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Ubuntu To Switch To systemd

Posted by Soulskill on from the follow-the-leader dept.

GuerillaRadio writes "Following the decision for Debian to switch to the systemd init system, Ubuntu founder and SABDFL Mark Shuttleworth has posted a blog entry indicating that Ubuntu will now follow in this decision. 'Nevertheless, the decision is for systemd, and given that Ubuntu is quite centrally a member of the Debian family, that's a decision we support. I will ask members of the Ubuntu community to help to implement this decision efficiently, bringing systemd into both Debian and Ubuntu safely and expeditiously.'"

11 of 279 comments (clear)

  1. Good...? by Kagetsuki · · Score: 5, Insightful

    I think it's good Shuttleworth was able to suck up his pride and go along with this decision to prevent fragmentation. I do however call the original decision slightly into question, but that's only because I've gotten sort of used to upstart. Hopefully anything good that was implemented in upstart but was not in systemd will make its way over.

    1. Re:Good...? by fishybell · · Score: 5, Insightful
      Having switched from System V to upstart to systemd I can safely say that yes, systemd is better for a full server or desktop OS. It has better reporting tools, it has more fine grained control, and it's fast. The trade off is complexity and size. There are many computer systems that the cost of switching to systemd will not bear fruit for a very long time (ex. embedded), but for servers and desktops that time has arrived.

      Learn to love systemd; it's here to stay and for good reason.

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    2. Re:Good...? by fishybell · · Score: 5, Informative

      System V has a scrict sense of a run level. For example, if you want a full desktop, run level 5 is often used, for a headless server, run level 3. What if you have a box that is headless most of the time, but you want to be able to run a full desktop sometimes? With System V you would change from run level 3 to run level 5 which would, depending on implimentation, stop and start services that are needed by both. Systemd instead has the concept of targets. Your full desktop target would have the headless server target as a dependency, and starting the full desktop would only run what isn't already running. You typically also have individual sevices that have dependencies. For example, you'd want your dhcp server to wait to start until the network has come online. In System V you have to define network as a number and make sure everything that depends on it has a bigger number and everything it depends on to have a smaller number. systemd's dependency model is also smart enough to start processes in parallel.

      All of that is just the most exposed part of systemd (to me at least). It also supplants other processes such as xinetd and udev. Instead of having three different ways to start processes based on system events (startup, port connection, hardware event) you have a single system to manage all three. It can get complicated (wasn't udev already complicated?) but the consistency is worth it.

      To keep all the consitency systemd provides a series of functions and magic variables. By magic variables I mean you set a list dependencies, which IMHO is less magic than the chkconfig comment lines in a typical System V init script. Both the magic variables and functions mean your typical service initaliation script is 10 lines instead of 100. While they may not be as obvious what's going on (a System V script is self-contained and can be ran on it's own) it is once you've become familiar with them.

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    3. Re:Good...? by amorsen · · Score: 5, Informative

      Indeed, journalctl is probably what I dislike the most about the current systemd stack. For one thing it is slow with full text search in large log files -- it is reasonably fast if you use the built-in column-specific search, but just running fgrep on it is not really feasible. In contrast, fgrep is ridiculously fast on modern systems as long as your log files stay below a few gigabytes in size. Also, the output of journalctl changes (mostly for the better) when you use it with pipes, which can be quite surprising.

      The other major problem with systemd is how difficult it is to debug boot failures. It is quite annoying when an fstab which was correct with upstart results in silent boot failure with systemd.

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  2. Re:Whats wrong with init? by EmperorArthur · · Score: 5, Interesting

    Lets face it, sysV init is complicated. Well, the theory behind the old linear start from init script 00 and move to init script 99 isn't, but the modern implementations and the scripts themselves are complicated. I mean you're doing dependency checking and a whole bunch of other things in bash scripts. Compare that to a systemd service file, which is overall nice and readable. So, part of it is factoring out the logic from the variables. The other big thing is bash and the tools used by init scripts are like using a sledgehammer to tap in a finishing nail.

    I'm not going to say that systemd is perfect. I like the "unix" way which is to use small units that do one thing well instead of anything. That's part of the reason I see bash init scripts as too much for the job. Unfortunately, the systemd authors look like they want to throw in everything but the kitchen sink. Well, everything that they can't just port to kernel space that is. But that's the thing, Linux is a Monolithic kernel. Like it or not, the "Linux" way is to have one uber optimized thing with modules to handle everything.

    In the end, I just really like the ease of use of service files. Oh, and the stupidly fast boot time on my laptop is really nice. People who say boot times don't matter aren't living in the real world.

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  3. Re:Whats wrong with init? by causality · · Score: 5, Interesting

    "I know nothing about this software but I'm gonna bitch, complain and sling shit at it anyway. How dare they move my cheese!"

