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@xxxxxxxxxx>
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