Hello I am new to kafka and zookeeper concept. I have installed kafka and zookeeper in root and started as root user as nohup. The jps command gives output as:
root#rachita-Aspire-V7-481P:/usr/share/zookeeper/bin# jps
4037 Elasticsearch
1689 QuorumPeerMain
9899 Kafka
1692 Jps
3469 QuorumPeerMain
But when I try jps for rachita user the output is:
rachita#rachita-Aspire-V7-481P:/usr/share/zookeeper/bin$ jps
3261 Jps
Do I need to start kafka for every user on my machine who wish to use it?
Please give me any suggestions.
Also Haddop is installed as a separate user called hduser inside a group called hadoop. So can any user start all hadoop daemons or only hduser can do it.
Please help me with this. I am getting confused.
No, we don't need to start it for each user. Service should be started once by kafka-server-start on each node, which configured for kafka broker. If you are running kafka-server-start several times on a single node, you will start multiple brokers in it. Your user just does not have permissions to maintain the service, that is why you don't see it.
Best practice is to create a separate user as a member of hadoop group for each hadoop deamon and start it under this user account.
Related
I have Hadoop-3.1.3 and I can upload a file in hadoop pseudo distributed mode, also can display the contents of file.
but when I call jps command i am getting the following output
10912 DataNode
13072 ResourceManager
4480 NodeManager
6584 Jps
664 Namenode
I am unable to find secondary name node, is there a problem with any configuration or hadoop installation?
You're assuming that secondary namenode is started with psuedo-distributed?
If the basic commands work, then its fine.
You need to look at log files to know if something is broken, before asking elsewhere....
In general, I always suggest you use Apache Ambari to provision a Hadoop cluster
You can start the Secondary NameNode manually and observe the start up logs to see if there's anything wrong:
hdfs secondarynamenode
If there's no error, run jps again and hopefully you see SecondaryNameNode listed.
I'd suggest running hdfs --help and checking out all of the options, there's a lot of good stuff there.
I am trying to set of a multi-node hadoop cluster using Hadoop 3.0.0. There is no straightforward documentation on this so I had to read a lot of blogs. I am at a point where when I run start-all.sh I see daemon processes appearing in the name node as well as data nodes. However, when I go to http://namenode:9870 I see 0 live nodes.
To be more specific when I run start-all.sh I see
and I when I run jps I see NameNode, SecondaryNameNode and ResourceManager processes are running. On data nodes running jps shows DataNode and NodeManager are running.
What I get on the url is
Any guidance is greatly appreciated.
Thanks
17223 JobTracker
16897 DataNode
17518 Jps
17451 TaskTracker
17129 SecondaryNameNode
8571 FsShell
Name node is not displaying
Seems like you are using the same user for starting all users, so If namenode is coming in the jps output, Probably namenode daemons might be got killed to not started properly. you may use the following command for ensuring namenode process running or not
ps aux | grep -i namenode
If not running you may need to format your namenode before starting hdfs service, stop all hdfs deamons using stop-dfs.sh script then format your namenode using the below command and start HDFS using the start-dfs.sh script.
hadoop namenode -format
Go through the below SO post if you are hitting the below situation.
Hadoop namenode needs to be formatted after every computer start
If you are looking to check all running JVMs on the host via 'jps',
you need to run the command as root. Otherwise, 'jps' will only show
JVMs running as your currently logged-in user.
Please see this link for more:
https://groups.google.com/a/cloudera.org/forum/#!topic/cdh-user/1dlxmB_GVuU
Should always check the logs.. :)
I would like to see if the hdfs file system for Hadoop is working properly. I know that jps lists the daemons that are running, but I don't actually know which daemons to look for.
I ran the following commands:
$HADOOP_PREFIX/sbin/hadoop-daemon.sh start namenode
$HADOOP_PREFIX/sbin/hadoop-daemon.sh start datanode
$HADOOP_PREFIX/sbin/yarn-daemon.sh start resourcemanager
$HADOOP_PREFIX/sbin/yarn-daemon.sh start nodemanager
Only namenode, resourcemanager, and nodemanager appeared when I entered jps.
Which daemons are supposed to be running in order for hdfs/Hadoop to function? Also, what could you do to fix hdfs if it is not running?
Use any of the following approaches for to check your deamons status
JPS command would list all active deamons
the below is the most appropriate
hadoop dfsadmin -report
This would list down details of datanodes which is basically in a sense your HDFS
cat any file available in hdfs path.
So, I spent two weeks validating my setup (it was fine) , finally found this command:
sudo -u hdfs jps
Initially my simple JPS command was showing only one process, but Hadoop 2.6 under Ubuntu LTS 14.04 was up. I was using 'Sudo' to run the startup scripts.
Here is the startup that work with JPS listing multiple processes:
sudo su hduser
/usr/local/hadoop/sbin/start-dfs.sh
/usr/local/hadoop/sbin/start-yarn.sh
I have installed CDH3U5 on a 2 node cluster. Everything seems to run fine such as all the services, web UI, MR jobs, HDFS shell commands. However, interestingly, when I started the datanode service, it gave me an OK message that datanode is running as process say X. But when I run JPS, I do not see the label "Datanode" for the process. So the output looks like -
17153 TaskTracker
18908 Jps
16267
The process ID - 16267 is the Datanode process. All other checkpoints have passed. So this seems weird. The same thing happens on the other node in the cluster. Any insight into this behavior and if this is something that needs fixing would be helpful.
can you check the following and reply?
- web interface for namenode and what does it show there for livenode
- logfiles for datanode to see if any exception
- if datanode is pingable/ssh from namenode and viceversa
If all the above look ok I'm not sure what the problem is but to fix you can
- stop all hadoop deamons
- delete temp directory pointed in conf/core-site.xml for both NN and DN
- format namenode
- start deamon