    - Typical Slashtard

    Knowledge of the new software is a separate (easier to cheaply ridicule, stay classy) question. The issue with systemd: it reeks of a solution looking for a problem.

    If the existing init systems were causing widespread grief I'd be much more receptive to it. So would just about anyone currently questioning systemd's rapid adoption. Right now the reason for installing it is "everyone else is adopting it as the new standard and it will be increasingly difficult to go against that standard." That's not the best of selling points. It's not like "wow all these problems and limitations I had been experiencing will finally go away!" like you get with truly sensible and evolutionary changes.

    If you think that shouldn't matter to anyone, you could explain why you think so. In the meantime, please make an effort to understand the viewpoint of those who disagree with you. Then you stand a real chance of actually addressing the issue, or at least of not embarassing yourself with smug hand-waving and knee-jerk dismissals based on your annoyance that everyone doesn't already agree with you.

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    It is a miracle that curiosity survives formal education. - Einstein
  4. why not the new thing? by dAzED1 · · Score: 5, Insightful

    There's this new thing called "init.d" which makes things really simple - you can start a system up and step through things, and though the boot takes 5 seconds instead of 1 second, that isn't really a problem.

    Once I read the original post about systemd, and all the other let's-invent-a-problem-to-fix nonsense surrounding init.d, I literally hung up my hat and stopped being a syseng. I was a unix guy starting in 93, so it was probably time anyway, but it was the straw that broke my back, as it were.As mentioned, the central responsibility of an init system is to bring up userspace. And a good init system does that fast. I especially "loved" this line: As mentioned, the central responsibility of an init system is to bring up userspace. And a good init system does that fast. No. A good init system does it reliably, with no drama and no politics. A good init system allows one to easily determine the state of a system, and doesn't assume things like GUIs and such. A good unix init system does all this with commands which can be piped and parsed easily with grep and awk - two things the original post about systemd actually complains about. The idea that a unix person would complain about grep and awk was so mind-boggling to me that...well, I just hung up the hat. You did all this nonsense, just to save a few seconds? Because what, the only thing linux is used for, is laptops? Meh.

  5. Re:Embedded uses something different anyway by dalias · · Score: 5, Insightful

    This is a fallacy. A shell script running on a non-bloated shell (e.g. Busybox ash) consumes less than 50k of dirty pages per instance. It would take at least 20-30 such scripts running to even come close to rivaling systemd's memory usage, and that's not even counting other resources systemd is consuming.

  6. Re:Embedded uses something different anyway by Anonymous Coward · · Score: 5, Informative

    I don't think very much embedded stuff will ever use systemd..

    I am using Angstrom, which uses systemd, for embedded stuff. Haven't had any problems with systemd, but haven't tried to do anything complex either. It gets stuff started at startup time, that's all I have needed.

  7. Re: by binarylarry · · Score: 5, Funny

    Well fuck it, lets rewrite the Linux kernel in bash!

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  8. Re:Whats wrong with init? by tlhIngan · · Score: 5, Interesting

    Lets face it, sysV init is complicated. Well, the theory behind the old linear start from init script 00 and move to init script 99 isn't, but the modern implementations and the scripts themselves are complicated. I mean you're doing dependency checking and a whole bunch of other things in bash scripts. Compare that to a systemd service file, which is overall nice and readable. So, part of it is factoring out the logic from the variables. The other big thing is bash and the tools used by init scripts are like using a sledgehammer to tap in a finishing nail.

    I'm not going to say that systemd is perfect. I like the "unix" way which is to use small units that do one thing well instead of anything. That's part of the reason I see bash init scripts as too much for the job. Unfortunately, the systemd authors look like they want to throw in everything but the kitchen sink. Well, everything that they can't just port to kernel space that is. But that's the thing, Linux is a Monolithic kernel. Like it or not, the "Linux" way is to have one uber optimized thing with modules to handle everything.

    Well, the BIG problem is maintenance. SysV scripts have both a S and K variant on when to run when switching levels, and you can bet very few people have it properly set up if you do switch levels. Enough so that switching levels is fraught with danger - you can probably start at level 1 (single user), and switch to 3, 4, or 5. Maybe you can get back to 1 because the extra demons get killed. Maybe.

    In the end, it's bit of a maintenance hassle, and while completely understandable, it's a nightmare.

    In fact, I'm guessing most utilities don't even bother handling the case - you just reboot and forget about it.

    After all, computers are good at doing stuff automatically - so stuff like maintaining which services should run at which runlevels should be automated - the init can figure out what it needs to start, what it needs to kill and the order based on dependencies. All the user needs to do is select what needs to run at what runlevel, and the tool does the rest.

    Then there are the various hacks to SysV - PID files (if so many tools need to know the daemon PID, why not have init actually do that work than requiring every script to do it manually?), the fact that state tracking isn't really in the system, and if you need services to relaunch on failure within limits, there ought to be a way to do it without requiring a trip to /etc/inittab to specify that fact.