I have a confusion with hadoop 2.7.
After I run the start-all.sh, I type the jps command, but I haven't find jobtracker and tasktracker in the list, why?
Thanks for any help!
In Hadoop-2.7.2, mapreduce framework changed to YARN. So you can find Resourcemanager and Nodemanager instead of jobtracker and tasktracker.
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unable to see Task tracker and Jobtracker after Hadoop single node installation 2.5.1
For technical information, check the below link
http://blog.cloudera.com/blog/2013/11/migrating-to-mapreduce-2-on-yarn-for-operators/
Related
I recently installed Hadoop 3.3.1 on Ubuntu (single node cluster) using this tutorial.
The start-dfs.sh and start-yarn.sh shows all the processing running properly.
However when I use the jps command, it returns only jps, with none of the other nodes, trackers showing.
I am new to Hadoop and lost on how to solve this. Any help is appreciated.
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
What I know is YARN is introduced and it replaced JobTracker and TaskTracker.
I have seen is some Hadoop 2.6.0/2.7.0 installation tutorials and they are configuring mapreduce.framework.name as yarn and mapred.job.tracker property as local or host:port.
The description for mapred.job.tracker property is
"The host and port that the MapReduce job tracker runs at. If "local",
then jobs are run in-process as a single map and reduce task."
My doubt is why are configuring it if we are using YARN , I mean JobTracker shouldn't be running right?
Forgive me if my question is dumb.
Edit: These are the tutorials I was talking about.
http://chaalpritam.blogspot.in/2015/01/hadoop-260-multi-node-cluster-setup-on.html
http://pingax.com/install-apache-hadoop-ubuntu-cluster-setup/
https://chawlasumit.wordpress.com/2015/03/09/install-a-multi-node-hadoop-cluster-on-ubuntu-14-04/
This is just a guess, but either those tutorials talking about configuring the JobTracker in YARN are written by people who don't know what YARN is, or they set it in case you decide to stop working with YARN someday. You are right: the JobTracker and TaskTracker do not exist in YARN. You can add the properties if you want, but they will be ignored. New properties for each of the components replacing the JobTracker and the TaskTracker were added with YARN, such as yarn.resourcemanager.address to replace mapred.jobtracker.address.
If you list your Java processes when running Hadoop under YARN, you see no JobTrackeror TaskTracker:
10561 Jps
20605 NameNode
17176 DataNode
18521 ResourceManager
19625 NodeManager
18424 JobHistoryServer
You can read more about how YARN works here.
Iam new to Hadoop 2.5.1. As i have already installed Hadoop 1.0.4 previously, i thought installation process would be same so followed following tutorial.
http://www.michael-noll.com/tutorials/running-hadoop-on-ubuntu-linux-single-node-cluster/
Every thing was fine, even i have given these settings in core-site.xml
<name>fs.default.name</name>
<value>hdfs://localhost:54310</value>
But i have seen in several sites this value as 9000.
And also changes in yarn.xml.
Still everything works fine when i run a mapreduce job. But my question is
when i run command jps it gives me this output..
hduser#secondmaster:~$ jps
5178 ResourceManager
5038 SecondaryNameNode
4863 DataNode
5301 NodeManager
4719 NameNode
6683 Jps
I dont see task tracker and job tracker in jps. Where are these demons running.
And without these deamons how am i able to run Mapreduce job.
Thanks,
Sreelatha K.
From hadoop version hadoop 2.0 onwards, default processing framework has been changed to YARN from Classic Mapreduce. You are using YARN, where you cannot see Jobtracker, Tasker in YARN. Jobtracker and Tasktracker is replaced by Resource manager and Nodemanager respectively in YARN.
But still you have an option to use Classic Mapreduce framework instead of YARN.
In Hadoop 2 there is an alternative method to run MapReduce jobs, called YARN. Since you have made changes in yarn.xml, MapReduce processing happens using YARN, not using the traditional MapReduce framework. That's probably be the reason why you don't see TaskTracker and JobTracker listed after executing the jps command. Note that ResourceManager and NodeManager are the daemons for YARN.
YARN is next generation of Resource Manager who can able to integrate with Apache spark, storm and many more tools you can use to write map-reduce jobs
I Installed Hadoop 2.4.X. As expected there is no JobTracker and TaskTracker. Its Yarn based. Is there any way to make it use old JobTracker and TaskTracker for MapReduce and not based on Yarn ? In short can I make JT and TT daemons running on this ?
By default there is no configuration file for map reduce in the 2.4.x installation even though there is a file called mapred-site.xml.template.Rename the file to mapred-site.xml and remember to set the property mapred.framework.name to classic to use the job tracker and tasktracker.Also the start scripts start-all.sh cannot be used as it executes the scripts start-dfs.sh and start-yarn.sh.You need to execute the script that starts jobtracker and tasktracker.
As described above, there is no Jobtracker and Tasktracer in Hadoop 2.0 (yarn). It's better to follow this instruction (http://codesfusion.blogspot.in/2013/10/setup-hadoop-2x-220-on-ubuntu.html) to get the idea, and you will find the processes are as:
25578 ResourceManager
25411 SecondaryNameNode
447 Jps
29464 NameNode
25222 DataNode
25905 NodeManager