The reason is that Ubuntu is apache2, there is no httpd.conf file, all cannot be found.
My is ubuntu14.04 system, apache2 configuration file in/etc/apache2/apache2.conf,
If you are not in this directory, you can query by this command: Find/-name apache2.conf
Other classmates may not know the difference between these files, available and the enabled file, we can find the code in the last few lines of the apache2.conf configuration file,
Description enable.conf is a configuration file that is included, sites-available is designed to facilitate the storage of unused configurations, all site configurations, including temporary non-enabled sites,
The enabled configuration is the currently active site, enabling you to quickly enable deactivation. When you want to enable it, just copy it from available, and it's easier to switch it off or configure it.
Apache server configuration file not found under Ubuntu or Linux httpd.conf