What is the most idle way for a hadoop cluster's FQDN policy?

[#1]

Here's hadoop cluster information in CentOS 6.7.

/etc/hosts

10.10.1.10 cm.hdp.com cm

10.10.1.11 nn01.hdp.com nn01

10.10.1.12 nn02.hdp.com nn02

10.10.1.13 yarn.hdp.com yarn

10.10.1.14 dn01.hdp.com dn01

10.10.1.15 dn02.hdp.com dn02

10.10.1.16 dn03.hdp.com dn03

In case of a node, nn01.hdp.com,

I wondering about HOSTNAME's value in '/etc/sysconfig/network'.

Following this link, it is recommend HOSTNAME pattern like that "FQDN".

https://docs.hortonworks.com/HDPDocuments/Ambari-2.4.1.0/bk_ambari-installation/content/edit_the_net...

Why is that HOSTNAME changed to FQDN?

I think, HOSTNAME value is not FQDN but HOSTNAME like this.

HOSTNAME=nn01

[#2 · Accepted solution]

You need to update in /etc/hosts as well.

1) /etc/sysconfig/network :- this used while internode communication

2) /etc/hosts while client connection this is going to use.

We need to set FQDN names on both file, this idle way