(98)Address already in use: make sock: could not bind to address 0.0.0.0:80

Issue

# service apache2 start

[....] Starting web server: apache2(98)Address already in use: make_sock: could not bind to address [::]:80
(98)Address already in use: make_sock: could not bind to address 0.0.0.0:80
no listening sockets available, shutting down
Unable to open logs
Action 'start' failed.
The Apache error log may have more information.
 failed!

Mitigation

Step 1

# netstat -ltnp | grep ':80'

tcp6       0      0 :::80                   :::*                    LISTEN      25585/apache2

Step 2

# kill -9 25585

Step 3

# service apache2 start

[ ok ] Starting web server: apache2.