Re: what init systems do you use ?

From: multiplexd <>
Date: Mon, 13 May 2019 20:13:29 +0100


On Fri, May 03, 2019 at 02:53:21AM +0200, Jeff wrote:
> what init systems do this list's subscribers use ?

I saw Guillermo's reply up-thread, so I thought I'd add my own two cents. My
main workstation at present is a Debian 9 box booted with s6 and s6-rc, with
system setup and teardown (i.e. stages 1 and 3) handled by some execline scripts
heavily adapted from those generated by s6-linux-init-maker 0.4.x.x.

It's been nearly two years since I set this up, so I don't recall all the
details, but I started out with a sysvinit Debian 9 system, and
reverse-engineered the boot sequence, which included a by-hand conversion of all
the necessary /etc/init.d scripts into s6-rc service definitions.

The boot process follows the general flow to be expected from a system using
s6-svscan as PID 1. The stage 1 script sets up an initial service directory,
spawns the script which starts stage 2 and then exec's into s6-svscan. Most of
the runtime state configuration and management is then handled through s6-rc in
stage 2. Stage 3 involves deactivating all the s6-rc managed services and then
signalling the PID 1 s6-svscan, which execs into a script which kills the
remaining processes, unmounts filesystems and then performs a halt, poweroff, or
reboot as necessary.

The particulars of the configuration I'm using are generally not portable to
other machines though, as it was a proof-of-concept I came up with a year or two
or go for a different system, which I then ported to my current workstation,
which was set up in a very similar manner. I've also had to make it largely
signal-compatible with sysvinit, as apt(8) sometimes attempts to reload the init
configuration upon package changes. The signal used to request a configuration
reload from sysvinit is SIGUSR1 if I recall correctly, however the default
behaviour of the version of s6-linux-init-maker I was using at the time was to
power off the machine upon receiving SIGUSR1 in PID 1, so I had to change the
signal configuration for s6-svscan.

That being said, it's been very stable and has largely stayed out my way, so
it's been worth the initial setup effort in the long run.

Received on Mon May 13 2019 - 19:13:29 UTC

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