How To: Identify If An App Update Ships With A New Docker Container

How to identify if an app update ships with a new Docker container.


In order to plan downtimes it is helpful to be able to estimate the length for the update procedure. Updates shipping a new Docker container will take much more time to finish.

Step 1

Identify your current app version by

root@ucs:~# univention-app info
UCS: 4.4-0 errata59
Installed: dhcp-server=12.0 samba4=4.10 horde=5.2.17-2
Upgradable: horde

You are currently running horde 5.2.17-2 which is upgradeable to a newer version.

Step 2

Update appcenter information
univention-app update

Step 3

List version and Docker information. The information is kept in the *.ini file of every app which is stored under /var/cache/univention-appcenter/ You can display these information as shown below. In this example you will notice from Horde version 5.2.17-2 to 5.2.17-3 the same DockerImage applies, so this update will only be a smal update as it does not re-deploy the Docker container.

root@ucs:~# cd /var/cache/univention-appcenter/
root@ucs:~# find . -name "horde*.ini" -exec grep -HE "^Version|DockerImage" {} \; | sort
./horde_20180426183924.ini:DockerImage =
./horde_20180426183924.ini:Version = 5.2.17-1
./horde_20180621115801.ini:DockerImage =
./horde_20180621115801.ini:Version = 5.2.17-2
./horde_20190403131236.ini:DockerImage =
./horde_20190403131236.ini:Version = 5.2.17-3