When starting the web server, I get the error "sudo: unable to resolve host krl", why?

Question

ubuntu

I start my apache and an error occurs:

[email protected]:~/Projects/livestreet$ sudo service apache2 start
sudo: unable to resolve host krl
 * Starting web server apache2                                                                                       apache2: apr_sockaddr_info_get() failed for krl
apache2: Could not reliably determine the server's fully qualified domain name, using 127.0.0.1 for ServerName
                                                                                                              [ OK ]

Because of which? How to deal with it?

[email protected]:~/Projects/livestreet$ cat /etc/hosts
127.0.0.1	localhost

# The following lines are desirable for IPv6 capable hosts
::1     ip6-localhost ip6-loopback
fe00::0 ip6-localnet
ff00::0 ip6-mcastprefix
ff02::1 ip6-allnodes
ff02::2 ip6-allrouters

Answer 1

In /etc/hosts add the line:
127.0.0.1 krl