Hi there, (CC Steve Langsek, since he's maintainer/developer (?) of Upstart.) (I'm not on the debian-devel list, so please use reply to all.)
People, especially in the TC, have criticized that there are different protocols for systemd and upstart to specify things such as notifications and/or socket activation. Back before the voting there was actually quite a discussion on whether init system A could be made to support protocol of B and vice-versa. I think there are even bug reports against both upstart and systemd because of this. To solve this problem, I've created a small tool called cross-init-bridge. Its goal is to translate readiness notifications / socket activation from one init system to another. It currently supports systemd <-> upstart (in both directions), although the lowest common denominator is used (which for both features happens to be Upstart). Code: https://github.com/chris-se/cross-init-tools (License: GPLv3+) (See README file for details.) There are still a few kinks to be worked out, and somebody needs to review the code for security, but in principle it works, so one can actually run systemd-enabled daemons (notify, socket activation) on top of Upstart and vice-versa. To put the whole thing into a bit of a big picture perspective: Since Canonical has now decided that in the long term they will probably switch to systemd, it does not seem unlikely that at some point Upstart might not be relevant anymore. However, if that is to happen, that will take place in the distant future, because of Canonical's LTS commitment. In light of this, I think that tools for increasing compatibility between init systems can be really helpful, even if it might only be for a transitional period. Also, systemd does not run on non-Linux ports and will most likely not run on those anytime soon, if Debian wants to support those, they will have to make due with another init system. Currently, the only contenders for those ports are sysvinit and OpenRC. And for compatibility reasons, even on Linux sysvinit will have to be supported for quite a while now. But one of the main advantages of both systemd and Upstart (and also OpenRC) is that the init definitions (unit files, jobs, init scripts) are by *far* easier to maintain than those of sysvinit. The main reason for this thread is actually to somehow auto-generate init scripts from systemd unit files. So I could easily imagining improving upon the current bridge to support running systemd-enabled services on sysvinit, kind of like start-stop-daemon but also with some of the most commonly used features in systemd units, such as detecting readiness properly (-b in start-stop-daemon has a huge warning in the man-page because of this) and auto-creating sockets and then passing them via the socket activation protocol. Together with the debhelper to autogenerate sysvinit files that was suggested in this thread, I could easily imagine that already for Jessie package maintainance when it comes to init scripts could be simplified by quite a bit. Some services requiring very advanced features would obviously not work, because I don't really want to reimplement *all* of systemd's unit file options for this, but I do think that one could probably have something that targets 90% of unit files and only the other 10% (probably mostly early-boot-services) will need manually written init scripts. So two questions: 1. Is there any interest in at least the current version of the cross-init-bridge? If so, I'll add a proper build system, fix the known quirks/bugs, call that "0.1" and make a debian package out of it. (I'm not a DD, so somebody else will have to upload it. ;-)) 2. Is there any interest in the "big picture" idea? The improved version of my bridge would be complimentary to the debhelper proposed here, the design I'd chose is to NOT read unit files but have everything as command line arguments, and that the debhelper would generate the required arguments from the unit file. (That has the advantage that once generated, it's easier to debug those init scripts.) If that is the case, I'd volunteer to work on the improved version that can start daemons when started from sysvinit. Regards, Christian -- To UNSUBSCRIBE, email to debian-devel-requ...@lists.debian.org with a subject of "unsubscribe". Trouble? Contact listmas...@lists.debian.org Archive: http://lists.debian.org/53010e75.3040...@iwakd.de
