localhost: ERROR: Cannot set priority of datanode process 32156

Question

I am trying to install hadoop on ubuntu 16.04 but while starting the hadoop it will give me following error

localhost: ERROR: Cannot set priority of datanode process 32156.
Starting secondary namenodes [it-OptiPlex-3020]
2017-09-18 21:13:48,343 WARN util.NativeCodeLoader: Unable to load native-hadoop library for your platform... using builtin-java classes where applicable
Starting resourcemanager
Starting nodemanagers

Please someone tell me why i am getting this error ? Thanks in advance.

Answer 1

I have run into the same error when installing Hadoop 3.0.0-RC0. My situation was all services starting successfully except Datanode.

I found that some configs in hadoop-env.sh weren't correct in version 3.0.0-RC0, but were correct in version 2.x.

I ended up replacing my hadoop-env.sh with the official one and set JAVA_HOME and HADOOP_HOME. Now, Datanodes is working fine.

Answer 2

I suggest you take a look at your hadoop datanode logs. This is probably a configuration issue.

In my case, folders configured in dfs.datanode.data.dir didn't exist and an exception was thrown and written to log.

Answer 3

I had to deal with the same issue and kept getting the following exception:

Starting namenodes on [localhost]
Starting datanodes
localhost: ERROR: Cannot set priority of datanode process 8944
Starting secondary namenodes [MBPRO-0100.local]
2019-07-22 09:56:53,020 WARN util.NativeCodeLoader: Unable to load native-hadoop library for your platform... using builtin-java classes where applicable

As others have mentioned, you need to first make sure that all path parameters are set correctly which is what I checked first. Then followed these steps to solve the issue:

1- Stop dfs service and format hdfs:

sbin/stop-dfs.sh
sudo bin/hdfs namenode -format

2- Change permissions for the hadoop temp directory:

sudo chmod -R 777 /usr/local/Cellar/hadoop/hdfs/tmp

3- Start service again:

sbin/start-dfs.sh

Good luck

Answer 4

Faced the same issue, flushed the folders: datanode & namenode. I have put the folders in /hadoop_store/hdfs/namenode & /hadoop_store/hdfs/datanode

Post deleting the folders, recreate and then run the command hdfs namenode -format

Start the hadoop:

After the fix the logs look good:

Starting namenodes on [localhost]
Starting datanodes
Starting secondary namenodes [ip]
2019-02-11 09:41:30,426 WARN util.NativeCodeLoader: Unable to load native-hadoop library for your platform... using builtin-java classes where applicable

jps:

21857 NodeManager
21697 ResourceManager
21026 NameNode
22326 Jps
21207 DataNode
21435 SecondaryNameNode