If you have already installed MRv1 following the steps in the previous section, you now need to uninstall hadoop-0.20-conf-pseudo before running YARN. Proceed as follows.

1. Stop the daemons:

   $ for x in `cd /etc/init.d ; ls hadoop-hdfs-*` ; do sudo service $x stop ; done 
   $ for x in 'cd /etc/init.d ; ls hadoop-0.20-mapreduce-*' ; do sudo service $x stop ; done

2. Remove hadoop-0.20-conf-pseudo:
   • On Red Hat-compatible systems:

     $ sudo yum remove hadoop-0.20-conf-pseudo hadoop-0.20-mapreduce-*

   • On SLES systems:

     $ sudo zypper remove hadoop-0.20-conf-pseudo hadoop-0.20-mapreduce-*

   • On Ubuntu or Debian systems:

     $ sudo apt-get remove hadoop-0.20-conf-pseudo hadoop-0.20-mapreduce-*

   In this case (after uninstalling hadoop-0.20-conf-pseudo) you can skip the package download steps below.

  Important:

If you have not already done so, install the Oracle Java Development Kit (JDK) before deploying CDH 5. Follow these instructions.

Download the CDH 5 Package

1. Click the entry in the table below that matches your Red Hat or CentOS system, choose Save File, and save the file to a directory to which you have write access (it can be your home directory).

   OS Version	Link to CDH 5 RPM
   RHEL/CentOS/Oracle 5	RHEL/CentOS/Oracle 5 link
   RHEL/CentOS/Oracle 6	RHEL/CentOS/Oracle 6 link
   RHEL/CentOS/Oracle 7	RHEL/CentOS/Oracle 7 link

2. Install the RPM.

   For Red Hat/CentOS/Oracle 5:

   $ sudo yum --nogpgcheck localinstall cloudera-cdh-5-0.x86_64.rpm 

   For Red Hat/CentOS/Oracle 6 (64-bit):

   $ sudo yum --nogpgcheck localinstall cloudera-cdh-5-0.x86_64.rpm

   For instructions on how to add a CDH 5 yum repository or build your own CDH 5 yum repository, see Installing CDH 5 On Red Hat-compatible systems.

Install CDH 5

1. (Optionally) add a repository key. Add the Cloudera Public GPG Key to your repository by running the following command:
   • For Red Hat/CentOS/Oracle 5 systems:

     $ sudo rpm --import https://archive.cloudera.com/cdh5/redhat/5/x86_64/cdh/RPM-GPG-KEY-cloudera

   • For Red Hat/CentOS/Oracle 6 systems:

     $ sudo rpm --import https://archive.cloudera.com/cdh5/redhat/6/x86_64/cdh/RPM-GPG-KEY-cloudera

2. Install Hadoop in pseudo-distributed mode: To install Hadoop with YARN:

   $ sudo yum install hadoop-conf-pseudo

Download and install the CDH 5 package

1. Download the CDH 5 "1-click Install" package.

   Download the rpm file, choose Save File, and save it to a directory to which you have write access (for example, your home directory).

2. Install the RPM:

   $ sudo rpm -i cloudera-cdh-5-0.x86_64.rpm

   For instructions on how to add a CDH 5 SLES repository or build your own CDH 5 SLES repository, see Installing CDH 5 On SLES systems.

Install CDH 5

1. (Optionally) add a repository key. Add the Cloudera Public GPG Key to your repository by running the following command:
   • For all SLES systems:

     $ sudo rpm --import https://archive.cloudera.com/cdh5/sles/11/x86_64/cdh/RPM-GPG-KEY-cloudera

2. Install Hadoop in pseudo-distributed mode: To install Hadoop with YARN:

   $ sudo zypper install hadoop-conf-pseudo 

Download and install the package

1. Download the CDH 5 "1-click Install" package:

   OS Version	Package Link
   Jessie	Jessie package
   Wheezy	Wheezy package
   Precise	Precise package
   Trusty	Trusty package

2. Install the package by doing one of the following:
   • Choose Open with in the download window to use the package manager.
   • Choose Save File, save the package to a directory to which you have write access (for example, your home directory), and install it from the command line. For example:

     sudo dpkg -i cdh5-repository_1.0_all.deb

  Note:

For instructions on how to add a CDH 5 Debian repository or build your own CDH 5 Debian repository, see Installing CDH 5 On Ubuntu or Debian systems.

Install CDH 5

1. (Optionally) add a repository key. Add the Cloudera Public GPG Key to your repository by running the following command:
   • For Ubuntu Lucid systems:

     $ curl -s https://archive.cloudera.com/cdh5/ubuntu/lucid/amd64/cdh/archive.key | sudo apt-key add -

   • For Ubuntu Precise systems:

     $ curl -s https://archive.cloudera.com/cdh5/ubuntu/precise/amd64/cdh/archive.key | sudo apt-key add -

   • For Debian Squeeze systems:

     $ curl -s https://archive.cloudera.com/cdh5/debian/squeeze/amd64/cdh/archive.key | sudo apt-key add -

2. Install Hadoop in pseudo-distributed mode: To install Hadoop with YARN:

   $ sudo apt-get update 
   $ sudo apt-get install hadoop-conf-pseudo

For YARN, a pseudo-distributed Hadoop installation consists of one host running all five Hadoop daemons: namenode, secondarynamenode, resourcemanager, datanode, and nodemanager.

