I have a Hadoop cluster running on another server. I am able to ssh into that server and use Hive to run queries. I'm trying to determine if I can query that server remotely, using Hive or Beeline; would prefer Beeline, since it's not being deprecated.
I used Homebrew to install Hadoop and Hive. However it complains about missing environment variables and path. But it seems like those things are set, so I must not have configured it correctly. So, what are the steps I need to go through to execute queries on a remote Hadoop from my Mac? Do I have to go through all the steps to set up a local Hadoop instance just so I can query a remote Hadoop?
~ (master) 10:24:30
# next line is from the docs
$ beeline -u jdbc:hive2://localhost:10000/default -n scott -w password_file
Cannot find hadoop installation: $HADOOP_HOME or $HADOOP_PREFIX must be set or hadoop must be in the path
~ (master) 10:25:05
$ which hadoop
/usr/local/bin/hadoop
~ (master) 10:25:18
$ echo $HADOOP_HOME
/usr/local/Cellar/hadoop/2.7.3/bin
Related
If i install hadoop using 'hadoop' user, and install hive using 'hive' user on same node(Pseudo distribution mode).
How can my hive access hadoop?
when i input 'hive --version', i receive error like this:
Cannot find hadoop installation: $HADOOP_HOME or $HADOOP_PREFIX must be set or hadoop must be in the path.
The question is hive user have no right to access hadoop, but i don't know how to fix it.
Thanks a lot.
As the error says, $HADOOP_HOME or $HADOOP_PREFIX must be set or hadoop must be in the path.
So, edit /home/hive/.bash_profile, for example assuming you're on Linux, and add one of those values to set the environment variable to the downloaded Hadoop package
For example
export HADOOP_HOME=/opt/hadoop # example
export PATH=$HADOOP_HOME/bin:$PATH
I am using CDH 5.3.2 cluster and have a requirement to be able to start/stop impala daemons from a script. The command mentioned in Cloudera Docs
sudo service impala-server start
works fine on my CDH 5.10 local VM but on CDH 5.3.2 cluster I get an error "impala-server: unrecognized service". On checking in /etc/init.d I see that no such service is listed either (while its listed in 5.10 version)
Then i tried to restart the service directly from impala bin directory
cd /usr/bin
./impalad stop
However running into below error now:
E0918 11:55:27.815739 12046 JniFrontend.java:622] FileSystem is file:///
W0918 11:55:27.817589 12046 JniFrontend.java:534] Cannot detect CDH version. Skipping Hadoop configuration checks
E0918 11:55:27.817620 12046 impala-server.cc:210] Unsupported file system. Impala only supports DistributedFileSystem but the configured filesystem is: LocalFileSystem.fs.defaultFS(file:///) might be set incorrectly
E0918 11:55:27.817631 12046 impala-server.cc:212] Aborting Impala Server startup due to improper configuration
I checked core-site.xml on Cloudera Manager and fs.defaultFS is correctly set so not sure where its picking the value from. Any pointers on how to go further on this?
The init.d service packages to start Impala from the command line are meant to be used for CDH users who do NOT want to use Cloudera Manager. The right way to start and stop Impala on a Cloudera Manager cluster is to use the CM API:
https://cloudera.github.io/cm_api/apidocs/v17/index.html
start cluster service API
stop cluster service API
commands API
The tutorial shows how to use the CM APIs but for your situation you probably need to do:
$ curl -X POST -u USER:PASSWORD \
'CM_URL//api/v1/clusters/CLUSTERNAME/services/IMPALA_SERVICE/commands/stop'
replacing USER, PASSWORD, CM_URL, CLUSTERNAME, IMPALA_SERVICE_NAME with the appropriate values. The curl command will return a command ID.
Then poll this API with the command ID to see that the start/stop operation completed.
$ curl -u USER:PASSWORD 'CM_URL//api/v1/commands/COMMAND_ID'
However, if you still want to use the init.d service packages then you'll need to install the impala-server package.
My local machine does not have an hdfs installation. I want to retrieve files from a remote hdfs cluster. What's the best way to achieve this? Do I need to get the files from hdfs to one of the cluster machines fs and then use ssh to retrieve them? I want to be able to do this programmatically through say a bash script.
Here are the steps:
Make sure there is connectivity between your host and the target cluster
Configure your host as client, you need to install compatible hadoop binaries. Also your host needs to be running using same operating system.
Make sure you have the same configuration files (core-site.xml, hdfs-site.xml)
You can run hadoop fs -get command to get the files directly
Also there are alternatives
If Webhdfs/httpFS is configured, you can actually download files using curl or even your browser. You can write bash scritps if Webhdfs is configured.
If your host cannot have Hadoop binaries installed to be client, then you can use following instructions.
enable password less login from your host to the one of the node on the cluster
run command ssh <user>#<host> "hadoop fs -get <hdfs_path> <os_path>"
then scp command to copy files
You can have the above 2 commands in one script
We are setting up automated deployments on a headless system: so using the GUI is not an option here.
