apt-get upgrade hangs on Xenial

[Bob Jones]

Description: Ubuntu 16.04.1 LTS
Release: 16.04
apt 1.2.12 (amd64)
Supported modules:
*Ver: Standard .deb
*Pkg: Debian dpkg interface (Priority 30)
 Pkg: Debian APT solver interface (Priority -1000)
 S.L: 'deb' Debian binary tree
 S.L: 'deb-src' Debian source tree
 Idx: Debian Source Index
 Idx: Debian Package Index
 Idx: Debian Translation Index
 Idx: Debian dpkg status file
 Idx: Debian deb file
 Idx: Debian dsc file
 Idx: Debian control file
 Idx: EDSP scenario file

During an "apt-get upgrade" run today (2016-08-18), the process has been hanging for over an hour now ! It hangs at mdadm.conf as per below tail of output :

Processing triggers for systemd (229-4ubuntu7) ...
Processing triggers for ureadahead (0.100.0-19) ...
Processing triggers for man-db (2.7.5-1) ...
Processing triggers for dbus (1.10.6-1ubuntu3) ...
Processing triggers for libc-bin (2.23-0ubuntu3) ...
Processing triggers for initramfs-tools (0.122ubuntu8.1) ...
update-initramfs: Generating /boot/initrd.img-4.4.0-34-generic
W: mdadm: /etc/mdadm/mdadm.conf defines no arrays.
****it is hanging here, no further output****

[Bob Jones (r-a-n-d-o-m-d-e-v-4+ubuntu)]

I killed it and tried "sudo dpkg --configure -a", and the same thing repeats itself !

sudo dpkg --configure -a
Setting up zfs-doc (0.6.5.6-0ubuntu12) ...
Setting up libuutil1linux (0.6.5.6-0ubuntu12) ...
Setting up language-selector-common (0.165.4) ...
Setting up initramfs-tools (0.122ubuntu8.1) ...
update-initramfs: deferring update (trigger activated)
Setting up libnvpair1linux (0.6.5.6-0ubuntu12) ...
Setting up snapd (2.12+0.16.04) ...
Setting up libpq5:amd64 (9.5.4-1.pgdg16.04+1) ...
Setting up postgresql-doc-9.5 (9.5.4-1.pgdg16.04+1) ...
Setting up postgresql-client-9.5 (9.5.4-1.pgdg16.04+1) ...
Setting up postgresql-9.5 (9.5.4-1.pgdg16.04+1) ...
Setting up python3-software-properties (0.96.20.3) ...
Setting up linux-firmware (1.157.3) ...
Setting up libapparmor-perl (2.10.95-0ubuntu2.2) ...
Setting up python3-distupgrade (1:16.04.16) ...
Setting up software-properties-common (0.96.20.3) ...
Setting up libzpool2linux (0.6.5.6-0ubuntu12) ...
Setting up apparmor (2.10.95-0ubuntu2.2) ...
Installing new version of config file /etc/apparmor.d/abstractions/dbus-session-strict ...
update-rc.d: warning: start and stop actions are no longer supported; falling back to defaults
Skipping profile in /etc/apparmor.d/disable: usr.sbin.rsyslogd
Files /var/lib/dpkg/info/apparmor.md5sums and /var/lib/apparmor/profiles/.apparmor.md5sums differ
Setting up ubuntu-release-upgrader-core (1:16.04.16) ...
Setting up libzfs2linux (0.6.5.6-0ubuntu12) ...
Setting up postgresql-contrib-9.5 (9.5.4-1.pgdg16.04+1) ...
Setting up zfsutils-linux (0.6.5.6-0ubuntu12) ...
Installing new version of config file /etc/cron.d/zfsutils-linux ...
zfs-import-cache.service is a disabled or a static unit, not starting it.
zfs-import-scan.service is a disabled or a static unit, not starting it.
zfs-mount.service is a disabled or a static unit, not starting it.
Processing triggers for initramfs-tools (0.122ubuntu8.1) ...
update-initramfs: Generating /boot/initrd.img-4.4.0-34-generic
W: mdadm: /etc/mdadm/mdadm.conf defines no arrays.
****it is hanging here, no further output****

[Julian Andres Klode (juliank)]

Not sure where it's hanging, but not in apt.

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Egon (erijpkema)]

Encountered the same bug today. Resorted to killing the madm process.
```
pstree of apt at the time:
dpkg───initramfs-tools───update-initramf───mkinitramfs───mdadm───mkconf───mdadm
```
```
 sudo dpkg --configure -a
Setting up initramfs-tools (0.122ubuntu8.13) ...
update-initramfs: deferring update (trigger activated)
Processing triggers for initramfs-tools (0.122ubuntu8.13) ...
update-initramfs: Generating /boot/initrd.img-4.4.0-138-generic
W: mdadm: /etc/mdadm/mdadm.conf defines no arrays.
Terminated
W: mdadm: failed to auto-generate temporary mdadm.conf file.
```

[Paul White (paulw2u)]

Thank you for taking the time to report this bug and helping to make Ubuntu better. We are sorry that we do not always have the capacity to review all reported bugs in a timely manner.

Ubuntu 16.04 (xenial) reached end-of-standard-support on April 29, 2021.

I'm setting the status of this bug to 'Incomplete' as it's not seen any activity for some time. If this is still an issue when using a currently maintained release of Ubuntu then please let us know which one(s) otherwise this bug report can be left to expire in approximately 60 days time.

[Launchpad Janitor (janitor)]

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