Network Configuration

Configure Network

The Hadoop VM is set to use DHCP by default. If a static IP is desired, you may choose either of these options:

• Option 1 Use this utility:

  /root/setup/network_setup.sh

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• Option 2 Manually update file /etc/sysconfig/network-scripts/ifcfg-eth0. Below, is an example of a static IP setting:

  BOOTPROTO=static
  IPADDR=10.3.16.227
  NETMASK=255.255.0.0
  GATEWAY=10.3.30.254
  DNS1=10.3.110.224
  DNS2=10.3.110.104
  NM_CONTROLLED=no

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Then restart the network service or reboot the server for the changes to take effect. Command to restart the network:

systemctl restart network

Set the Hostname

To set a hostname for your Ambari server, run the command:

hostnamectl set-hostname <hostname>

In the above command, substitute the <hostname> variable for the actual hostname of your Ambari server. For example:

hostnamectl set-hostname node1.hadoop-server.company.com

This hostname must be configured for both forward and reverse DNS. The Ambari and Hadoop applications must be able to translate the hostname to its IP address and back in order to work properly.

Update /etc/hosts file

Note

This step is optional if the hostname resolution is done by your DNS.

Update the /etc/hosts file by adding, for each node, one entry of IP address and hostname. You will need to repeat this procedure in every cluster node.

Warning

The /etc/hosts file on ALL nodes must have the hostname and IP of ALL nodes in the Hadoop cluster.

Example of how your /etc/hosts file should look like:

127.0.0.1  localhost localhost.localdomain localhost4 localhost4.localdomain4
::1        localhost localhost.localdomain localhost6 localhost6.localdomain6
10.1.1.1   node1.hadoop-server.company.com
10.1.1.2   node2.hadoop-server.company.com
10.1.1.3   node3.hadoop-server.company.com
10.1.1.4   node4.hadoop-server.company.com
10.1.1.5   node5.hadoop-server.company.com

Where 10.1.1.1 is the IP address of the node1 with hostname node1.hadoop-server.company.com. The following line applies to a node2 in the same fashion, and so forth. The /etc/hosts file in this example is identical in node1, node2, node3, node4 and node5.

Tip

If you are using DHCP, the IP address can be obtained using the ifconfig command.

Caution

Do NOT set 127.0.0.1 to the hostname of the node VM. Hadoop host registration will fail.