[systemd-devel] Unset option in drop-in override

[Dominick C. Pastore]

On Wed, Jun 19, 2019, at 6:19 AM, Lennart Poettering wrote:
> On Di, 18.06.19 22:05, Dominick C. Pastore (dominickpastore at dcpx.org) wrote:
> 
> > Hello,
> >
> > I think this is an easy question but I can't find the answer
> > anywhere.
> 
> Which version of systemd are you using?

Version 232.

> > I'm having some trouble with a unit file drop-in overrride. I have a package that uses some options that are incompatible with the LXD container I'm running it in. Specifically, the following two options:
> >
> > [Service]
> > IOSchedulingClass=realtime
> > CPUSchedulingPolicy=rr
> >
> > So I used "systemd edit" to try and override these using the following:
> >
> > [Service]
> > IOSchedulingClass=
> > CPUSchedulingPolicy=
> >
> > The problem is, then I get the messages "Failed to parse IO
> > scheduling class, ignoring: " and "Failed to parse CPU scheduling
> > policy, ignoring: " in the journal.
> 
> In current versions (since 239) this should work fine. Please upgrade
> (or ask your distro to backport
> 617d253afad10ca9c7861eb3a2b381a8f95cf4ad.
> 
> You might be able to do the following though:
> 
>    IOSchedulingClass=be
>    CPUSchedulingPolicy=other
> 
> which are the default values. I didn't test that though, I am not sure
> if the kernel will let you set the parameters to the values already
> set without complaining.

Thanks, that's good to know. I'll give the default values a try first and switch to the backport if it still complains.

> Alternatively, just copy the unit file from /usr/lib to /etc, and
> comment the relevant lines. That way you override the whole file.

This is indeed what I am currently doing, but I'm concerned it will mask an update to the original unit file. I'll give the other suggestions a try.

Thanks for the advice.

Dominick