Request: system-files declaration + auto-connect for snap-openstack-hypervisor (mdevctl-config plug)

Hi store team,

We’ve added a new `system-files` plug to the `snap-openstack-hypervisor` snap (published by Canonical) as part of adding s390x support. The revision is flagged for manual review because of it.

Plug definition:

plugs: 
  mdevctl-config: 
    interface: system-files
    read:
      - /etc/mdevctl.d

This is connected to the `libvirtd` app.

Justification:

snap-openstack-hypervisor packages the libvirt/nova-compute virtualization stack for OpenStack Sunbeam. On s390x, libvirt’s mediated-device (mdev) discovery reads the persistent mdevctl configuration directory at /etc/mdevctl.d to enumerate defined mediated devices. Without read access to this path, libvirtd cannot discover host-defined mdevs. The access is strictly read-only and scoped to the single /etc/mdevctl.d directory that mdevctl owns.

No existing interface covers this. libvirtd already plugs hardware-observe, mount-observe, system-observe, block-devices, kvm, and the custom microstack-support interface; none of these grant /etc/mdevctl.d. I confirmed the microstack-support definition in snapd contains no rules for /etc/mdevctl.d (or /etc generally).

Requests:

  1. Grant the snap declaration for the `mdevctl-config` system-files plug so the revision can pass review.
  2. Please also grant auto-connection for this plug. libvirtd runs as a confined system daemon and needs the access to function on fresh installs; requiring a manual `snap connect` would leave mdev discovery broken by default.

Snap: https://snapcraft.io/snap-openstack-hypervisor

PR: snap: fix s390x hypervisor snap packaging by MylesJP · Pull Request #202 · canonical/snap-openstack-hypervisor · GitHub

Thanks!

This request has not been added to the review queue. It should be placed in the appropriate store-requests subcategory using the subcategory template for classic-confinement, privileged-interfaces and aliases requests.