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.
Related
I have just installed Cloudera VM setup for hadoop. But when I open the command prompt and want to start all daemons for hadoop using command 'start-all.sh' , I get an error stating "bash : start-all.sh: command not found".
I have tried 'start-dfs.sh' too yet still gives the same error. When I use 'jps' command, I can see that none of the daemons have been started.
You can find start-all.sh and start-dfs.sh scripts in bin or sbin folders. You can use the following command to find that. Go to hadoop installation folder and run this command.
find . -name 'start-all.sh' # Finds files having name similar to start-all.sh
Then you can specify the path to start all the daemons using bash /path/to/start-all.sh
If you're using the QuickStart VM then the right way to start the cluster (as #cricket_007 hinted) is by restarting it in the Cloudera Manager UI. The start-all.sh scripts will not work since those only apply to the Hadoop servers (Name Node, Data Node, Resource Manager, Node Manager ...) but not all the services in the ecosystem (like Hive, Impala, Spark, Oozie, Hue ...).
You can refer to the YouTube video and the official documentation Starting, Stopping, Refreshing, and Restarting a Cluster
It is my first time in installing Hadoop on my Linux (Fedora distro) running on VM (using Parallel on my Mac). And I followed every step on this video and including the textual version of it.And then when I run it on localhost (or the equivalent value from hostname) in port 50070, I got the following message.
...can't establish a connection to the server at localhost:50070
When I run the jps by the way command I don't have the datanode and namenode unlike at the end of the textual version tutorial which has the following:
While mine has only the following processes running:
6021 NodeManager
3947 SecondaryNameNode
5788 ResourceManager
8941 Jps
When I run the hadoop namenode command I have some of the following [redacted] error:
Cannot access storage directory /usr/local/hadoop_store/hdfs/namenode
16/10/11 21:52:45 WARN namenode.FSNamesystem: Encountered exception loading fsimage
org.apache.hadoop.hdfs.server.common.InconsistentFSStateException: Directory /usr/local/hadoop_store/hdfs/namenode is in an inconsistent state: storage directory does not exist or is not accessible.
I tried to access by the way the above mentioned directories and it existed.
Any hint for this newbie? ;-)
You would need to give read and write permission to user with which you are running the services on directory /usr/local/hadoop_store/hdfs/namenode.
Once done, you should run format command using hadoop namenode -format
Then try to start your services.
delete files /app/hadoop/tmp/*
and try again formatting the namenode and then start-dfs.sh & start-yarn.sh
Job tracker and Task tracker don't sow up when ran the start-all.sh command in ububtu for hadoop
I do get the rest of the processes while i run the "JPS" command in unix.
Not sure why i am not being shown with the job tracker and task tracker.Have been following couple of links and couldn't get my prob sorted.
Steps done :
-Multiple times formatted the namenode
-Multiple time deleted and recreated the tmp folder with appropriate permissions.
What could be the issue ?
Any suggestions would really help me as i am struggling in setting up hadoop on my laptop.I am new to it though.
Try starting jobtracker and tasktracker separately.
From your hadoop HOME directory run
. bin/../libexec/hadoop-config.sh
Then from hadoop BIN directory run
hadoop-daemon.sh --config $HADOOP_CONF_DIR start jobtracker
hadoop-daemon.sh --config $HADOOP_CONF_DIR start tasktracker
You must have been using hadoop 2.x version where jobtracker is replaced with YARN resource manager. Using jps(jdk is needed) you can check whether resouce manager is running. If it is running then the default url for it is (host-name):8088. You can check your nodes,jobs also configuration there.If not running then start them with sbin/start-yarn.sh.
I have started configuring Hadoop 2.1.0-beta version for single node. I followed steps mentioned in Michael Noll's Tutorial (http://www.michael-noll.com/tutorials/running-hadoop-on-ubuntu-linux-multi-node-cluster/#configuring-single-node-clusters-first). Every thing I did and configured well. As a result of JPS, I got that NameNode, DataNode, Secondary NameNode started fine. Then I found out that there is no start-mapred.sh script. So I tried starting the jobtracker using hadoop-daemons.sh (hadoop-daemon.sh --config /home/nayan/dev/hadoop/etc/hadoop/ start jobtracker) and it resulted in failure with message "Sorry, the jobtracker command is no longer supported. You may find similar functionality with the "yarn" shell command.". I do not know what all configuration changes (if any) I need to make. I made changes in "yarn-site.xml" file, as suggested in Hadoop:The Definitive Guide. But could not proceed further. Where can I find out about Yarn. I checked Apache site, but could not figure it out.
