Comment 0 for bug 1666573

In the open-iscsi test we boot a read-only root iscsi target, using
overlayroot.

Transiently this operation fails, ultimately leading to emergency shell.
Since this occurs in automated test, there is no access to that console
(it is being logged to a file).

The open iscsi test that triggers this is described at [1], including how
to run it.

Most recently, the open-iscsi version 2.0.873+git0.3b4b4500-14ubuntu17 has
run both successfully and failed when running for trigger cloud-utils and
systemd [2]

I am attaching a tarball with logs and artifacts from the autopackage
test runs here for posterity.

In the failure case we see evidence of failure at
  [ 52.729092] systemd[1]: media-root\x2dro.mount: Found ordering cycle on media-root\x2dro.mount/start
  [ 52.730938] systemd[1]: media-root\x2dro.mount: Found dependency on -.mount/start
  [ 52.735138] systemd[1]: media-root\x2dro.mount: Found dependency on media-root\x2dro.mount/start
  [ 52.739910] systemd[1]: Unable to break cycle
  [ 52.744992] systemd[1]: Requested transaction contains an unfixable cyclic ordering dependency: Resource deadlock avoided

And then it all goes sour later with:
  [ TIME ] Timed out waiting for device dev-disk-by\x2dlabel-UEFI.device.
  [DEPEND] Dependency failed for /boot/efi.
  [DEPEND] Dependency failed for Local File Systems.
  [ TIME ] Timed out waiting for device VIRTUAL-DISK cloudimg-rootfs.

for reference, the image's fstab is:
  LABEL=cloudimg-rootfs / ext4 defaults 0 0
  LABEL=UEFI /boot/efi vfat defaults 0 0

but /etc/fstab is updated by overlayroot in the initramfs, and as such
contains the following:
  #
  # This fstab is in an overlay. The real one can be found at
  # /media/root-ro/etc/fstab
  # The original entry for '/' and other mounts have been updated to be placed
  # under /media/root-ro.
  # To permanently modify this (or any other file), you should change-root into
  # a writable view of the underlying filesystem using:
  # sudo overlayroot-chroot
  #
  LABEL=cloudimg-rootfs /media/root-ro/ ext4 ro,defaults 0 0
  /media/root-ro/ / overlay lowerdir=/media/root-ro/,upperdir=/media/root-rw/overlay/,workdir=/media/root-rw/overlay-workdir/_ 0 0
  LABEL=UEFI /boot/efi vfat defaults 0 0 # overlayroot:fs-unsupported

--
[1] https://git.launchpad.net/~usd-import-team/ubuntu/+source/open-iscsi/tree/debian/tests/README-boot-test.md?h=ubuntu/devel
[2] http://autopkgtest.ubuntu.com/packages/o/open-iscsi/zesty/amd64

ProblemType: Bug
DistroRelease: Ubuntu 17.04
Package: open-iscsi 2.0.873+git0.3b4b4500-14ubuntu17
ProcVersionSignature: User Name 4.9.0-15.16-generic 4.9.5
Uname: Linux 4.9.0-15-generic x86_64
ApportVersion: 2.20.4-0ubuntu2
Architecture: amd64
Date: Tue Feb 21 15:50:58 2017
ProcEnviron:
 TERM=xterm-256color
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=en_US.UTF-8
 SHELL=/bin/bash
SourcePackage: open-iscsi
UpgradeStatus: No upgrade log present (probably fresh install)
modified.conffile..etc.iscsi.iscsid.conf: [inaccessible: [Errno 13] Permission denied: '/etc/iscsi/iscsid.conf']