Docker.md improvements, requirements and troubleshooting

[polarbearing]

update docker.md with requirements and troubleshooting from last night's installation experience.
Trying to cover different host OS, while experience is from MacOS.

[matkoniecz]

You need sufficient disk space of several Gigabytes

Is it really worth mentioning? I think that it would be unusual to not have this amount of free space available

an environment that allows you to create a virtual machine

AFAIK it is mac-specific (from wikipedia - "Docker on macOS uses a Linux virtual machine to run the containers."). "virtualized environment" is true also for mac while virtual machine bit is not true for Linux and Windows where operating-system-level virtualization is used.

increase the Memory assigned in the Docker Preferences > Advanced > Adjust the computing resources.

It is tricky, as even existence of "Docker Preferences" menu is system-dependent.

[polarbearing]

Size - If you have a tower under your desk with several TB disks, you don't need to worry. My 2yo laptop has a 500 GB SSD which is pretty full, in particular with other virtual images around. I was spending the whole night observing the virtual machine growing like sour dough, and shuffling other stuff out. The problem was that I had no indication what size to expect in the end.

virtual machine - yes, reading further there is the Docker daemon, which might reside in a virtual machine depending on OS.

Preferences - might put that in brackets as examples.

[polarbearing]

Issues should be addressed.

[kocio-pl]

@matkoniecz What do you think about it now?

[kocio-pl]

@matkoniecz ping?

[kocio-pl]

Thanks! I have finally find the time to look myself and I find these remarks useful if I would ever use Docker on macOS or Windows. It also looks to me that all the requests have been resolved.