-install bin hadoop namenode  The check using jps and namenode should be running

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In core-site xml         lt configuration gt          lt property gt             lt name gt fs defaultFS lt  name gt             lt value gt hdfs   localhost 9000 lt  value gt          lt  property gt          lt property gt             lt name gt hadoop tmp dir lt  name gt             lt value gt  home yourusername hadoop tmp hadoop-  user name            lt  value gt     lt  property gt   lt  configuration gt    and format of namenode with    hdfs namenode -format  worked for hadoop 2 8 1

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After deleting a resource managers  data folder  the problem is gone  Even if you have formatting cannot solve this problem

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Add hadoop tmp dir property in core-site xml   lt configuration gt     lt property gt       lt name gt fs defaultFS lt  name gt       lt value gt hdfs   localhost 9000 lt  value gt     lt  property gt     lt property gt       lt name gt hadoop tmp dir lt  name gt       lt value gt  home yourname hadoop tmp hadoop-  user name  lt  value gt     lt  property gt   lt  configuration gt    and format hdfs  hadoop 2 7 1      hdfs namenode -format   The default value in core-default xml is  tmp hadoop-  user name   which will be deleted after reboot

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For me the following worked after I changed the directory of the namenode  and datanode in hdfs-site xml  -- before executing the following steps stop all services with stop-all sh or in my case I used the stop-dfs sh to stop the dfs   On the new configured directory  for every node  namenode and datanode   delete every folder files inside it  in my case a  current  directory   delete the Hadoop temporary directory   rm -rf  tmp haddop- USER   format the Namenode  hadoop bin hdfs namenode -format start-dfs sh   After I followed those steps my namenode and datanodes were alive using the new configured directory

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Try this   1  Stop all hadoop processes   stop-all sh  2  Remove the tmp folder manually  3  Format namenode   hadoop namenode -format  4  Start all processes   start-all sh

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If anyone using hadoop1 2 1 version and not able to run namenode  go to core-site xml  and change dfs default name to fs default name    And then format the namenode using  hadoop namenode -format   Finally run the hdfs using start-dfs sh and check for service using jps

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I ran into the same thing after a restart   for hadoop-2 7 3 all I had to do was format the namenode    lt HadoopRootDir gt  bin hdfs namenode -format   Then a jps command shows  6097 DataNode 755 RemoteMavenServer 5925 NameNode 6293 SecondaryNameNode 6361 Jps

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Did you change conf hdfs-site xml dfs name dir   Format namenode after you change it     bin hadoop namenode -format   bin hadoop start-all sh

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Instead of formatting namenode  may be you can use the below command to restart the namenode  It worked for me   sudo service hadoop-master restart   hadoop dfsadmin -safemode leave

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I ran  hadoop namenode to start namenode manually at foreground   From the logs I figured out that 50070 is ocuupied  which was defaultly used by dfs namenode http-address  After configuring dfs namenode http-address in hdfs-site xml  everything went well

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In conf hdfs-site xml  you should have a property like   lt property gt       lt name gt dfs name dir lt  name gt       lt value gt  home user hadoop name data lt  value gt   lt  property gt    The property  dfs name dir  allows you to control where Hadoop writes NameNode metadata   And giving it another dir rather than  tmp makes sure the NameNode data isn t being deleted when you reboot

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I was facing the issue of namenode not starting  I found a solution using following    first delete all contents from temporary folder  rm -Rf  lt tmp dir gt   my was  usr local hadoop tmp  format the namenode  bin hadoop namenode -format start all processes again bin start-all sh   You may consider rolling back as well using checkpoint  if you had it enabled

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If your namenode is stuck in safemode you can ssh to namenode  su hdfs user and run the following command to turn off safemode    hdfs dfsadmin -fs hdfs   server com 8020 -safemode leave

