On Fri, Jul 28, 2023 at 7:34 PM tito via Dng <dng@???> wrote:

> On Fri, 28 Jul 2023 13:46:33 -0400
> Haines Brown <haines@???> wrote:
>
> > I would like to install OpenRC on my running Daedalus system. It is
> > simple enough to select it during installation of the OS, but what if
> > I want to install it on my running system? Does installation of the
> > openrc package simply replace sysV-Init and make openrc default? Is a
> > reboot needed?


definitely! see below


> > How would I revert to SysV-Init?
> Hi,
> have tried? on chimaera il looks easy:
>

so it does on Debian bookworm - up to the point where you stopped


> apt install openrc
> [...]

0 upgraded, 3 newly installed, 1 to remove and 0 not upgraded.
> Need to get 246 kB of archives.
> After this operation, 2,165 kB of additional disk space will be used.
> Do you want to continue? [Y/n]


and after that question the interesting part starts. What you generally
have to observe when replacing the init package in a running system is that
after the removal of the old package the binary of the running pid 1
process will be gone as well as any helper software that init needs to
cleanly shut down the system and you can't simply stop the old pid 1 init
process as all other processes of the running system were spawned from it.
The new init will not be able to perform a clean shutdown either or even
any shutdown at all, because it is not running yet.
Thus unless there are special precautions provided by the system you should
be prepared to reboot the hard way after installing the new init package
(and are really sure it has been installed properly). That means:

1) to safeguard against filesystem damage mount all viable partitions
read-only. This can be done by running the command "mount -a -o remount-ro"
or with a keystroke combination I don't remember if you have SysRq enabled
in the kernel.

2) power-cycle the system, i.e. remove the power supply and plug it in
again, preferrably after a short pause. Probably you also can use a hard
reboot option via SysRq here.