Make nsenter in reboot command optional about kured

[ckotzbauer]

But this only would work, if you can use binaries which are already inside the kured-image right? So maybe you use a custom-image?

[bh185140]

But this only would work, if you can use binaries which are already inside the kured-image right? So maybe you use a custom-image?

Yes, for the use cases I've listed

• systemd shutdown through signal can be done with /bin/kill already in the image
• #868 can be done with /bin/touch also already in the image on a mounted volume

I think it should be fairly small change that won't break any thing. Mainly need it for the reduced privileges as I can't use the new reboot signal methods since I need to run a small shell script in the command before hand.

[bh185140]

Main driver for this is mostly I needed a mechanism to trigger shutdowns as well as reboot. I could open up a separate issue for it I suppose, not sure if there would be enough interest in supporting shutdown on a reboot daemon. Though this could be a smaller change to go in.

[ckotzbauer]

Thanks for the explanations. Yes, both binaries are already present. For the path-based method we could just create a file with go-code at a configurable, mounted location. Shutdowns are not directly in scope of kured, I think.

[bh185140]

Happy to open up a PR for this if you think this change could go into Kured.
I see currently nsenter is done with /usr/bin/nsenter", fmt.Sprintf("-m/proc/%d/ns/mnt", pid), "-- where the pid is a constant 1. Can possibly replace it with a default argument --reboot-command-prefix="/usr/bin/nsenter -m/proc/1/ns/mnt --". Alternatively just make it boolean parameter on where or not we add nsenter.
What do you think?

[bh185140]

Raised a PR here if interested https://github.com/kubereboot/kured/pull/899/files

// PID set to 1, until we have a better discovery mechanism.

Saw this comment while making this. Could be another use case to support changing the PID as a configuration for rancher.