httpd: apr_sockaddr_info_get() failed for “hostname”

When I start httpd service,I get a warning :

“Starting httpd: httpd: apr_sockaddr_info_get() failed for myservername, httpd: Could not reliably determine the server’s fully qualified domain name, using for ServerName”

This error is caused by the improper configuration of hostname of server,to fix it follow the steps below:
There are three methods for fixing, choose one as you preferred.
1- Edit Hosts File and add myservername declaration in the end of /etc/hosts :

$ sudo nano -w /etc/hosts localhost localhost.localdomain localhost4 localhost4.l$
::1 localhost localhost.localdomain localhost6 localhost6.localdoma$ myserver

2- Only edit httpd.conf :

$ sudo nano -w /etc/apache2/httpd.conf

3- Edit network :

$ sudo nano -w /etc/sysconfig/network

4-  Verify :

$ hostname
$ hostname -f