New functionality: Providing access to host's environmental variables

snapd
1

Last week, systemd checked in a change to provide read-only access to host’s environmental variables as some developers would benefit from changing their functionality based on those variables.
https://github.com/systemd/systemd/pull/15891#event-3527167929

Official interface update is here:
https://www.freedesktop.org/software/systemd/man/os-release.html

The logic is read-only mount of host os directories:
/etc/os-release -> /run/host/etc/os-release if it exists
/usr/lib/os-release -> /run/host/usr/lib/os-release

containerd seems to be moving in the same direction: https://github.com/containerd/containerd/issues/4286

Does that make sense for snapd to have that functionality? If so, I would like to contribute by implementing it in snapd. Disclaimer, I am new to open source contrition by I was able to successfully modify and build snapd.

Any recommendations on which would be the proper function that should have mounting code? Which function should ensure unmounting?

Thanks,
Denis

2

It sounds like the discussion has already started for snapd:RFE: common interface to expose host's os-release to container-like runtimes

"For snaps the non auto-connected interface system-observe already lets a snap access the host os-release under /var/lib/snapd/hostfs/etc/os-release or /var/lib/snapd/hostfs/usr/lib/os-release in the snap mount namespace.

If there is some consensus with container runtimes that this information should be exposed over environment variables a new interface could be added that enables that as well."

Does adding another mapping to have a standard across the industry make sense now since systemd is already doing it?
/etc/os-release -> /run/host/etc/os-release if it exists
/usr/lib/os-release -> /run/host/usr/lib/os-release