Re: [ptxdist] systemd: Using second offline update service beside rc-once in PTXDIST

["Schenk, Gavin" <G.Schenk@eckelmann.de>]

Hi Michael,

> >
> > Thank you for the fast feedback, I will send a patch.
> >
> > Some Questions:
> > Using readlink is ok? (additional dependency rc-once -> readlink ) Is
> > there anything more lightweight?
> 
> Not that I know. Note: if you use 'readlink -f' then the busybox version
> has a option for this, so maybe:
> 
> 	select BUSYBOX_FEATURE_READLINK_FOLLOW	if BUSYBOX_READLINK
> 	select COREUTILS			if !BUSYBOX_READLINK
> 	select COREUTILS_READLINK		if !BUSYBOX_READLINK
> 
Ok, done.

> > Do we need this stuff configurable?
> 
> No. But I think we should have a sanity check. To avoid getting stuck in
> the system-update.target: A service that is part of system-update.target
> and starts the rescue target. rc-once.service and your service should
> both be sorted 'Before' that service. If no other service starts a
> different target we automatically fall into the rescue target.
> 
Is "FailureAction=reboot" or "FailureAction=rescue.target" in service file sufficient here?

I am not happy with my implementation today :-(. The main reason is, it does not cover my usecase where I want to do something:
   * Once at first boot
   * With UI on tty
   * Without conflicting rc-once

For this usecase it seems to be enough to add a service to system-update.target.wants with "After=rc-once.service". This is not flawless, because the system continues booting after rc-once is done e.g. getty.target. It seems to be related to "systemctl daemon-reexec" in systemd-rc-once I am not sure. The handling of bbinit beside systemd and managing write protection in this scripts scares me. I am afraid to break stuff when doing changes here.

I reverted my last commit where I added some recommendations of freedesktop.org:
   * Requires=sysinit.target
   * After=sysinit.target

The result was a broken system. I reverted this to your implementation
   * After=local-fs.target
   * Requires=local-fs.target
   * Before=system-update-cleanup.service
   * After=system-update.target

I will send my three small patches after this mail. It adds a bugfix (etc/rc-once.d -> /etc/rc-once.d) and the readlink check. I moved the deletion of /system-update into run_rc_once function. Not sure if you like this, I followed recommendation 2.

Best regards
Gavin Schenk


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