After turning ann CallIns and providing env variables it worked!

There are a few more, the whole set:

## Embedded Python environment

ENV IRISUSERNAME "_SYSTEM"

ENV IRISPASSWORD "SYS"

ENV IRISNAMESPACE "USER"

ENV PYTHON_PATH=/usr/irissys/bin/

ENV PATH "/usr/irissys/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/home/irisowner/bin"

@Guillaume Rongier , correct me if I'm wrong (tooked from your code).

We need a oneliner or zpm to start callins ) It becomes important!

Docker gives you the freedom of IRIS version during development: you can switch to ANY IRIS version just by changing one line code in a Dockerfile. E.g. here the lowest before FROM $IMAGE is the one that will be used to work with your solution:

ARG IMAGE=intersystemsdc/irishealth-community:2020.3.0.200.0-zpm

ARG IMAGE=intersystemsdc/iris-community:2020.4.0.547.0-zpm

ARG IMAGE=containers.intersystems.com/intersystems/iris:2021.1.0.215.0

ARG IMAGE=intersystemsdc/iris-community

ARG IMAGE=intersystemsdc/irishealth-community

FROM $IMAGE