Comment 8 for bug 1676991

At least with the combination of MAAS and curtin below, /etc/fstab with bcache was written with UUID. So marking curtin as Fix Released. Looks like lp:curtin of revision 484 is included in SRU of xenial (xenial has revno 505 now).

$ apt policy maas python3-curtin
maas:
  Installed: 2.2.1-6078-g2a6d96e-0ubuntu1~16.04.1
  Candidate: 2.2.1-6078-g2a6d96e-0ubuntu1~16.04.1
  Version table:
 *** 2.2.1-6078-g2a6d96e-0ubuntu1~16.04.1 500
        500 http://ppa.launchpad.net/maas/stable/ubuntu xenial/main amd64 Packages
        500 http://ppa.launchpad.net/maas/stable/ubuntu xenial/main i386 Packages
        100 /var/lib/dpkg/status
     2.2.0+bzr6054-0ubuntu2~16.04.1 500
        500 http://archive.ubuntu.com/ubuntu xenial-updates/main amd64 Packages
        500 http://archive.ubuntu.com/ubuntu xenial-updates/main i386 Packages
     2.0.0~beta3+bzr4941-0ubuntu1 500
        500 http://archive.ubuntu.com/ubuntu xenial/main amd64 Packages
        500 http://archive.ubuntu.com/ubuntu xenial/main i386 Packages
python3-curtin:
  Installed: 0.1.0~bzr505-0ubuntu1~16.04.1
  Candidate: 0.1.0~bzr505-0ubuntu1~16.04.1
  Version table:
 *** 0.1.0~bzr505-0ubuntu1~16.04.1 500
        500 http://archive.ubuntu.com/ubuntu xenial-updates/main amd64 Packages
        500 http://archive.ubuntu.com/ubuntu xenial-updates/main i386 Packages
        100 /var/lib/dpkg/status
     0.1.0~bzr482-0ubuntu1~16.04.1 500
        500 http://ppa.launchpad.net/maas/stable/ubuntu xenial/main amd64 Packages
        500 http://ppa.launchpad.net/maas/stable/ubuntu xenial/main i386 Packages
     0.1.0~bzr365-0ubuntu1 500
        500 http://archive.ubuntu.com/ubuntu xenial/main amd64 Packages
        500 http://archive.ubuntu.com/ubuntu xenial/main i386 Packages

FWIW, bcache layout was specified by the following command:

$ maas "$PROFILE" machine set-storage-layout "$system_id" \
        storage_layout=bcache \
        cache_no_part=true \
        cache_mode=writeback