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I got the solution just share with you that will work who got the errors   1  First check the  home hadoop etc hadoop path  hdfs-site xml and   check the path of namenode and datanode    lt property gt     lt name gt dfs name dir lt  name gt       lt value gt file    home hadoop hadoopdata hdfs namenode lt  value gt   lt  property gt    lt property gt     lt name gt dfs data dir lt  name gt       lt value gt file    home hadoop hadoopdata hdfs datanode lt  value gt   lt  property gt   2 Check the permission group and user of namenode and datanode of the particular path  home hadoop hadoopdata hdfs datanode   and check if there are any problems in all of them and if there are any mismatch then correct it  ex  chown -R hadoop hadoop in use lock  change user and group  chmod -R 755  lt file name gt  for change the permission

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hadoop tmp dir in the core-site xml is defaulted to  tmp hadoop-  user name  which is cleaned after every reboot  Change this to some other directory which doesn t get cleaned on reboot

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If you facing this issue after rebooting the system  Then below steps will work fine   For workaround   1  format the namenode  bin hadoop namenode -format  2  start all processes again bin start-all sh  For Perm fix  -  1  go to   conf core-site xml change fs default name to your custom one   2  format the namenode  bin hadoop namenode -format  3  start all processes again bin start-all sh

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Following STEPS worked for me with hadoop 2 2 0    STEP 1 stop hadoop  hduser prayagupd   usr local hadoop-2 2 0 sbin stop-dfs sh   STEP 2 remove tmp folder  hduser prayagupd  sudo rm -rf  app hadoop tmp    STEP 3 create  app hadoop tmp   hduser prayagupd  sudo mkdir -p  app hadoop tmp hduser prayagupd  sudo chown hduser hadoop  app hadoop tmp hduser prayagupd  sudo chmod 750  app hadoop tmp   STEP 4 format namenode  hduser prayagupd  hdfs namenode -format   STEP 5 start dfs  hduser prayagupd   usr local hadoop-2 2 0 sbin start-dfs sh   STEP 6 check jps  hduser prayagupd    jps 11342 Jps 10804 DataNode 11110 SecondaryNameNode 10558 NameNode

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If you kept default configurations when running hadoop the port for the namenode would be 50070  You will need to find any processes running on this port and kill them first    Stop all running hadoop with   bin stop-all sh  check all processes running in port 50070 sudo netstat -tulpn   grep  50070   check any processes running in port    50070  if there are any the   will appear    at the RHS of the output  sudo kill -9  lt process id gt   kill the process  sudo rm -r  app hadoop tmp  delete the temp folder sudo mkdir  app hadoop tmp  recreate it sudo chmod 777    R  app hadoop tmp  777 is given for this example    purpose only  bin hadoop namenode    format  format hadoop namenode bin start-all sh  start-all hadoop services   Refer this blog

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Why do most answers here assume that all data needs to be deleted  reformatted  and then restart Hadoop  How do we know namenode is not progressing  but taking lots of time  It will do this when there is a large amount of data in HDFS  Check progress in logs before assuming anything is hung or stuck      kadmin hadoop-node-0 logs   tail hadoop-kadmin-namenode-hadoop-node-0 log      016-05-13 18 16 44 405 INFO org apache hadoop hdfs server namenode FSEditLogLoader  replaying edit log  117 141 transactions completed   83   2016-05-13 18 16 56 968 INFO org apache hadoop hdfs server namenode FSEditLogLoader  replaying edit log  121 141 transactions completed   86   2016-05-13 18 17 06 122 INFO org apache hadoop hdfs server namenode FSEditLogLoader  replaying edit log  122 141 transactions completed   87   2016-05-13 18 17 38 321 INFO org apache hadoop hdfs server namenode FSEditLogLoader  replaying edit log  123 141 transactions completed   87   2016-05-13 18 17 56 562 INFO org apache hadoop hdfs server namenode FSEditLogLoader  replaying edit log  124 141 transactions completed   88   2016-05-13 18 17 57 690 INFO org apache hadoop hdfs server namenode FSEditLogLoader  replaying edit log  127 141 transactions completed   90     This was after nearly an hour of waiting on a particular system  It is still progressing each time I look at it  Have patience with Hadoop when bringing up the system and check logs before assuming something is hung or not progressing

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Faced the same problem    1  Always check for the typing mistakes in the configuring the  xml files  especially the xml tags    2  go to bin dir  and type   start-all sh   3  then type jps   to check if processes are working

[hadoop] Namenode not getting started

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