You need to check your configuration xml files. Sometimes if you have any problrm in xml then some daemons wont start.
and try to use ./start-all.sh and then JPS
you can use start-yarn.sh to start the ResourceManger and Jobtracker daemons
I usually start everything using these two commands
./start-dfs.sh
./start-yarn.sh
You Should use start-dfs.sh for Hdfs Daemons and start-yarn.sh for Resource manager and nodemanager daemon both are in /bin of hadoop.
./start-dfs.sh or start-dfs.sh will start only HDFS components , while ./start-yarn.sh or start-yarn.sh will start Yarn component like NodeManager , Resource manager etc. If you don't want to start both the components separately , try using this command :
./start-all.sh or start-all.sh (This is deprecated command though).
To answer your question , use ./start-yarn.sh
Cheers!
First have to start the yarn daemons in the YARN( HADOOP 2.x) Environment.
So start with this
at /hadoop_installed_path/sbin$ ./start-yarn.sh
Once the yarn daemons started then we can start df daemons
at /hadoop_installed_path/sbin$ ./start-dfs.sh
1.You should check all the steps in Hadoop The definitive guide.
if it's all proper than use start-all.sh
than run jps.
2.some time You have to close console for reflecting your changes.so close the console and reopen it again and then try jps,
hope this will help.
I set up and configured sudo node hadoop environment on ubuntu 12.04 LTS using following tutorial
http://www.michael-noll.com/tutorials/running-hadoop-on-ubuntu-linux-multi-node-cluster/#formatting-the-hdfs-filesystem-via-the-namenode
After typing hadoop/bin $ start-all.sh
everything going fine then i checked the Jps
then NameNode, JobTracker ,TaskTracker,SecondaryNode have been started but DataNode not started ...
If any know how to resolve this issue please let me know..
ya i resolved it...
java.io.IOException: Incompatible namespaceIDs
If you see the error java.io.IOException: Incompatible namespaceIDs in the logs of a DataNode (logs/hadoop-hduser-datanode-.log), chances are you are affected by issue HDFS-107 (formerly known as HADOOP-1212).
The full error looked like this on my machines:
... ERROR org.apache.hadoop.dfs.DataNode: java.io.IOException: Incompatible namespaceIDs in /app/hadoop/tmp/dfs/data: namenode namespaceID = 308967713; datanode namespaceID = 113030094
at org.apache.hadoop.dfs.DataStorage.doTransition(DataStorage.java:281)
at org.apache.hadoop.dfs.DataStorage.recoverTransitionRead(DataStorage.java:121)
at org.apache.hadoop.dfs.DataNode.startDataNode(DataNode.java:230)
at org.apache.hadoop.dfs.DataNode.(DataNode.java:199)
at org.apache.hadoop.dfs.DataNode.makeInstance(DataNode.java:1202)
at org.apache.hadoop.dfs.DataNode.run(DataNode.java:1146)
at org.apache.hadoop.dfs.DataNode.createDataNode(DataNode.java:1167)
at org.apache.hadoop.dfs.DataNode.main(DataNode.java:1326)
t the moment, there seem to be two workarounds as described below.
Workaround 1: Start from scratch
I can testify that the following steps solve this error, but the side effects won’t make you happy (me neither). The crude workaround I have found is to:
Stop the cluster
Delete the data directory on the problematic DataNode: the directory is specified by dfs.data.dir in conf/hdfs-site.xml; if you followed this tutorial, the relevant directory is /app/hadoop/tmp/dfs/data
Reformat the NameNode (NOTE: all HDFS data is lost during this process!)
Restart the cluster
When deleting all the HDFS data and starting from scratch does not sound like a good idea (it might be ok during the initial setup/testing), you might give the second approach a try.
Workaround 2: Updating namespaceID of problematic DataNodes
Big thanks to Jared Stehler for the following suggestion. I have not tested it myself yet, but feel free to try it out and send me your feedback. This workaround is “minimally invasive” as you only have to edit one file on the problematic DataNodes:
Stop the DataNode
Edit the value of namespaceID in /current/VERSION to match the value of the current NameNode
Restart the DataNode
If you followed the instructions in my tutorials, the full path of the relevant files are:
NameNode: /app/hadoop/tmp/dfs/name/current/VERSION
DataNode: /app/hadoop/tmp/dfs/data/current/VERSION (background: dfs.data.dir is by default set to ${hadoop.tmp.dir}/dfs/data, and we set hadoop.tmp.dir in this tutorial to /app/hadoop/tmp).
The solution for the problem is clearly given in the following site:
http://www.michael-noll.com/tutorials/running-hadoop-on-ubuntu-linux-multi-node-cluster/#java-io-ioexception-incompatible-namespaceids