Where is start-dfs.sh script for hdfs in Hortonworks Data Platform? CDH / cloudera packages those files under the hadoop/sbin directory. However when we search for those scripts under HDP they are not found:
$ pwd
/usr/hdp/current
Which scripts exist in HDP ?
[stack#s1-639016 current]$ find -L . -name \*.sh
./hadoop-hdfs-client/sbin/refresh-namenodes.sh
./hadoop-hdfs-client/sbin/distribute-exclude.sh
./hadoop-hdfs-datanode/sbin/refresh-namenodes.sh
./hadoop-hdfs-datanode/sbin/distribute-exclude.sh
./hadoop-hdfs-nfs3/sbin/refresh-namenodes.sh
./hadoop-hdfs-nfs3/sbin/distribute-exclude.sh
./hadoop-hdfs-secondarynamenode/sbin/refresh-namenodes.sh
./hadoop-hdfs-secondarynamenode/sbin/distribute-exclude.sh
./hadoop-hdfs-namenode/sbin/refresh-namenodes.sh
./hadoop-hdfs-namenode/sbin/distribute-exclude.sh
./hadoop-hdfs-journalnode/sbin/refresh-namenodes.sh
./hadoop-hdfs-journalnode/sbin/distribute-exclude.sh
./hadoop-hdfs-portmap/sbin/refresh-namenodes.sh
./hadoop-hdfs-portmap/sbin/distribute-exclude.sh
./hadoop-client/sbin/hadoop-daemon.sh
./hadoop-client/sbin/slaves.sh
./hadoop-client/sbin/hadoop-daemons.sh
./hadoop-client/etc/hadoop/hadoop-env.sh
./hadoop-client/etc/hadoop/kms-env.sh
./hadoop-client/etc/hadoop/mapred-env.sh
./hadoop-client/conf/hadoop-env.sh
./hadoop-client/conf/kms-env.sh
./hadoop-client/conf/mapred-env.sh
./hadoop-client/libexec/kms-config.sh
./hadoop-client/libexec/init-hdfs.sh
./hadoop-client/libexec/hadoop-layout.sh
./hadoop-client/libexec/hadoop-config.sh
./hadoop-client/libexec/hdfs-config.sh
./zookeeper-client/conf/zookeeper-env.sh
./zookeeper-client/bin/zkCli.sh
./zookeeper-client/bin/zkCleanup.sh
./zookeeper-client/bin/zkServer-initialize.sh
./zookeeper-client/bin/zkEnv.sh
./zookeeper-client/bin/zkServer.sh
Notice: there are ZERO start/stop sh scripts..
In particular I am interested in the start-dfs.sh script that starts the namenode(s) , journalnode, and datanodes.
How to start DataNode
su - hdfs -c "/usr/lib/hadoop/bin/hadoop-daemon.sh --config /etc/hadoop/conf start datanode";
Github - Hortonworks Start Scripts
Update
Decided to hunt for it myself.
Spun up a single node with Ambari, installed HDP 2.2 (a), HDP 2.3 (b)
sudo find / -name \*.sh | grep start
Found
(a) /usr/hdp/2.2.8.0-3150/hadoop/src/hadoop-hdfs-project/hadoop-hdfs/src/main/bin/start-dfs.sh
Weird that it doesn't exist in /usr/hdp/current, which should be symlinked.
(b) /hadoop/yarn/local/filecache/10/mapreduce.tar.gz/hadoop/sbin/start-dfs.sh
The recommended way to administer your hadoop cluster would be via the administrator panel. Since you are working on Hotronworks distribution, it makes more sense for you to use Ambari instead.
Hi I am trying to run hadoop on a server that has hadoop installed but I have no idea the directory where hadoop resides. The server was configure by the server admin.
In order to load hadoop I use the use command from the dotkit package.
There may be several solutions but wanted to know where the hadoop package was installed, how to set up the $HADOOP_HOME variable, and how to approp run a hadoop streaming job, such as $HADOOP_HOME/bin/hadoop jar $HADOOP_HOME/mapred/contrib/streaming/hadoop-streaming.jar, aka, http://wiki.apache.org/hadoop/HadoopStreaming.
Thanks! any help would be greatly appreciated!
If you're using a cloudera distribution then it's most probably in /usr/lib/hadoop, otherwise it could be anywhere (at the discretion of your system admin).
There are some tricks you can use to try and locate it:
locate hadoop-env.sh (assuming that locate has been installed and updatedb has been run recently)
If the machine you're running this on is running a hadoop service (such as data node, job tracker, task tracker, name node), then you can perform a process list and grep for the hadoop command: ps axww | grep hadoop
Failing the above two, look for the hadoop root directory in some common locations such as: /usr/lib, /usr/local, /opt
Failing all this, and assuming your current user has the permissions: find / -name hadoop-env.sh
If you're install with rpm then it's most probably in /etc/hadoop.
Why don't you try:
echo $HADOOP_HOME
Obiviously the above env variable has to be set before you could even issue hadoop executables from anywhere on the box.