How to protect /etc/resolv.conf after reboot? (use the chattr command)

 How to protect /etc/resolv.conf after reboot? 

Once upon a time I had a problem with DNS configuration. Every reboot, the file /etc/resolv.conf was rewrite to from Network Manager. 

How to repair? 

We can use chattr command. 

so: 

lsattr - list of atributes 

chattr +i /etc/resolv.conf

-- after this option, the file not will be overwritten. 

In linux console: 

1) vi /etc/resolv.conf

# DNS server

nameserver 8.8.8.8

nameserver 8.8.4.4

2) chattr +i /etc/resolv.conf

3) reboot the server 

-- after reboot: 

[root@openstackstudy ~]# cat /etc/resolv.conf

# Generated by NetworkManager

nameserver 8.8.8.8

nameserver 8.8.4.4