Re: Debianization

[Didier Kryn]

Le 21/04/2018 à 18:19, Guillaume Perréal a écrit :

Le 21/04/2018 à 12:28, Didier Kryn a écrit :
    May I humbly ask why you don't start with Devuan (which is Debian 
stripped out of systemd)? Of course it is less challenging than doing 
the job on Debian, but it would be wholehartedly applauded and tested 
by the Devuan community, while you shouldn't expect much recognition 
from Debian.


            Didier
I have tried to boot an Alpine Linux with s6-init and the set of of 
the services I wanted and it is quite a lot a work. I think writing a 
full replacement with shims and "translators" is an order of magnitude 
higher.


Guillaume.


    I'm a follower of musl and a supporter of static 
linking. I started to build my own musl-based Linux before Alpine was 
available and eventually achieved to build a functional native 
development platform. But it is too much work and I plan to try Alpine 
pretty soon :-)


    Whether starting from Alpine or Devuan, at least you don't have to 
fight against Systemd which has put metastases pretty much everywhere in 
the system. You start from sysvinit and just replace the rc scripts even 
with keeping sysv's init proper, at the beginning. A big part of the 
work is packaging and transitionning flawlessly from one system to the 
other when installing/removing the packages.


        Didier

Re: Debianization

[Avery Payne]

On Sat, Apr 21, 2018 at 4:27 AM, SZÉPE Viktor  wrote:

>
> Actually my first step of setting up a production Debian-based server is
> reverting back to SysVinit
> https://github.com/szepeviktor/debian-server-tools/blob/
> master/debian-setup.sh#L88-L90
> Currently I haven't reached a single boot, so it is a task for me to
> migrate the above listed services to *native* s6-rc.
>
> Are you looking for run files?  There are several stashed away in various
repositories. Are you looking to have run files for every Debian service
possible?  That is a large task - on Debian 7 there were ~ 900 packages
that would leave rc scripts in /etc/init.d that were not one-shots, so you
have your work cut out.  I'm sure the list has grown since then.

I humbly suggest the following:

1. convert to SysV, and start out using stock rc scripts inside /etc/init.d
2. create Debian packages for s6, and install from the packages.
3. determine where you are locating the directories "service", "svc", and
"svcdef" (or whatever you are calling them) and try to comply with Debian's
rules.  For Debian, I suggest you create the directories /etc/svc and
/etc/svcdef, and then make a symlink from /service pointing to /etc/svc,
which I'm sure is not 100% "Debian acceptable" but is probably the right
thing to do.
4. decide on a logging layout.  You can do anything you want, but to keep
things similar, I suggest that all services that don't do their own logging
receive a s6-log instance, using the T option instead of t (since Debian
doesn't support TAI64N), and that your s6-log output be directed to a file
inside of a directory named /var/log/{service name}.
5. decide on a strategy to replace syslog.  Maybe something that provides
/dev/log.  Not 100% needed, but nice to have.
6. decide on a strategy for udev.  You will need it to run at startup,
prior to switching run levels; I suggest a one-shot that sets up all of the
device names at startup, and a separate longrun that supervises udevd in
normal use.  Not optimal, but it should suffice.
7. decide on a strategy for dbus.  You can easily make a service definition
for it, but you'll have the unpleasant discovery of finding consolekit,
policykit, rtkit, and others being unsupervised. (some day I will peer into
the bowels of dbus and see if there is a way to make it play nice...)
8. decide on a strategy for pulseaudio, which is a worse pain than udev and
dbus together.  You'll have the fun choices like "it runs system wide but
desktop audio is buggy or fails", or "I don't supervise it but I have
desktop audio", or my favorite, "just suffer without it and install ALSA".
9. start writing run scripts.  Look around github for little repos here and
there, and look at what people are doing.  You can contact people in
private if you get stuck.  Be sure to bundle the scripts into a package
that can be re-installed.  Perhaps name it s6-debian-runscripts or
something similar.
10. if you are willing to put up with beta-grade software while you
transition, use rc-shim to replace the scripts in /etc/init.d one by one,
so you can cleanly boot with SysV AND have s6 supervising your services.  I
will warn you that it still has some rough edges, but it should be "good
enough" for the time being.  If you do decide to use rc-shim, you will want
to make a small modification that copies /etc/svcdef/{servicename} to
/etc/svc/{servicename} when it starts a service for the first time...
11. once you have run scripts for everything, you can make the move to a
pure s6 based system, and you don't need the rc-shim anymore, or SysV.  Yay!
12. please share your s6-debian-runscripts package, so that all Debian and
Devuan users can move to s6 as well. :)

That's quite the list to do, and I wish you the best of luck.

Re: Debianization

[Guillaume Perréal]

Le 21/04/2018 à 12:28, Didier Kryn a écrit :
    May I humbly ask why you don't start with Devuan (which is Debian 
stripped out of systemd)? Of course it is less challenging than doing 
the job on Debian, but it would be wholehartedly applauded and tested 
by the Devuan community, while you shouldn't expect much recognition 
from Debian.


