Today at dawn I had a small problem with one instance of my application. I saw that Apache was using a lot of memory, and I decided to restart it with a /etc/init.d/apache2 restart . However, apache did not go up because some variables it uses (for the user and log file) were not being loaded.
At the end of the day, I saw that the /etc/apache2/envvars file was not loading, so I had to put its own variables in the Apache configuration file. At the end of the day, the question remains: why was this file no longer loaded?