Comment 21 for bug 1811724

I encountered something very similar to this issue (maybe even this issue?) when my docker containers could not start (using snap on Ubuntu 20.04.3 LTS under VirtualBox with a Windows 10 host). Similar to others, `sudo apt install libblockdev-mdraid2` seems to have fixed it.

In case these log lines are useful context, they came from `sudo grep fail /var/log/syslog` (just trying to filter out some of the noise and I suspect that the devmapper/containerd/cni bits are not directly related):

Nov 4 05:22:48 docker kernel: [ 0.305507] acpi PNP0A03:00: fail to add MMCONFIG information, can't access extended PCI configuration space under this bridge.
Nov 4 05:22:48 docker systemd[1]: Starting GRUB failed boot detection...
Nov 4 05:22:48 docker systemd[1]: Finished GRUB failed boot detection.
Nov 4 05:22:48 docker udisksd[731]: failed to load module mdraid: libbd_mdraid.so.2: cannot open shared object file: No such file or directory
Nov 4 05:22:48 docker containerd[733]: time="2021-11-04T05:22:48.627329367Z" level=warning msg="failed to load plugin io.containerd.snapshotter.v1.devmapper" error="devmapper not configured"
Nov 4 05:22:48 docker containerd[733]: time="2021-11-04T05:22:48.635107136Z" level=error msg="failed to load cni during init, please check CRI plugin status before setting up network for pods" error="cni config load failed: no network config found in /etc/cni/net.d: cni plugin not initialized: failed to load cni config"
Nov 4 05:22:49 docker docker.dockerd[719]: snap-update-ns failed with code 1