In two previous posts I described the installation process for the 2.4.0 and the 0.20 releases of hadoop to the students of my class on on Big scale analytics.

I opted for a VM-based solution, so that most of hardware and OS issues students would face would be limited to installing and configuring the VM manager. For the records, I am running Mac OS X 10.10.5 and relying on VirtualBox 5.0.10.

First of all, I downloaded the ISO image for Ubuntu server 14.04 at the Ubuntu server download page and created a Linux-Ubuntu based VM in VirtualBox with 1GB RAM, a 8GB VDI-based HD (dynamically allocated), and a DVD preloaded with the Ubuntu server 14.04 ISO image. Then I ran the VM and followed all default installation options, except for keyboard layout (I use an italian keyboard). I did not install any additional software, with the exception of manual package installation support.

Once the system was up and running, I installed Hadoop following a mix of the instructions in the tutorials provided by Michael Noll, BigData Handler, and Rasesh Mori, that is what follows.

Some details about the examples: the host name is manhattan, with an administrator user with login name boss (that is, boss is a sudoer); three points (...) in a console are used in order to skip verbose output. Finally, a dollar sign ($) occurring at the beginning of a line denotes the bash prompt.

Setting up the environment

First of all, we need to be sure to work on an up-to-date system. This will probably be the case if the ISO image refers to the current version of Ubuntu server. Just to be sure, log in as the boss user and type the following commands.

boss@manhattan:~$ sudo apt-get update
boss@manhattan:~$ sudo apt-get upgrade

Moreover, it is advisable not to run Hadoop services through a general-purpose user, so the next step consists in adding a group hadoop and a user hadoop-user belonging to that group (for the purposes of this tutorial, all information requested by adduser may be left blank, except the password.

boss@manhattan:~$ sudo addgroup hadoop
boss@manhattan:~$ sudo adduser --ingroup hadoop hadoop-user

Installing Java

The next step consists in installing Java 8, for instance through the Webupd8 repository:

boss@manhattan:~$ sudo apt purge openjdk*
boss@manhattan:~$ sudo add-apt-repository -y ppa:webupd8team/java
boss@manhattan:~$ sudo apt update
boss@manhattan:~$ sudo apt install -y oracle-java8-installer

After having accepted the software license, we can check that the correct release has been installed:

boss@manhattan:~$ java -version
java version "1.8.0_66"

Finallly, the $JAVA_HOME environment variable should be properly set up:

boss@manhattan:~$ sudo sh -c 'echo "export JAVA_HOME=/usr" >> /etc/profile'
boss@manhattan:~$ source /etc/profile

Disable IPV6

Hadoop and IPV6 do not agree on the meaning of address, thus it is adivsable to disable IPV6 adding the following lines at the end of /etc/sysctl.conf (after having switched back to the boss user):

# disable ipv6
net.ipv6.conf.all.disable_ipv6 = 1
net.ipv6.conf.default.disable_ipv6 = 1
net.ipv6.conf.lo.disable_ipv6 = 1

After a system reboot the output of cat /proc/sys/net/ipv6/conf/all/disable_ipv6 should be 1, meaning that IPV6 is actually disabled.

Setup SSH

All communications with Hadoop are encrypted via SSH, thus the corresponding server should be installed:

boss@manhattan:~$ sudo apt-get install openssh-server

and the hadoop-user must be associated to a key pair and subsequently granting its access to the local machine:

boss@manhattan:~$ su - hadoop-user
hadoop-user@manhattan:~$ ssh-keygen -t rsa -P ""
Generating public/private rsa key pair.
The key's randomart image is:
hadoop-user@manhattan:~$ cat $HOME/.ssh/ >> $HOME/.ssh/authorized_keys

Now hadoop-user should be able to access via ssh to localhost without providing a password:

hadoop-user@manhattan:~$ ssh localhost
The authenticity of host 'localhost (::1)' can't be established.
Last login: ...


