Re: [DNG] startup scripts (was dng@lists.dyne.org)
On 18/07/15 12:42, Fred DC wrote: > On 18/07/2015 10:49, Laurent Bercot wrote: >> >> Believe me, providing sysv-rc compatibility when you're working on >> a supervision suite is no small feat: the paradigm is very different, >> >> . If it was easy, we would have provided compatibility packages >> long ago, and supervision would already rule the world (with a gentle, >> good hand). >> > > I am not saying that runit is better as s6 - all I want to point out is > that debian runit, until recently, intergrates fairly well with sysv-rc. > > Yes, the supervised services do need their own service-framework with > their own scripts. For me (as a simple user) the hard nut to crack was > to write stubs and a script which during a debian-update translate the > inet-calls to sv-calls without insserv telling me to take a hike. I solved this issue by diverting the original package's startup script and replacing it with a symlink to /usr/bin/sv in the postinst's scripts. As an example here is the postinst script of my nginx-run package: http://parad0x.org/git/debian-run/nginx-run/tree/debian/postinst I also patched insserv to recognise and ignore symlinks to /usr/bin/sv to make this work nicely. The patch is here: http://parad0x.org/git/debian-run/insserv/ Native support for alternative init systems would hopefully obsolete the need for these kind of tweaks, but in the meantime they make for a very smooth integration of runnit with debian. I haven't tried s6 yet, but it's on my bucket list. -- Mat ___ Dng mailing list Dng@lists.dyne.org https://mailinglists.dyne.org/cgi-bin/mailman/listinfo/dng
Re: [DNG] startup scripts (was dng@lists.dyne.org)
The boot scripts can be somewhat universal, but not always. Runit and s6 require some very special and specific service and boot scripts for init, plus a lot of custom service scripts. These are what need the most attention. The init stage scripts are going to be unique to each init system as well. Stage 1 in Runit is the one shot primary system startup sequences, while in s6, stage 1 is the init system script itself. These can be translated between each as needed, but each init should be made to have it's own stuff. In the long term, the scripts will not need much maintenance if they are done correctly. Sent from my Windows Phone From: Didier Kryn<mailto:k...@in2p3.fr> Sent: 7/18/2015 6:44 AM To: dng@lists.dyne.org<mailto:dng@lists.dyne.org> Subject: Re: [DNG] startup scripts (was dng@lists.dyne.org) Le 18/07/2015 12:43, KatolaZ a écrit : > On Sat, Jul 18, 2015 at 09:52:18AM +0200, Didier Kryn wrote: > > [cut] > >> Further more, a method could be agreed on to tell the script if >> the daemon is going to be supervised or not, and we would then need >> only one script for all cases. >> >> For example, providing "supervised-start" and >> "supervised-reload" in addition to the other cases could do the job. >> For safety, the scripts could check a file which tells them which >> supervisor is calling them. >> >> What do you think? >> Didier > > How do you support init scripts for several init systems for all the > daemons that could be installed in a distro like Devuan? Who should do > this work? Who should keep things updated and synchronised to allow > the whole process to be neat and clean? Guys, if one apt-get installs > --force-yes the default editor, and things go wrong, it's not a big > issue. If we do the same on init, it's back to dice > rolling... (cit. moria). > > My2Cents > > KatolaZ > Dear KatolaZ, I probably didn't express things properly. My idea was precisely a way to workaround the issue you say. The idea was to modify the existing sysv-init scripts so that, while remaining 100% compatible with sysv-init, they become also usable by supervisors. If it proved possible and a standard method was agreed on, then I am convinced the authors of these daemons would do it upstream. Alas, supervision experts don't think it is possible :-( Didier ___ Dng mailing list Dng@lists.dyne.org https://mailinglists.dyne.org/cgi-bin/mailman/listinfo/dng ___ Dng mailing list Dng@lists.dyne.org https://mailinglists.dyne.org/cgi-bin/mailman/listinfo/dng
Re: [DNG] startup scripts (was dng@lists.dyne.org)
