On Fri, Jan 10, 2020 at 06:18:07PM +0300, Benson Muite wrote: > Am rebuilding httpd from scratch to enable http2 and minimize extra modules > on Cent Os 8. Am having trouble understanding the spec file [0] and systemd > initialization [1][2][3] (these are very similar to those extracted from > [4]). Why are 3 scripts needed to start the service and why is a pid setting > not needed as used in the httpd.service file at [5]? The httpd-init.service handles some ssl cert generation on the first time a system runs, so httpd doesn't just die because there were missing SSL certs. They're self-signed. The httpd.socket unit lets you have systemd listen on port 80 and only start httpd if someone connects. THat's not a standard use, though. The httpd.service in the Fedora/CentOS systemd service unit uses Type=notify instead of Type=forking. While it's possible for systemd to keep track of all the subprocesses of a forking daemon, its difficult to determine if the service is "started". It uses the Pid file for that. With Type=notify, the daemon will send a notification back to systemd via sd_notify() when it is up, which makes it easier for systemd to know when a service has started, and start any dependencies or established that a target has been reached. You need a service that supports Type=notify, which httpd does. -- Jonathan Billings <billings at negate.org>