            Didier
I have tried to boot an Alpine Linux with s6-init and the set of of the 
services I wanted and it is quite a lot a work. I think writing a full 
replacement with shims and "translators" is an order of magnitude higher.


Guillaume.

Re: Debianization

[SZÉPE Viktor]

Idézem/Quoting Didier Kryn :


Le 20/04/2018 à 07:48, SZÉPE Viktor a écrit :

Idézem/Quoting Colin Booth :


On Thu, Apr 19, 2018 at 11:10:33PM +, Laurent Bercot wrote:

Have any started (thinking about) packaging skalibs, execline and s6
the Debian policy-obeying way?


 What does that mean? If it's just FHS, skarnet.org follows FHS by
default, so there's no problem here. Are there other constraints
restricting what a Debian package can do?

It's technically a pile of things:
libs/skalibs (the .so)
lib-devel/skalivs-dev (the .a for compiling against
lang/execline
lib/libexecline (the .so)
lib-devel/libexecline-dev (the .a again)
and so on. I have sort-of complaint packages that I used to get my build
chain working for a project at work, but correctly separating stuff isa
chunk of work. Doable, just obnoxious.


In a previous message:


... into both .deb's and .rpm's using fpm without much fuss.


That much fuss includes 859 lintian tags e.g. gcc hardening, rc  
scripts for essential Debian packages, a systemd->s6 migration  
utility etc.

https://lintian.debian.org/tags.html

So basically I type apt-get install s6 and it makes systemd  
disappear, and all these basic services work after reboot:


cgroupfs-mount
console-setup.sh
cron
dbus
hwclock.sh
keyboard-setup.sh
kmod
networking
procps
rsync
rsyslog
ssh
udev

Is there a documentation how to turn e.g. 'networking' into an s6 rc?


SZÉPE Viktor, honlap üzemeltetés / Running your application
https://github.com/szepeviktor/debian-server-tools/blob/master/CV.md



    May I humbly ask why you don't start with Devuan (which is  
Debian stripped out of systemd)? Of course it is less challenging  
than doing the job on Debian, but it would be wholehartedly  
applauded and tested by the Devuan community, while you shouldn't  
expect much recognition from Debian.


            Didier


Thank you for the advise!
Actually my first step of setting up a production Debian-based server  
is reverting back to SysVinit

https://github.com/szepeviktor/debian-server-tools/blob/master/debian-setup.sh#L88-L90
Currently I haven't reached a single boot, so it is a task for me to  
migrate the above listed services to *native* s6-rc.




SZÉPE Viktor, honlap üzemeltetés / Running your application
https://github.com/szepeviktor/debian-server-tools/blob/master/CV.md
--
ügyelet/hotline: +36-20-4242498  s...@szepe.net  skype: szepe.viktor
Budapest, III. kerület

Re: Debianization

[Didier Kryn]

Le 20/04/2018 à 07:48, SZÉPE Viktor a écrit :

Idézem/Quoting Colin Booth :


On Thu, Apr 19, 2018 at 11:10:33PM +, Laurent Bercot wrote:

> Have any started (thinking about) packaging skalibs, execline and s6
> the Debian policy-obeying way?

 What does that mean? If it's just FHS, skarnet.org follows FHS by
default, so there's no problem here. Are there other constraints
restricting what a Debian package can do?

It's technically a pile of things:
libs/skalibs (the .so)
lib-devel/skalivs-dev (the .a for compiling against
lang/execline
lib/libexecline (the .so)
lib-devel/libexecline-dev (the .a again)
and so on. I have sort-of complaint packages that I used to get my build
chain working for a project at work, but correctly separating stuff isa
chunk of work. Doable, just obnoxious.


In a previous message:


... into both .deb's and .rpm's using fpm without much fuss.


That much fuss includes 859 lintian tags e.g. gcc hardening, rc 
scripts for essential Debian packages, a systemd->s6 migration utility 
etc.

https://lintian.debian.org/tags.html

So basically I type apt-get install s6 and it makes systemd disappear, 
and all these basic services work after reboot:


cgroupfs-mount
console-setup.sh
cron
dbus
hwclock.sh
keyboard-setup.sh
kmod
networking
procps
rsync
rsyslog
ssh
udev

Is there a documentation how to turn e.g. 'networking' into an s6 rc?


SZÉPE Viktor, honlap üzemeltetés / Running your application
https://github.com/szepeviktor/debian-server-tools/blob/master/CV.md



    May I humbly ask why you don't start with Devuan (which is Debian 
stripped out of systemd)? Of course it is less challenging than doing 
the job on Debian, but it would be wholehartedly applauded and tested by 
the Devuan community, while you shouldn't expect much recognition from 
Debian.


            Didier