On trusty systems (at least), walinuxagent ships the udev rules to produce the devices that cloud-init expects to find. So that isn't the source of this bug.
Instead, the problem is that the Azure data source defaults to using /dev/sdb for ephemeral0 ('disk_aliases': {'ephemeral0': '/dev/sdb'} at [0]). Iff we detect a _fabric-formatted_ (i.e. NTFS) ephemeral disk, then the data source updates this default to instead point at that ephemeral disk (which will, correctly, be /dev/disk/azure/...). This happens fine on every first boot, but on subsequent boots, we don't find a fabric-formatted ephemeral disk (because we reformatted it on first boot), so we don't update the default, so we end up rewriting the mounts to point at /dev/sdb. (I'll give fixing this some thought, and then comment again with suggestions.) [0] https://git.launchpad.net/cloud-init/tree/cloudinit/sources/DataSourceAzure.py#n57 -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1603222 Title: Azure: incorrect entry in fstab for ephemeral disk To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/cloud-init/+bug/1603222/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs