I tried Fedora Linux for a few months in 2014. I got those "... job is running ..." or "... job is starting ..." messages when restarting / booting and the whole system stopped responding for more than five minutes.
These messages were largely the results of systemd.
systemd cannot be uninstalled without serious consequences. systemd is the default initialization system and all other spectacular control tools. systemd has replaced the former initialization system on Fedora Linux and subsequently the initialization system on Debian Linux.
Debian Linux is suffering because of the replacement. Starting / restarting / stopping the system cannot show reliable results any more.
OpenRC is an alternative initialization system and is compatible with the old initialization system on Debian. I am trying to switch to OpenRC.
The good thing of OpenRC is: I can choose to stop the parallel start function. The parallel start function enables services to start at the same time.
Disabling the parallel start feature will lead to starting services one by one. Starting services one by one is good and stable. "No freezing machine. No hanging. "
systemd forces the parallel start of services. There is no option to stop the parallel start in systemd. Unpredictable hanging occurs. Debian 8 uses systemd. Debian 8 is no longer a stable system because of adopting systemd. If you need a stable system, Debian 8 is not for you. You might need to downgrade to Debian 7.
Debian 7 starts services one by one at boot time. Debian 7 is good.
OpenRC starts services one by one at boot time. OpenRC is used on Gentoo Linux I am trying to test and use. I have restarted Gentoo Linux on my machine for twenty times smoothly. "No freezing at boot time."
For future upgrading and large-scale deployment, Debian 8 is not my choice.
Maybe I need Gentoo Linux and I need to learn to be an advanced administrator to use Gentoo Linux. The Gentoo Linux community provides a lot of documentation. Such documentation will definitely help me to learn quickly.
I need to set aside two machines for Gentoo Linux. One for testing and one for real deployment. To be an advanced administrator, I need to test the packages first before applying them on the production server.
On the contrary, "aptitude update && aptitude safe-upgrade" is used on Debian. I simply trust the maintainers. My trust is justified by experience. No problems after the "safe upgrade".
The key issue is: Debian 8 is not stable even in the "stable" release now. systemd causes a lot of stability headaches.
I will see if Gentoo Linux will help. OpenRC is good as in my experiment. Gentoo Linux uses OpenRC and not systemd by default. Definitely I need to consider Gentoo Linux.