Re: multiple scandir and rc database

From: Eric Vidal <eric_at_obarun.org>
Date: Mon, 13 Jun 2016 18:50:25 +0400

> If you're a distributor: don't do that. Distributions should not install
> anything in /usr/local.
> Also, if you're providing s6 as the base init system, you should have the
> execline binaries in the root filesystem, which means /bin. Because the user
> may choose to have /usr on a different filesystem.

I totaly agree with you but i do not have the choice, you import program is in conflict with import from imagemagick. So, under Archlinux system (i'm based on it) the bin directory is a symlinks to /usr/bin.
note : I think, you will have this trouble on a lot of distribution. you have importas program which do the same thing as import program, so perhaps you can remove the import program?!?


> > foreground { s6-hiercopy /etc/s6/user-serv /run/user }
>
> Do you need to perform that step every time your service restarts?
> It's idempotent, so you should put that in a separate oneshot, instead of
> in a run script.

hum, understood, make one thing per one thing :)
 
> > if { if { s6-mkdir -p -m 0755 /run/user-run/ } forbacktickx -p -0 i {
> > s6-ls -0 /run/user } import -u i foreground { s6-ln -s --
> > /run/user/${i} /run/user-run/ } }
 
> Same thing: that's idempotent, so put that in a separate oneshot.
> Besides, all that accomplishes is add another level of indirection.
> Why do you need /run/user-run with symlinks when you could just use
> /run/user ? /run/user is already a working copy of your user data in
> /etc/s6/user-serv, why do you need an additional directory where you're not
> adding anything meaningful ?
 
right, i don't need this

 
> > s6-envdir -I /run/user-run/service/.s6-svscan
>
> I don't think that does what you think it does. Nothing in .s6-svscan is
> meant to be read and put into environment variables.
 
ok, i misundertandood this, thanks

> > #!/usr/local/bin/execlineb -S0
> > s6-svscanctl -q -- /run/user-run/service
>
> That's not going to work. Your s6-svscan service is a longrun, so your
> supposed "down" file will be ignored; it's not doing anything, you should
> delete it.

my fault,it is not a down file but a finish file, type syntax error here :)

> What is happening is that your user s6-svscan is sent a SIGTERM when s6-rc
> decides it's time to bring it down. Which is the right thing to do.
>
> Note that you launched s6-svscan with -s, so what SIGTERM does depends on
> the contents of /run/user-run/service/.s6-svscan/SIGTERM. That's probably
> not a good idea for a s6-svscan instance that is not the main one. My
> suggestion would be to just remove the -s option in your run script.
>
>
> > The rc database bring down correctly the service declared on it but
> > the scandir do not want to stop.
>
> I suspect you don't have a script for SIGTERM, so s6-svscan is happily
> ignoring it. Just remove the -s option to s6-svscan and everything will work
> fine.

ok, removing the -s option do the stuff


> > However, i have a another trouble, when i try to launch some classic
> > service with the second scandir(or the first, it's equal) i have this
> > error on the log : _at_40000000575cf0bb05fd2e24 s6-supervise
> > syslogd-linux/log: warning: unable to spawn ./run - waiting 10
> > seconds _at_40000000575cf0c504c9de44 s6-supervise syslogd-linux:
> > warning: unable to spawn ./run - waiting 10 seconds
> > _at_40000000575cf0c504ca5f2c s6-supervise (child): fatal: unable to exec
> > run: No such file or directory _at_40000000575cf0c50660c63c s6-supervise
> > (child): fatal: unable to exec run: No such file or directory
>
> You have an invalid "syslogd-linux" service directory, with no run script.
> Same thing with syslogd-linux/log. Check what is happening to your run
> scripts.

i taken your original service from your s6 package, i do not have changing anything on it appart the s6-setuidgid at the log scripts that i defined with s6log according to my system. However, if i try with your klogd-linux service, the error is equal. So, this is the procedure i use, perhaps i make a mistake :

i copy the entire directory syslogd-linux to my running scandir /run/boot/service
then i enter this command on the console:
s6-svscanctl -an /run/boot/service

> > then i launch a s6-rc-init by a oneshot just after like this :
>
> Hmmm. This means that your user s6-svscan should notify readiness.
> It's difficult to have a s6-svscan service notify readiness, because how do
> you define readiness?
> - If it's just that the s6-svscan process has entered its main loop and can
> now receive signals and commands and process the scandir: that's easy to do,
> but doesn't mean much.
> - If it's that the whole supervision tree at the time of launch, i.e. all the
> early services, are ready: that's a bit harder to implement, it implies
> running s6-svwait -a on all early services. Which is doable, but requires
> the run script to be a bit more complex than the one you wrote.

for the moment i do not understand what you mean :(.
Well i cannot start another s6-svscan (for user) on the init file rather than by a oneshot, because i need to wait for a complete operational system. I don't find the solution to tell at all the service on the user s6-svscan to wait that the last oneshot service for the booting time must be ready(not sure i'm clear, difficult in english for me).

i would like to separate the database for the boot and a database for a user. to make this i need to create a s6-svscan directory which allow me to start a rc database. But same thing, if i put the command to launch the s6-svscan dir on the init file, the system is not ready.
-- 
Eric Vidal <eric_at_obarun.org>
Received on Mon Jun 13 2016 - 14:50:25 UTC

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