STEP 1: First Install HomeBrew, download it from http://brew.sh

```$ ruby -e "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install)"```

STEP 2: Install Hadoop
```
$ brew search hadoop
$ brew install hadoop
```

Hadoop will be installed at path /usr/local/Cellar/hadoop

STEP 3: Configure Hadoop:

Edit hadoop-env.sh, the file can be located at /usr/local/Cellar/hadoop/2.6.0/libexec/etc/hadoop/hadoop-env.sh where 2.6.0 is the hadoop version. Change the line


```export HADOOP_OPTS="$HADOOP_OPTS -Djava.net.preferIPv4Stack=true"```
to

```export HADOOP_OPTS="$HADOOP_OPTS -Djava.net.preferIPv4Stack=true -Djava.security.krb5.realm= -Djava.security.krb5.kdc=" ```
Edit Core-site.xml, The file can be located at /usr/local/Cellar/hadoop/2.6.0/libexec/etc/hadoop/core-site.xml add below config
```
<property>
<name>hadoop.tmp.dir</name>
<value>/usr/local/Cellar/hadoop/hdfs/tmp</value>
<description>A base for other temporary directories.</description>
</property>
<property>
<name>fs.default.name</name>
<value>hdfs://localhost:9000</value>
</property>
```

Edit mapred-site.xml, The file can be located at /usr/local/Cellar/hadoop/2.6.0/libexec/etc/hadoop/mapred-site.xml and by default will be blank  add below config
```
<configuration>
 <property>
  <name>mapred.job.tracker</name>
  <value>localhost:9010</value>
 </property>
</configuration>
```
Edit hdfs-site.xml, The file can be located at /usr/local/Cellar/hadoop/2.6.0/libexec/etc/hadoop/hdfs-site.xml add
```
<configuration>
 <property>
  <name>dfs.replication</name>
  <value></value>
 </property>
</configuration>
```
To simplify life edit a ~/.profile and add the following commands. By default ~/.profile might not exist.

```
alias hstart=<"/usr/local/Cellar/hadoop/2.6.0/sbin/start-dfs.sh;/usr/local/Cellar/hadoop/2.6.0/sbin/start-yarn.sh">
alias hstop=<"/usr/local/Cellar/hadoop/2.6.0/sbin/stop-yarn.sh;/usr/local/Cellar/hadoop/2.6.0/sbin/stop-dfs.sh">
```

and source it

```$ source ~/.profile```

Before running Hadoop format HDFS

```$ hdfs namenode -format```


STEP 4: To verify if SSH Localhost is working check for files ~/.ssh/id_rsa and the ~/.ssh/id_rsa.pub files. If they don’t exist generate the keys using below command

```$ ssh-keygen -t rsa```

Enable Remote Login: “System Preferences” -> “Sharing”. Check “Remote Login”
Authorize SSH Keys: To allow your system to accept login, we have to make it aware of the keys that will be used

```$ cat ~/.ssh/id_rsa.pub >> ~/.ssh/authorized_keys```

Test login.

```
$ ssh localhost
Last login: Fri Mar 6 20:30:53 2015
$ exit
```

STEP 5: Run Hadoop

```$ hstart```

and stop using

```$ hstop```