upgrade problem when using packages from security (docker.io and containerd)

[Daniel]

Starting from the following situation:

Ubuntu 20.04.3 LTS with up-to-date packages EXCEPT docker.io and containerd. Normal archive and security repositories enabled. The following happens on two individual systems:

$ apt-cache policy docker.io containerd
docker.io:
  Installed: 19.03.8-0ubuntu1
  Candidate: 20.10.7-0ubuntu1~20.04.1
  Version table:
     20.10.7-0ubuntu1~20.04.1 500
        500 http://ch.archive.ubuntu.com/ubuntu focal-updates/universe amd64 Packages
        500 http://security.ubuntu.com/ubuntu focal-security/universe amd64 Packages
 *** 19.03.8-0ubuntu1 500
        500 http://ch.archive.ubuntu.com/ubuntu focal/universe amd64 Packages
        100 /var/lib/dpkg/status
containerd:
  Installed: 1.3.3-0ubuntu2
  Candidate: 1.5.2-0ubuntu1~20.04.2
  Version table:
     1.5.2-0ubuntu1~20.04.2 500
        500 http://ch.archive.ubuntu.com/ubuntu focal-updates/main amd64 Packages
        500 http://security.ubuntu.com/ubuntu focal-security/main amd64 Packages
 *** 1.3.3-0ubuntu2 500
        500 http://ch.archive.ubuntu.com/ubuntu focal/main amd64 Packages
        100 /var/lib/dpkg/status

When I try to update, both packages have a new version, but neither of these succeed to update:

$ sudo apt-get dist-upgrade
Reading package lists... Done
Building dependency tree
Reading state information... Done
Calculating upgrade... Done
The following packages will be upgraded:
  containerd docker.io
2 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.
2 standard security updates
Need to get 0 B/69.8 MB of archives.
After this operation, 20.4 MB of additional disk space will be used.
Do you want to continue? [Y/n]
Preconfiguring packages ...
(Reading database ... 233087 files and directories currently installed.)
Preparing to unpack .../docker.io_20.10.7-0ubuntu1~20.04.1_amd64.deb ...
The aufs storage-driver is no longer supported.
Please ensure that none of your containers are
using the aufs storage driver, remove the directory
/var/lib/docker/aufs and try again.
dpkg: error processing archive /var/cache/apt/archives/docker.io_20.10.7-0ubuntu1~20.04.1_amd64.deb (--unpack):
 new docker.io package pre-installation script subprocess returned error exit status 1
dpkg: error while cleaning up:
 installed docker.io package post-installation script subprocess returned error exit status 1
Preparing to unpack .../containerd_1.5.2-0ubuntu1~20.04.2_amd64.deb ...
Unpacking containerd (1.5.2-0ubuntu1~20.04.2) over (1.3.3-0ubuntu2) ...
Errors were encountered while processing:
 /var/cache/apt/archives/docker.io_20.10.7-0ubuntu1~20.04.1_amd64.deb
E: Sub-process /usr/bin/dpkg returned an error code (1)

I can also try these packages individually, also with errors:

$ sudo apt-get install docker.io
$ sudo apt-get install containerd

As a work-around, I can reset to the last (non-security) version, and then set the two packages on hold:

$ sudo apt-get install docker.io=19.03.8-0ubuntu1 containerd=1.3.3-0ubuntu2
$ sudo apt-mark hold containerd docker.io

[Christophe Lyon (christophe-lyon)]

Looks related to https://bugs.launchpad.net/ubuntu/+source/docker.io/+bug/1939140