I am trying to use webhdfs.
I have place these lines to hdfs-site.xml file:
<property>
<name>dfs.webhdfs.enabled</name>
<value>true</value>
</property>
I did a stop-all.sh and start-all.sh on hadoop cluster.
I am trying to see if I can use webhdfs by this url call:
http://<myserver>:50070/webhdfs/v1/user/root/output/?op=LISTSTATUS
if I just do:
http://<myserver>:50070
I get hadoop over view page.
So, I can remotely access my server at port 50070 but webhdfs piece does not seem to be working. I would like to be able to access hdfs using rest api calls, to either read or put files.
any ideas what I am missing here?
Related
My core-site.xml is configured like this.
<configuration>
<property>
<name>fs.default.name</name>
<value>hdfs://localhost:9000</value>
</property>
</configuration>
Now, when I enter 'start-all.cmd' in the command prompt, I see the services startup and I enter this 'localhost:9000' into my web browser, and I get an error message. When I enter this 'localhost:8088' into the web browser, I see the Hadoop cluster, which is up and running just fine. It seems like the core-site.xml is ignored, and the 'localhost:8088' is picked up from somewhere else, but I can't find it. Can someone give me a quick and dirty description of how this actually works? I already Googled for an answer, but I didn't seen anything useful about this.
format name node using this :
hdfs namenode -format
For more information:
Follow installation steps from this Site. It is working perfectly fine.
http://pingax.com/install-hadoop2-6-0-on-ubuntu/
I have a hadoop cluster on aws and I am trying to access it from outside the cluster through a hadoop client. I can successfully hdfs dfs -ls and see all contents but when I try to put or get a file I get this error:
Exception in thread "main" java.lang.NullPointerException
at org.apache.hadoop.fs.FsShell.displayError(FsShell.java:304)
at org.apache.hadoop.fs.FsShell.run(FsShell.java:289)
at org.apache.hadoop.util.ToolRunner.run(ToolRunner.java:70)
at org.apache.hadoop.util.ToolRunner.run(ToolRunner.java:84)
at org.apache.hadoop.fs.FsShell.main(FsShell.java:340)
I have hadoop 2.6.0 installed in both my cluster and my local machine. I have copied the conf files of the cluster to the local machine and have these options in hdfs-site.xml (along with some other options).
<property>
<name>dfs.client.use.datanode.hostname</name>
<value>true</value>
</property>
<property>
<name>dfs.permissions.enable</name>
<value>false</value>
</property>
My core-site.xml contains a single property in both the cluster and the client:
<property>
<name>fs.defaultFS</name>
<value>hdfs://public-dns:9000</value>
<description>NameNode URI</description>
</property>
I found similar questions but wasn't able to find a solution to this.
How about you SSH into that machine?
I know this is a very bad idea but to get the work done, you can first copy that file on machine using scp and then SSH into that cluster/master and do hdfs dfs -put on that copied local file.
You can also automate this via a script but again, this is just to get the work done for now.
Wait for someone else to answer to know the proper way!
I had similar issue with my cluster when running hadoop fs -get and I could resolve it. Just check if all your data nodes are resolvable using FQDN(Fully Qualified Domain Name) from your local host. In my case nc command was successful using ip addresses for data nodes but not with host name.
run below command :
for i in cat /<host list file>; do nc -vz $i 50010; done
50010 is default datanode port
when you run any hadoop command it try to connect to data nodes using FQDN and thats where it gives this weird NPE.
Do below export and run your hadoop command
export HADOOP_ROOT_LOGGER=DEBUG,console
you will see this NPE comes when it is trying to connect to any datanode for data transfer.
I had a java code which was also doing hadoop fs -get using APIs and there ,exception was more clearer
java.lang.Exception: java.nio.channels.UnresolvedAddressException
Let me know if this helps you.
I have an old Hadoop install that I'm looking to update to Hadoop 2. In the
old setup, I have a $HADOOP_HOME/conf/masters file that specifies the
secondary namenode.
Looking through the Hadoop 2 documentation I can't find any mention of a
"masters" file, or how to setup a secondary namenode.
Any help in the right direction would be appreciated.
The slaves and masters files in the conf folder are only used by some scripts in the bin folder like start-mapred.sh, start-dfs.sh and start-all.sh scripts.
These scripts are a mere convenience so that you can run them from a single node to ssh into each master / slave node and start the desired hadoop service daemons.
You only need these files on the name node machine if you intend to launch your cluster from this single node (using password-less ssh).
Alternatively, You can also start an Hadoop daemon manually on a machine via
bin/hadoop-daemon.sh start [namenode | secondarynamenode | datanode | jobtracker | tasktracker]
In order to run the secondary name node, use the above script on the designated machines providing the 'secondarynamenode' value to the script
See #pwnz0r 's 2nd comment on answer on How separate hadoop secondary namenode from primary namenode?
To reiterate here:
In hdfs-site.xml:
<property>
<name>dfs.secondary.http.address</name>
<value>$secondarynamenode.full.hostname:50090</value>
<description>SecondaryNameNodeHostname</description>
</property>
I am using Hadoop 2.6 and had to use
<property>
<name>dfs.secondary.http.address</name>
<value>secondarynamenode.hostname:50090</value>
</property>
for further details refer https://hadoop.apache.org/docs/r2.6.0/hadoop-project-dist/hadoop-hdfs/hdfs-default.xml
Update hdfs-site.xml file by updating and adding following property
cd $HADOOP_HOME/etc/hadoop
sudo vi hdfs-site.xml
Then paste these lines into configuration tag
<property>
<name>dfs.secondary.http.address</name>
<value>hostname:50090</value>
</property>
I've been struggling with getting Hadoop and Map/Reduce to start using a separate temporary directory instead of the /tmp on my root directory.
