I have experienced that my iris server is gone due to upgrading the docker version when I have built IRIS server on docker container.
Based on this experience, I'd like to show you how to make a backup for the IRIS server before upgrading platform or docker, and the procedure for rebuilding the IRIS in a new environment.
###IRIS server backup procedure
When you have finished building for the IRIS server, you need to make a backup.
I recommend you that you make a backup before upgrading if you have classes,routines and globals that you want to take over when you rebuild your environment.