Apache is already set up as a service, since:
$ sudo update-rc.d apache2 defaults
System start/stop links for /etc/init.d/apache2 already exist.
But Apache isn't starting. How can I start debugging what is going wrong?
I'm running Linux Mint, so a Debian flavour.
Start by looking at the error log tail -15 /var/log/apache2/error.log
If that doesn't give a hint such as ports being unavailable or so, run apache2ctl -t to test your config.
If your config is good, check to see if any process is already bound to port 80 or 443 (which is probably the ports you want apache on). The last column of the output will be $PID/$process_name.
sudo netstat -tlpne | egrep ':(80|443)'
Alternatively, see if Apache is running but listening on other ports...
sudo netstat -tlpne | grep apache
If you still haven't sorted it out by now, it wouldn't hurt to check that Apache is configured to the domains you expect, so run apache2ctl -S and you should see a list of configured domains. If your domain/port combination isn't listed there, you'll want to sort out your config.
There're more still, but these will reveal many common configuration problems.
localhost in httpd.conf. Now that warning is not showing, but no joy. No, there isn't something running on 80/443. Yes, the syntax is correct. Yes, it's configured for my virtual domain. sudo service apache2 start after logging in still works fine to get it running.
You should be able to tell by tailing your system and apache logs. Usually located at /var/log/messages/ and /var/log/httpd|apache2/ respectively. Then troubleshoot using the provided messages.
/var/log/apache/ exists alright, but no logs were changed since my last boot.
Just try:
sudo update-rc.d apache2 enable
