Context: I am planning to switch to Docker for my localhost development environment. I have my localhost development-enviroment setup on a Mac with MAMP (lot of different vhosts), composer, git etcetera.
Question: Is it possible to have a docker based environment and my old environment next to each other, so I could start trying out one project in docker but in the mean time run my current project in the old stack? Because I have like 20+ projects running and no time to rebuild everyting, or even worse, mess up my production sites and projects....
Yes, you can run the Docker based environment alongside your old environment. The container technology allows to isolate all required dependencies for each project in a container image.
You only have to be careful with the port mapping, i.e. the ports which are already used by MAMP must not be used for mapping.