udev doesn't pick up volumes properly

[Dave Halter]

[Only happens on Ubuntu, not other OS's, like Debian]

When we are attaching a volume to a running Ubuntu server (using kvm/libvirt), most of the time the udev rules are not properly triggered. In the end the volume will most of the time not be available in `/dev/disk/by-id/virtio-<ID_SERIAL>`. Sometimes it works though (10%/20%?).

The reason for this is that udev somehow doesn't pick it up when the volume is attached. It looks like a timing issue. Just looking at `/sys/devices/pci0000:00/0000:00:05.0/virtio2/block/vdb/serial` makes it clear that it's there. However `udevadm info /dev/vdb` returns without the `ID_SERIAL` key. Only a `udevadm trigger` leads to a correct entry of `ID_SERIAL` and also fixes `/dev/disk/by-id`.

We are a small cloud provider (cloudscale.ch). We have tested this on Ubuntu (16.04/18.04), Debian 9, CentOS, CoreOS. We haven't tested this extensively, but it sure looks like it's only happening on Ubuntu. . We never had any issues reported on other OS's about this.

I tried looking at the differences of Debian and Ubuntu udev packages, but couldn't figure out what might be responsible for this behavior.

If someone needs an account for our control panel to reproduce this, please contact me, I'm happy to give you the resources to debug this.

[Nick Rosbrook (enr0n)]

Is this issue still relevant?

[Launchpad Janitor (janitor)]

[Expired for systemd (Ubuntu) because there has been no activity for 60 days.]