Le 18/07/2015 12:43, KatolaZ a écrit : On Sat, Jul 18, 2015 at 09:52:18AM +0200, Didier Kryn wrote: [cut] Further more, a method could be agreed on to tell the script if the daemon is going to be supervised or not, and we would then need only one script for all cases. For example, providing "supervised-start" and "supervised-reload" in addition to the other cases could do the job. For safety, the scripts could check a file which tells them which supervisor is calling them. What do you think? Didier How do you support init scripts for several init systems for all the daemons that could be installed in a distro like Devuan? Who should do this work? Who should keep things updated and synchronised to allow the whole process to be neat and clean? Guys, if one apt-get installs --force-yes the default editor, and things go wrong, it's not a big issue. If we do the same on init, it's back to dice rolling... (cit. moria). My2Cents KatolaZ Dear KatolaZ, I probably didn't express things properly. My idea was precisely a way to workaround the issue you say. The idea was to modify the existing sysv-init scripts so that, while remaining 100% compatible with sysv-init, they become also usable by supervisors. If it proved possible and a standard method was agreed on, then I am convinced the authors of these daemons would do it upstream. Alas, supervision experts don't think it is possible :-( Didier ___ Dng mailing list Dng@lists.dyne.org https://mailinglists.dyne.org/cgi-bin/mailman/listinfo/dng
Re: [DNG] startup scripts (was dng@lists.dyne.org)
On 18/07/2015 12:42, Fred DC wrote: I am not saying that runit is better as s6 - all I want to point out is that debian runit, until recently, intergrates fairly well with sysv-rc. The reason why it does is that it compromises on supervision. I don't know how debian runit is packaged, but I'm willing to bet that in this model, for instance, udevd is not supervised by runsv. See the first FAQ entry at http://skarnet.org/software/s6-linux-init/quickstart.html for details. Yes, the supervised services do need their own service-framework with their own scripts. For me (as a simple user) the hard nut to crack was to write stubs and a script which during a debian-update translate the inet-calls to sv-calls without insserv telling me to take a hike. I succeded because I accepted the fact that I have the standard lsb-sysv-scripts in /etc/init.d/ and that the underlying dpkg-system does use these scripts. I'm currently working on a service manager for s6 that can ease the transition between a sysv-rc style and a supervision style, i.e. it can use the sysv-rc scripts at first, and switch to a supervision style service by service when package maintainers start supporting it. It still doesn't make things easy, but I believe it makes the support envisionable for a distribution, because the workload does not have to be done all at once - it can be spread over time. BTW, and what about rcS, rc0 and rc6a complete re-write? That's my ultimate goal, but it's obviously not feasible without a gradual and smooth transition plan, which I'm elaborating now. Naah... KISS... use what we got! Strictly my opinion. KISS all right, but sysv-rc is not SS, and most importantly, it's not correct. "Use what we got" is a good strategy to organize work and focus on the urgent things first, but at some point, when "what we got" is insufficient, it needs to be addressed. Take your time, and I'll be there when distributions are ready to tackle the issue. :) -- Laurent ___ Dng mailing list Dng@lists.dyne.org https://mailinglists.dyne.org/cgi-bin/mailman/listinfo/dng
Re: [DNG] startup scripts (was dng@lists.dyne.org)
On Sat, Jul 18, 2015 at 09:52:18AM +0200, Didier Kryn wrote: [cut] > > Further more, a method could be agreed on to tell the script if > the daemon is going to be supervised or not, and we would then need > only one script for all cases. > > For example, providing "supervised-start" and > "supervised-reload" in addition to the other cases could do the job. > For safety, the scripts could check a file which tells them which > supervisor is calling them. > > What do you think? > Didier How do you support init scripts for several init systems for all the daemons that could be installed in a distro like Devuan? Who should do this work? Who should keep things updated and synchronised to allow the whole process to be neat and clean? Guys, if one apt-get installs --force-yes the default editor, and things go wrong, it's not a big issue. If we do the same on init, it's back to dice rolling... (cit. moria). My2Cents KatolaZ -- [ Enzo Nicosia aka KatolaZ --- GLUG Catania -- Freaknet Medialab ] [ me [at] katolaz.homeunix.net -- http://katolaz.homeunix.net -- ] [ GNU/Linux User:#325780/ICQ UIN: #258332181/GPG key ID 0B5F062F ] [ Fingerprint: 8E59 D6AA 445E FDB4 A153 3D5A 5F20 B3AE 0B5F 062F ] ___ Dng mailing list Dng@lists.dyne.org https://mailinglists.dyne.org/cgi-bin/mailman/listinfo/dng
Re: [DNG] startup scripts (was dng@lists.dyne.org)