• To view the files on Red Hat or SLES systems:

$ rpm -ql hadoop-conf-pseudo

• To view the files on Ubuntu systems:

$ dpkg -L hadoop-conf-pseudo

The new configuration is self-contained in the /etc/hadoop/conf.pseudo directory.

The Cloudera packages use the alternative framework for managing which Hadoop configuration is active. All Hadoop components search for the Hadoop configuration in /etc/hadoop/conf.

To start Hadoop, proceed as follows.

Step 1: Format the NameNode.

Before starting the NameNode for the first time you must format the file system.

$ sudo -u hdfs hdfs namenode -format

Make sure you perform the format of the NameNode as user hdfs. You can do this as part of the command string, using sudo -u hdfs as in the command above.

  Important:

In earlier releases, the hadoop-conf-pseudo package automatically formatted HDFS on installation. In CDH 5, you must do this explicitly.

$ for x in `cd /etc/init.d ; ls hadoop-hdfs-*` ; do sudo service $x start ; done

$ sudo /usr/lib/hadoop/libexec/init-hdfs.sh

$ sudo -u hdfs hadoop fs -ls -R /

...
drwxrwxrwt - hdfs supergroup 0 2012-05-31 15:31 /tmp
drwxr-xr-x - hdfs supergroup 0 2012-05-31 15:31 /tmp/hadoop-yarn
drwxrwxrwt - mapred mapred 0 2012-05-31 15:31 /tmp/hadoop-yarn/staging
drwxr-xr-x - mapred mapred 0 2012-05-31 15:31 /tmp/hadoop-yarn/staging/history
drwxrwxrwt - mapred mapred 0 2012-05-31 15:31 /tmp/hadoop-yarn/staging/history/done_intermediate
drwxr-xr-x - hdfs supergroup 0 2012-05-31 15:31 /var
drwxr-xr-x - hdfs supergroup 0 2012-05-31 15:31 /var/log
drwxr-xr-x - yarn mapred 0 2012-05-31 15:31 /var/log/hadoop-yarn
...

$ sudo service hadoop-yarn-resourcemanager start
$ sudo service hadoop-yarn-nodemanager start 
$ sudo service hadoop-mapreduce-historyserver start

$ sudo -u hdfs hadoop fs -mkdir /user/<user>
$ sudo -u hdfs hadoop fs -chown <user> /user/<user>

$ sudo -u hdfs hadoop fs -mkdir /user/$USER
$ sudo -u hdfs hadoop fs -chown $USER /user/$USER

1. Create a home directory on HDFS for the user who will be running the job (for example, joe):

   $ sudo -u hdfs hadoop fs -mkdir /user/joe 
   $ sudo -u hdfs hadoop fs -chown joe /user/joe

   Do the following steps as the user joe.

2. Make a directory in HDFS called input and copy some XML files into it by running the following commands in pseudo-distributed mode:

   $ hadoop fs -mkdir input
   $ hadoop fs -put /etc/hadoop/conf/*.xml input
   $ hadoop fs -ls input
   Found 3 items:
   -rw-r--r-- 1 joe supergroup 1348 2012-02-13 12:21 input/core-site.xml
   -rw-r--r-- 1 joe supergroup 1913 2012-02-13 12:21 input/hdfs-site.xml
   -rw-r--r-- 1 joe supergroup 1001 2012-02-13 12:21 input/mapred-site.xml

3. Set HADOOP_MAPRED_HOME for user joe:

   $ export HADOOP_MAPRED_HOME=/usr/lib/hadoop-mapreduce

4. Run an example Hadoop job to grep with a regular expression in your input data.

   $ hadoop jar /usr/lib/hadoop-mapreduce/hadoop-mapreduce-examples.jar grep input output23 'dfs[a-z.]+'

5. After the job completes, you can find the output in the HDFS directory named output23 because you specified that output directory to Hadoop.

   $ hadoop fs -ls 
   Found 2 items
   drwxr-xr-x - joe supergroup 0 2009-08-18 18:36 /user/joe/input
   drwxr-xr-x - joe supergroup 0 2009-08-18 18:38 /user/joe/output23

   You can see that there is a new directory called output23.

6. List the output files.

   $ hadoop fs -ls output23 
   Found 2 items
   drwxr-xr-x - joe supergroup 0 2009-02-25 10:33 /user/joe/output23/_SUCCESS
   -rw-r--r-- 1 joe supergroup 1068 2009-02-25 10:33 /user/joe/output23/part-r-00000

7. Read the results in the output file.

   $ hadoop fs -cat output23/part-r-00000 | head
   1 dfs.safemode.min.datanodes
   1 dfs.safemode.extension
   1 dfs.replication
   1 dfs.permissions.enabled
   1 dfs.namenode.name.dir
   1 dfs.namenode.checkpoint.dir
   1 dfs.datanode.data.dir