Docker is much easier than it seems, imagine a single app with all it’s dependencies all the way down to the os level being all wrapped up in a virtual filesystem so it can’t see anything else. Only the kernel is shared.

So if “Awesome Webapp Jeroboam” needs a different version of python than you have installed and and old version of ffmpeg for some utility it needs, along with the apache webserver where you prefer nginx, no problem, all that mess gets wrappped up in a container and you don’t have to worry about it.

To understand it you’ll need to know roughly what an OS is. Very roughly speaking an OS provides a program with a way to access files, connect to the internet and launch other programs.

What docker does is make something a bit like a ‘virtual’ OS with its own filesystem, network and task manager, and then start running programs in it (which then may launch other programs).

Since you’re not making a VM which must simulate all of the hardware, this is a lot cheaper. However since a docker container gets its own filesystem, network etc. it can do whatever it wants without any other programs getting in the way.

Among other things docker containers make installation a lot easier since a program will only ever see its own files (unless you explicitly add your own files to the docker container). To a large extent you also don’t need to worry about installing any prerequisites, since those can just be put into the container.

Making a docker container is a bit (a lot) like installing a fresh OS, just putting the stuff you need in it and then copying the whole OS whenever you want to run the thing again. Except it’s been optimized such that it takes about as much effort as launching a program, as opposed to a VM which needs dedicated resources and are generally slower than the machine that hosts them.

The important concepts aren’t that complicated.

Instead of nesting a computer (VM’s) the operating system makes the program think it’s on its own dedicated computer (isolated file system space, cpu, and memory shares). A Dockerfile is just a basic script to construct one of these computers by commands and files.

The real reason people get excited is because they can ship a Docker “image”. It’s a layered filesystem which really is just like saying there’s a system tracking who puts what files in what place and so it’s easier to just send the whole setup to someone then try to document how you should set all that stuff up to run their software.

This is “dummier” proof than the pre-existing convention of just using a package manager to do this for you.

Use chatgpt to help you keep going, it’s very helpful

edit: Thought I’d expand on this more. Treat ChatGPT like a fellow engineer who never gets annoyed at answering your questions, and will never tell you that you’re dumb (haha). Tell it what yo’ure trying to do, copy paste your commands into it, copy paste the error messages if you have any. Literally, inundate it with questions and info and it’ll help you understand what you’re doing and help you unblock yourself. It’s a great tool.