I installed hadoop quite a while ago but I somehow have forgotten if I installed in pseudo distributed mode or not.How can I check it? while my hadoop is running
To know if you are running hadoop in Standalone or Pseudo distributed mode, verify your configuration files. Below information might help.
The tool jps lists out all running Java processes. From the console you can run
$ jps
and check whether JobTracker, TaskTracker and the HDFS daemons are running.
Check your configuration files:-
Go to directory where hadoop configurations are kept (/etc/hadoop in case of Ubuntu)
Look at slaves and masters files, if both have only localhost or (local IP) it is pseudo-distributed. In case slaves file is empty it is standalone.
Related
how can i differentiate hadoop standalone mode & pseudo distributed mode? Can anyone explain difference between all hadoop daemons as a single java process and separate java process
Hadoop standalone mode is running Hadoop commands without starting Hadoop daemons i.e. on local file system.
The pseudo distributed mode is running Hadoop daemons on a single machine.
I am new to the spark, After installing the spark using parcels available in the cloudera manager.
I have configured the files as shown in the below link from cloudera enterprise:
http://www.cloudera.com/content/cloudera-content/cloudera-docs/CM4Ent/4.8.1/Cloudera-Manager-Installation-Guide/cmig_spark_installation_standalone.html
After this setup, I have started all the nodes in the spark by running /opt/cloudera/parcels/SPARK/lib/spark/sbin/start-all.sh. But I couldn't run the worker nodes as I got the specified error below.
[root#localhost sbin]# sh start-all.sh
org.apache.spark.deploy.master.Master running as process 32405. Stop it first.
root#localhost.localdomain's password:
localhost.localdomain: starting org.apache.spark.deploy.worker.Worker, logging to /var/log/spark/spark-root-org.apache.spark.deploy.worker.Worker-1-localhost.localdomain.out
localhost.localdomain: failed to launch org.apache.spark.deploy.worker.Worker:
localhost.localdomain: at java.lang.ClassLoader.loadClass(libgcj.so.10)
localhost.localdomain: at gnu.java.lang.MainThread.run(libgcj.so.10)
localhost.localdomain: full log in /var/log/spark/spark-root-org.apache.spark.deploy.worker.Worker-1-localhost.localdomain.out
localhost.localdomain:starting org.apac
When I run jps command, I got:
23367 Jps
28053 QuorumPeerMain
28218 SecondaryNameNode
32405 Master
28148 DataNode
7852 Main
28159 NameNode
I couldn't run the worker node properly. Actually I thought to install a standalone spark where the master and worker work on a single machine. In slaves file of spark directory, I given the address as "localhost.localdomin" which is my host name. I am not aware of this settings file. Please any one cloud help me out with this installation process. Actually I couldn't run the worker nodes. But I can start the master node.
Thanks & Regards,
bips
Please notice error info below:
localhost.localdomain: at java.lang.ClassLoader.loadClass(libgcj.so.10)
I met the same error when I installed and started Spark master/workers on CentOS 6.2 x86_64 after making sure that libgcj.x86_64 and libgcj.i686 had been installed on my server, finally I solved it. Below is my solution, wish it can help you.
It seem as if your JAVA_HOME environment parameter didn't set correctly.
Maybe, your JAVA_HOME links to system embedded java, e.g. java version "1.5.0".
Spark needs java version >= 1.6.0. If you are using java 1.5.0 to start Spark, you will see this error info.
Try to export JAVA_HOME="your java home path", then start Spark again.
I installed the hadoop 2.2 system on my ubuntu box using this tutorial
http://codesfusion.blogspot.com/2013/11/hadoop-2x-core-hdfs-and-yarn-components.html
Everything worked fine for me and now when I do
http://localhost:50070
I can see the management UI for HDFS. Very good!!
But the I am going through another tutorial which tells me that there must be a task manager UI running at http://mymachine.com:50030 and http://mymachine.com:50060
on my machine I cannot open these ports.
I have already done
start-dfs.sh
start-yarn.sh
start-all.sh
is something wrong? why can't I see the task manager UI?
You have installed YARN (MRv2) which runs the ResourceManager. The URL http://mymachine.com:50030 is the web address for the JobTracker daemon that comes with MRv1 and hence you are not able to see it.
To see the ResourceManager UI, check your yarn-site.xml file for the following property:
yarn.resourcemanager.webapp.address
By default, it should point to : resource_manager_hostname:8088
Assuming your ResourceManager runs on mymachine, you should see the ResourceManager UI at http://mymachine.com:8088/
Make sure all your deamons are up and running before you visit the URL for the ResourceManager.
For Hadoop 2[aka YARN/MRV2] - Any hadoop installation version-ed 2.x or higher its at port number 8088. eg. localhost:8088
For Hadoop 1 - Any hadoop installation version-ed lower than 2.x[eg 1.x or 0.x] its at port number 50030. eg localhost:50030
By default HadoopUI location is as below
http://mymachine.com:50070
I am a student, interested in Hadoop and started to explore it recently.
I tried adding an additional DataNode in the pseudo-distributed mode but failed.
I am following the Yahoo developer tutorial and so the version of Hadoop I am using is hadoop-0.18.0
I tried to start up using 2 methods I found online:
Method 1 (link)
I have a problem with this line
bin/hadoop-daemon.sh --script bin/hdfs $1 datanode $DN_CONF_OPTS
--script bin/hdfs doesn't seem to be valid in the version I am using. I changed it to --config $HADOOP_HOME/conf2 with all the configuration files in that directory, but when the script is ran it gave the error:
Usage: Java DataNode [-rollback]
Any idea what does the error mean? The log files are created but DataNode did not start.
Method 2 (link)
Basically I duplicated conf folder to conf2 folder, making necessary changes documented on the website to hadoop-site.xml and hadoop-env.sh. then I ran the command
./hadoop-daemon.sh --config ..../conf2 start datanode
it gives the error:
datanode running as process 4190. stop it first.
So I guess this is the 1st DataNode that was started, and the command failed to start another DataNode.
Is there anything I can do to start additional DataNode in the Yahoo VM Hadoop environment? Any help/advice would be greatly appreciated.
Hadoop start/stop scripts use /tmp as a default directory for storing PIDs of already started daemons. In your situation, when you start second datanode, startup script finds /tmp/hadoop-someuser-datanode.pid file from the first datanode and assumes that the datanode daemon is already started.
The plain solution is to set HADOOP_PID_DIR env variable to something else (but not /tmp). Also do not forget to update all network port numbers in conf2.
The smart solution is start a second VM with hadoop environment and join them in a single cluster. It's the way hadoop is intended to use.
I've configured hadoop 1.0.4 in pseudo-distributed mode. Everything's good, I can put local files in HDFS and run wordcount task. But I just can't access the jobtracker web UI through localhost:50030, localhost:50070 doesn't work neither.
HTTP ERROR 404
Problem accessing /jobtracker.jsp. Reason:
/jobtracker.jsp Powered by Jetty://
I look at the log files, but there's no error...
I used to have some problem with datanode, and jobtracker complained about replication, but that is solved and now all daemons are good (namenode, datanode, jobtracker, tasktracker, secondarynamenode) and no error in any of the log files.
Any suggestions?
Ok finally I solved it myself, I had to re-install the system then re-install hadoop. I think the problem should be that I've previously installed the CDH4 on my system, which is hadoop 2.0.0 and even if I uninstalled all of its packages (debian system) and change the tmp folder of HDFS, but maybe there's still something left. The only way is to restart over.