I've added the following to my core-site.xml config file:
<property>
<name>hadoop.tmp.dir</name>
<value>/data/tmp</value>
</property>
I've added the following to my mapreduce-site.xml config file:
<property>
<name>mapreduce.cluster.local.dir</name>
<value>${hadoop.tmp.dir}/mapred/local</value>
</property>
<property>
<name>mapreduce.jobtracker.system.dir</name>
<value>${hadoop.tmp.dir}/mapred/system</value>
</property>
<property>
<name>mapreduce.jobtracker.staging.root.dir</name>
<value>${hadoop.tmp.dir}/mapred/staging</value>
</property>
<property>
<name>mapreduce.cluster.temp.dir</name>
<value>${hadoop.tmp.dir}/mapred/temp</value>
</property>
No matter what job I run though, it's still doing all of the intermediate work out in the /tmp directory. I've been watching it do it via df -h and when I go in there, there are all of the temporary files it creates.
Am I missing something from the config?
This is on a 10 node Linux CentOS cluster running 2.1.0.2.0.6.0 of Hadoop/Yarn Mapreduce.
EDIT:
After some further research, the settings seem to be working on my management and namednode/secondarynamed nodes boxes. It is only on the data nodes that this is not working and it is only with the mapreduce temporary output files that are still going to /tmp on my root drive, not the my data mount where I have set in the configuration files.
If you are running Hadoop 2.0, then the proper name of the config file you need to change is mapred-site.xml, not mapreduce-site.xml.
An example can be found on the Apache site: http://hadoop.apache.org/docs/r2.3.0/hadoop-mapreduce-client/hadoop-mapreduce-client-core/mapred-default.xml
and it uses the mapreduce.cluster.local.dir property name, with a default value of ${hadoop.tmp.dir}/mapred/local
Try renaming your mapreduce-site.xml file to mapred-site.xml in your /etc/hadoop/conf/ directories and see if that fixes it.
If you are using Ambari, you should be able to just go to use the "Add Property" button on the MapReduce2 / Custom mapred-site.xml section, enter 'mapreduce.cluster.local.dir' for the property name, and a comma separated list of directories you want to use.
I think you need to specify this property in hdfs-site.xml rather than core-site.xml.Try setting this property in hdfs-site.xml. I hope this will solve your problem
The mapreduce properties should be in mapred-site.xml.
I was facing a similar issue where some nodes would not honor the hadoop.tmp.dir set in the config.
A reboot of the misbehaving nodes fixed it for me.
I have installed Hadoop in pseudo distributed mode on my laptop, OS is Ubuntu.
I have changed paths where hadoop will store its data (by default hadoop stores data in /tmp folder)
hdfs-site.xml file looks as below :
<property>
<name>dfs.data.dir</name>
<value>/HADOOP_CLUSTER_DATA/data</value>
</property>
Now whenever I restart machine and try to start hadoop cluster using start-all.sh script, data node never starts. I confirmed that data node is not start by checking logs and by using jps command.
Then I
Stopped cluster using stop-all.sh script.
Formatted HDFS using hadoop namenode -format command.
Started cluster using start-all.sh script.
Now everything works fine even if I stop and start cluster again. Problem occurs only when I restart machine and try to start the cluster.
Has anyone encountered similar problem?
Why this is happening and
How can we solve this problem?
By changing dfs.datanode.data.dir away from /tmp you indeed made the data (the blocks) survive across a reboot. However there is more to HDFS than just blocks. You need to make sure all the relevant dirs point away from /tmp, most notably dfs.namenode.name.dir (I can't tell what other dirs you have to change, it depends on your config, but the namenode dir is mandatory, could be also sufficient).
I would also recommend using a more recent Hadoop distribution. BTW, the 1.1 namenode dir setting is dfs.name.dir.
For those who use hadoop 2.0 or above versions config file names may be different.
As this answer points out, go to the /etc/hadoop directory of your hadoop installation.
Open the file hdfs-site.xml. This user configuration will override the default hadoop configurations, that are loaded by the java classloader before.
Add dfs.namenode.name.dir property and set a new namenode dir (default is file://${hadoop.tmp.dir}/dfs/name).
Do the same for dfs.datanode.data.dir property (default is file://${hadoop.tmp.dir}/dfs/data).
For example:
<property>
<name>dfs.namenode.name.dir</name>
<value>/Users/samuel/Documents/hadoop_data/name</value>
</property>
<property>
<name>dfs.datanode.data.dir</name>
<value>/Users/samuel/Documents/hadoop_data/data</value>
</property>
Other property where a tmp dir appears is dfs.namenode.checkpoint.dir. Its default value is: file://${hadoop.tmp.dir}/dfs/namesecondary.
If you want, you can easily also add this property:
<property>
<name>dfs.namenode.checkpoint.dir</name>
<value>/Users/samuel/Documents/hadoop_data/namesecondary</value>
</property>