Download and install Hadoop

Download hadoop-2.7.1.tar.gz (the link points to a suggested apache mirror, thus feel free to change it into a nearest link), unpack it and move the results in /usr/local, adding a symlink using the more friendly name hadoop and changing ownership of the directory contents to the hadoop-user user:

boss@manhattan:~$ wget
boss@manhattan:~$ tar xzf hadoop-2.7.1.tar.gz
boss@manhattan:~$ rm hadoop-2.7.1.tar.gz
boss@manhattan:~$ sudo mv hadoop-2.7.1 /usr/local
boss@manhattan:~$ sudo ln -sf /usr/local/hadoop-2.7.1/ /usr/local/hadoop
boss@manhattan:~$ sudo chown -R hadoop-user:hadoop /usr/localhadoop-2.7.1/

Setup the dedicated user environment

Switch to the hadoop-user user and add the following lines at the end of ~/.bashrc:

# Set Hadoop-related environment variables
export HADOOP_PREFIX=/usr/local/hadoop
export HADOOP_HOME=/usr/local/hadoop
export HADOOP_CONF_DIR=${HADOOP_HOME}/etc/hadoop
# Native path
export HADOOP_OPTS="-Djava.library.path=$HADOOP_PREFIX/lib/native"
# Java path
export JAVA_HOME="/usr"
# Add Hadoop bin/ directory to PATH

In order to have the new environment variables in place, reload .bashrc:

hadoop-user@manhattan:~$ source .bashrc

Configure Hadoop

Before being able to actually use the hadoop file system it is necessary to modify some configuration files inside /usr/local/hadoop/etc/hadoop. All such files follow the an XML format, and the updates should concern the top-level node configuration (likely empty after the hadoop installation). Specifically:

  • in yarn-site.xml:
  • in core-site.xml:
  • in mapred-site.xml (likey to be created through cp mapred-site.xml.template mapred-site.xml):
  • in hdfs-site.xml:

This also requires to manually create the two directories specified in the last two value XML nodes:

hadoop-user@manhattan:~$ mkdir -p /usr/local/hadoop/yarn_data/hdfs/namenode
hadoop-user@manhattan:~$ mkdir -p /usr/local/hadoop/yarn_data/hdfs/datanode

Finally, set to /usr the JAVA_HOME variable in /usr/local/hadoop/etc/hadoop/

Formatting the distributed file system

The last step consists in formatting the file system, operation to be executed as hadoop-user:

hadoop-user@manhattan:~$ hdfs namenode -format
15/12/10 10:45:32 INFO namenode.NameNode: STARTUP_MSG: 
15/12/10 10:45:34 INFO common.Storage: Storage directory /usr/local/hadoop/yarn_data/hdfs/namenode has been successfully formatted.
15/12/10 10:45:34 INFO util.ExitUtil: Exiting with status 0
15/12/10 10:45:34 INFO namenode.NameNode: SHUTDOWN_MSG: 
SHUTDOWN_MSG: Shutting down NameNode at manhattan/

the (hopeful) successful result of this operation is specified within the (quite verbose) output: search for the text successfully formatted!

A few more steps and… that’s it!

Hadoop is now installed. Invoking the scripts and respectively start the distributed file system and the mapreduce daemons:

Starting namenodes on [localhost]
localhost: starting namenode, logging to /usr/local/hadoop-2.7.1/logs/hadoop-hadoop-user-namenode-manhattan.out
localhost: starting datanode, logging to /usr/local/hadoop-2.7.1/logs/hadoop-hadoop-user-datanode-manhattan.out
Starting secondary namenodes [] starting secondarynamenode, logging to /usr/local/hadoop-2.7.1/logs/hadoop-hadoop-user-secondarynamenode-manhattan.out
starting yarn daemons
starting resourcemanager, logging to /usr/local/hadoop/logs/yarn-hadoop-user-resourcemanager-manhattan.out
localhost: starting nodemanager, logging to /usr/local/hadoop-2.7.1/logs/yarn-hadoop-user-nodemanager-manhattan.out

Although it is possible to directly write on the hadoop file system root directory, it is more advisable to create the user directory for hadoop-user, because all relative paths will refer precisely to this directory:

hadoop-user@manhattan:~$ hdfs dfs -mkdir /user
hadoop-user@manhattan:~$ hdfs dfs -mkdir /user/hadoop-user

An absence of outputs from these command invokations means a successful directory creation, which also ensure that the distributed filesystem component of hadoop has been correctly installed. To test also the mapreduce component it is possible to run one of the example jobs distributed along with hadoop:

hadoop-user@manhattan:~$ hadoop jar /usr/local/hadoop/share/hadoop/mapreduce/hadoop-mapreduce-examples-2.7.1.jar pi 10 1000
Job Finished in 124.244 seconds
Estimated value of Pi is 3.14080000000000000000

Finally, to stop the hadoop daemons, simply invoke and

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