question Re: Hadoop namenode never start in Archives of Support Questions (Read Only)

Hadoop namenode never start

yebinianhi — Fri, 22 Sep 2017 23:53:38 GMT

Hi, i manually installed hadoop 2.7.4

However, namenode never start.

i can see datanode and secondrynamenode are starting.

the core_site.xml

<property>
  <name>hadoop.tmp.dir</name>
  <value>/home/hduser/tmp</value>
  <description>A base for other temporary directories.</description>
 </property>
 <property>
  <name>fs.default.name</name>
  <value>hdfs://evotion00:54310</value>
 </property>

the hdfs_site.xml

<property>
  <name>dfs.replication</name>
  <value>3</value>
  <description>Default block replication.
  The actual number of replications can be specified when the file is created.
  The default is used if replication is not specified in create time.
  </description>
 </property>
 <property>
   <name>dfs.name.dir</name>
   <value>file:/home/hduser/hadoop_store/hdfs/namenode</value>
 </property>
 <property>
   <name>dfs.data.dir</name>
   <value>file:/home/hduser/hadoop_store/hdfs/datanode</value>
 </property>

I tried, hadoop namenode -format and restart but not working.

Many thanks in advance.

Re: Hadoop namenode never start

ajay_kumar — Sat, 23 Sep 2017 03:04:22 GMT

Hi @Bin Ye, Check NameNode logs and share any error/exception. Some common issues:

hostname specified in "fs.default.name" is valid. Also check if that port is not used by existing service.
Proper file permission for dirs specified in "dfs.name.dir" and "dfs.data.dir"

Re: Hadoop namenode never start

yebinianhi — Sat, 23 Sep 2017 03:32:11 GMT

Hi, @Ajay

When i format the namenode, it print out:

17/09/22 21:54:03 ERROR namenode.NameNode: Failed to start namenode.
java.io.IOException: Cannot create directory /hadoop/hdfs/namenode/current

In fact the hdfs_site.xml file is configred to store data in file:/home/hduser/hadoop_store/hdfs/namenode.

I don't understand how could this happen. This is a completely different location

Do you any reasons, why is this happening?

Many Thanks in advance.

Bin Ye

Re: Hadoop namenode never start

ajay_kumar — Tue, 26 Sep 2017 05:57:43 GMT

Hi @Bin Ye

Check for entry of "dfs.namenode.name.dir" in config files. Try to grep /hadoop/hdfs/namenode/current in config dir and see if you can locate the config file which is over-riding your settings.

Re: Hadoop namenode never start

1qaz5222 — Tue, 26 Sep 2017 09:30:07 GMT

Hi @Bin Ye

You should change this property to fit your setting

    <property>
      <name>dfs.namenode.name.dir</name>
      <value>/hadoop/hdfs/namenode</value>
    </property>

Re: Hadoop namenode never start

yebinianhi — Wed, 27 Sep 2017 19:40:51 GMT

Many thanks, for your reply. I found the errors. I have two versions of hadoop installed and the config folder is symlink to other place.