# Ambari agent 2.7.x

[https://www.youtube.com/watch?v=JXgRu9vw9so](https://www.youtube.com/watch?v=JXgRu9vw9so)\
[https://www.youtube.com/watch?v=NR20r161eRI](https://www.youtube.com/watch?v=NR20r161eRI)

This video I will explain how to add a new host to existing hadoop cluster which is running on HDP 3.0 We use Ambari's add host wizard to do this task.Before adding the host make sure all basic pre-requisites are in place such as disabling firewall ,disable transparent huge page ,change vm swappiness and update /etc/hosts files.

One pre-requisites are done we can add this new host to cluster by using Ambari.

Adding pre-requisites that I used on this installation

CentOS / RHEL7

1.Change the run level to multi user text mode

systemctl get-default&#x20;

systemctl set-default multi-user.target

2.Change the hostname&#x20;

hostnamectl set-hostname "hostname"&#x20;

hostnamectl set-hostname master1.hadoop.com&#x20;

3.Disable firewall

systemctl disable firewalld systemctl status firewalld

4.Change VM Swappiness to 10 Add "vm.swappiness = 10" to file /etc/sysctl.conf

5.Disable SE Linux /etc/selinux/config and change from enhanced to disabled sed -i 's/SELINUX=enforcing/SELINUX=disabled/' /etc/selinux/config

6.Install and start NTP

yum yum -y install ntp&#x20;

systemctl enable ntpd&#x20;

systemctl start ntpd

7.Disable THP add these lines to /etc/rc.local&#x20;

echo "never" /sys/kernel/mm/transparent\_hugepage/enabled&#x20;

echo "never" /sys/kernel/mm/transparent\_hugepage/defrag

8.Update /etc/hosts file

Key Words How to add a node to hadoop cluster Adding new hosts to HDP cluster Hortonworks Dataplatform add host wizard Adding a new host to hrotonworks dataplatform cluster HDP 3.0 add a new host