On 18/07/2015 10:49, Laurent Bercot wrote: > > Believe me, providing sysv-rc compatibility when you're working on > a supervision suite is no small feat: the paradigm is very different, > > . If it was easy, we would have provided compatibility packages > long ago, and supervision would already rule the world (with a gentle, > good hand). > I am not saying that runit is better as s6 - all I want to point out is that debian runit, until recently, intergrates fairly well with sysv-rc. Yes, the supervised services do need their own service-framework with their own scripts. For me (as a simple user) the hard nut to crack was to write stubs and a script which during a debian-update translate the inet-calls to sv-calls without insserv telling me to take a hike. I succeded because I accepted the fact that I have the standard lsb-sysv-scripts in /etc/init.d/ and that the underlying dpkg-system does use these scripts. I fully agree with Laurent's sentiments that it is not as simple... IMHO, it is doeable to make it compatible against an init-system wich is the required default by the package-manager - but without an aggreed standard it will get out of hand. my 2cents Fred BTW, and what about rcS, rc0 and rc6a complete re-write? Naah... KISS... use what we got! Strictly my opinion. ___ Dng mailing list Dng@lists.dyne.org https://mailinglists.dyne.org/cgi-bin/mailman/listinfo/dng
Re: [DNG] startup scripts (was dng@lists.dyne.org)
On 18/07/2015 09:52, Didier Kryn wrote: There are two categories of launchers: supervisors and non-supervisors. Similarly, I think two scripts only are needed for every daemon: one for launching without supervision, alla sysv-init and one for launching from a supervisor. Just two, not one per every launcher/supervisor. Further more, a method could be agreed on to tell the script if the daemon is going to be supervised or not, and we would then need only one script for all cases. For example, providing "supervised-start" and "supervised-reload" in addition to the other cases could do the job. For safety, the scripts could check a file which tells them which supervisor is calling them. What do you think? It's a bit more complicated than that. Supervision suites don't only take a script, they take a whole "service directory" where the configuration is stored. Which is a good thing, because it involves not only the daemon-starting script, but cleanup procedures, readiness notification procedures, and other details on how to properly supervise the daemon. The daemon-starting script itself is launched by the supervisor without arguments, so you cannot call it as "foo supervised-start". You could provide one unique script for every daemon that does just what you suggest, but you would still have to provide a complete service directory in addition to it. And the service directory isn't exactly the same depending on the chosen supervision suite. daemontools, runit, s6, perp and nosh all have subtly different options, so even if you have a common basis and simple daemons can use the same service directory with several supervision suites, when you get into advanced stuff such as readiness notification,configuration details must be handled differently. Believe me, providing sysv-rc compatibility when you're working on a supervision suite is no small feat: the paradigm is very different, and when you've had a taste of supervision, you realize how poor the sysv-rc model is and how hard it is to contort yourself to fit into the box. If it was easy, we would have provided compatibility packages long ago, and supervision would already rule the world (with a gentle, good hand). -- Laurent ___ Dng mailing list Dng@lists.dyne.org https://mailinglists.dyne.org/cgi-bin/mailman/listinfo/dng
Re: [DNG] startup scripts (was dng@lists.dyne.org)
Le 17/07/2015 21:38, ibid...@gmail.com a écrit : KatolaZ: > > > > >You guys talk about supporting half a dozen init systems like it > > > >was similar to providing half a dozen different editors, which > > > >believe me is not quite the case. This is true, because supporting an init system requires every package that provides a daemon to work with that init system's boot scripts. And you can't really define a single format for boot scripts, because that's a fundamental part of how an init system works. To be clear, let's concentrate on the part of init which is the concern: the daemon-launcher. I don't think things are as complex as is suggested by the comments I have read up to now. There are two categories of launchers: supervisors and non-supervisors. Similarly, I think two scripts only are needed for every daemon: one for launching without supervision, alla sysv-init and one for launching from a supervisor. Just two, not one per every launcher/supervisor. Further more, a method could be agreed on to tell the script if the daemon is going to be supervised or not, and we would then need only one script for all cases. For example, providing "supervised-start" and "supervised-reload" in addition to the other cases could do the job. For safety, the scripts could check a file which tells them which supervisor is calling them. What do you think? Didier ___ Dng mailing list Dng@lists.dyne.org https://mailinglists.dyne.org/cgi-bin/mailman/listinfo/dng
