In the past few days when I ran apt manually on Labs instances, I noticed:
scfc@tools-services-01:~/src/tools-manifest$ sudo apt-get install python-mysql.connector Reading package lists... Done […] Setting up python-mysql.connector (1.1.6-1) ... N: Ignoring file '20auto-upgrades.ucf-dist' in directory '/etc/apt/apt.conf.d/' as it has an invalid filename extension scfc@tools-services-01:~/src/tools-manifest$
This file is apparently from December 2013:
scfc@tools-services-01:~/src/tools-manifest$ ls -l /etc/apt/apt.conf.d/20auto-upgrades.ucf-dist -rw-r--r-- 1 root root 80 Dec 6 2013 /etc/apt/apt.conf.d/20auto-upgrades.ucf-dist scfc@tools-services-01:~/src/tools-manifest$
and contains apt configuration:
scfc@tools-services-01:~/src/tools-manifest$ cat /etc/apt/apt.conf.d/20auto-upgrades.ucf-dist APT::Periodic::Update-Package-Lists "0"; APT::Periodic::Unattended-Upgrade "0"; scfc@tools-services-01:~/src/tools-manifest$
that a) is ignored due to the file name's extension and b) would contradict (IIUC) that Labs instances include apt::unattendedupgrades by default (except Beta-Cluster-Infrastructure).
My assumption is that the instance used to build the VM images was/is dirty, but previously only explicitly named files from /etc/apt/apt.conf.d were copied. After @hashar's change 30b782bf3004950297d50070ab3bcc5dfc18cc59 was merged and new images were built, now all of /etc/apt/apt.conf.d is copied, including the cruft.