Why Systemd?

[Snowhog]

Not sure if this/you have mentioned this, but a rather nice aspect of Systemd (the GUI app) is that it allows you to open/see everything it displays without having to do so 'as root'. You are only prompted to authenticate (provide your password) if you have made changes and you want to save them.

[GreyGeek]

I was continuing my self-studies of Systemd by following example commands given for it on this web page.

In 15.04 and 15.10 one could switch between Upstart and Systemd. When I installed 16.04, and added Neon on top of it, I assumed that I could do the same, so I followed the procedure used in 15.10 and attempted to switch to Upstart. The result was that I borked my installation because one cannot switch 16.04 from Systemd to Upstart in 16.04. That led me to believe that Systemd was started by the kernel first thing. Indeed, the systemd-analyze plot graph seemed to show just that:


That is, it was PID=1.

That's why the results from the following command stunned me:
ps -aef | grep [s]ystemd
Systemd has PID=318

PID=1 is /sbin/init

That is Upstart/SysVinit. So, systemd is setting on top of Upstart, which explains
Upstart has not been removed and can't be removed. Systemd is not yet ready to be PID=1.
It also explains why systemctl seems to be doing (some/a lot) of its work by calling init services,
even from the systemd-gui in Systemsettings5. Any why, when mysql is installed, for example,
one cannot control it using systemd-gui or systemctl.

:~$ [B]systemctl status mysql[/B]
● mysql.service
   Loaded: not-found (Reason: No such file or directory)
   Active: inactive (dead)

:~$ [B]systemctl status mysqld[/B]
● mysqld.service
   Loaded: not-found (Reason: No such file or directory)
   Active: inactive (dead)

:~$ [B]whereis mysqld[/B]
mysqld: /usr/sbin/mysqld /usr/share/man/man8/mysqld.8.gz
jerry@jerry-Aspire-7739:~$ ps -aef | grep [m]ysql
jerry     1789  1786  0 11:00 ?        00:00:03 /usr/sbin/mysqld --defaults-file=/home/jerry/.local/share/akonadi/mysql.conf --datadir=/home/jerry/.local/share/akonadi/db_data/ --socket=/tmp/akonadi-jerry.HXGeTN/mysql.socket
:~$

Even if, for the present, Systemd is using Upstart/init scripts in the background to do the heavy lifting, Systemd-gui is a convenient one-stop shopping center for all most of your service needs.

I'm looking forward to when Kubuntu drops Upstart completely and becomes a pure Systemd disto. That will probably depend on Debian and Ubuntu. I have not tried 16.10. Does anyone know what the PID=1 task is for that release?

[MoonRise]

Nice video. I wasn't in any camp on that one. I understood both sides so that just left me.... well, don't know as I really was in the middle on that one.

[TWPonKubuntu]

"The only constant is change itself"

I'll be following this thread and Systemd. It looks like the choices outside of this will become limited in the future...

[Snowhog]

So, instead of listening to the complainers I began researching Systemd itself.

Ah, taking the road less traveled! Good for you!

[GreyGeek]

When I first encountered systemd I was antagonistic towards it, as some of my earlier posts in this forum will show. Linus Torvald's rant two years ago against a former co-developer of Systemd, for "continually submitting code which breaks downstream packages" and he wasn't going to merge his future code, was the tipping point. However, when I began searching for a distro that did not feature Systemd or planned to go to it in a future release, I realized that there were NO other choices for me since I did not want to use Slackware or Gentoo. So, I greased up my 75 year old brain and set about to learn as much as I could absorb about Systemd. It's been in rapid development since 2010 (and under the radar much of that time) and a LOT of the online videos and documentation is too old or out of date to be helpful, so I began restricting myself to reading and viewing only sources made available this year.

It's been an eye-opener! SystemD has been called an "octopus" or "fungus" because its tentacles or rhizomes are creeping into every bit of Linux. And, it is! Whereas Upstart is a collection of sysVinit and previous shell scripts, each with their own script formatting and layout, varying from distro to distro and not standardized at all, Systemd is uniform across distros, with minor changes in unit names, but with the same conf structure for each unit. One can edit all units (services, targets, mounts, paths, etc...) in one location! When one install systemd-gui, along with kde-config-systemd and a couple of other packages, a very nice SystemD GUI appears in SystemSettings5. In that GUI one can control just about every aspect of a distro's operation. The rest of SystemSettings5 is to control various aspects of Plasma5 and some devices.

For example. For several months my wifi connection has been stable. There were some updates yesterday that didn't seem related to my wifi connection. However, this morning an old pattern appeared that had, in the past, forced me to use my cable connection instead. When the wifi connects the NetworkManager complains and immediately disconnects it. In the past, deleting my old ESSID configuration and redoing it didn't help, which was why I used my cable connection for the first couple of months I used 16.04. This morning, after a dozen of so connect-disconnect messages I opened SystemSettings5 and fired up the Systemd GUI. I went to the NetworkManager.service, right clicked on it and chose "restart". That was four hours ago. My wifi has been solid every since.

I suspect that even KDE, which has its config files spread throughout ~/.kde, ~/.local and ~/.config and SystemSettings, will get its act together and merge with Systemd, so folks don't have to go drilling down through hidden directories to find disconnected config files that have obtuse formatting and config demands.

On a distro wide basis, I can see a Linux distro being reduced to three basic components: the kernel, Systemd and the user interface, be it a console or a desktop.

As far as some who claim that Systemd is a "great unknown" that would be a haven for government spying then their only solution would be to use a distro that compiles all code from the source files. But to be sure that the government hasn't embedded a TSL-like hole in the code they would first have to examine every line of every source file to be sure it is free of embedded "doors". Except for security researchers paid to do that, I don't know of anyone else who has the time or the skill level to do that. As a retired programmer myself, even IF I devoted 8-10 hours every day scouring the Arch or Gentoo code I doubt that I would be able to look at all 800-1000 source files that comprise a bare-bones Arch or Gentoo release before the next release became available. I wouldn't have time to even compile the code before I ran the distro. Besides, that's what vetted repositories are for. One hundred and sixty people can do in a day what it would take one person 160 days to do.



The libc6 library is another matter:

Any Unix-like operating system needs a C library: the library which defines the ``system calls'' and other basic facilities such as open, malloc, printf, exit...

The history of Unix and various standards determine much of the interface of the C library. In general the GNU C Library supports the ISO C and POSIX standards. We also try to support the features of popular Unix variants (including BSD and System V) when those do not conflict with the standards. Different compatibility modes (selectable when you compile an application) allow the peaceful coexistence of compatibility support for different varieties of Unix.

I can see Systemd absorbing the functions that libc6 are currently required to do.

So, instead of listening to the complainers I began researching Systemd itself.

[whatthefunk]

Thanks for this. Good run down of some of the benefits of using it. Hard to find when everybody is arguing about how much it sucks...

[dequire]

Good intro video and launching point for those not familiar with systemd.

[GreyGeek]