[biorach]

> Docker took off because there is no Linux. There are 50 different slightly incompatible OSes. So the best way to distribute software is to basically tar up the entire filesystem and distribute that. Dependency management has failed because there’s just too much sprawl.

That's not an accurate description of the main motivation for Docker. It's a nice secondary benefit, sure.

[api]

What is it then? It’s not a good security isolation tool. It’s not great at resource use isolation. Containers are bulkier than packages.

[bisby]

To some degree "there can be a ton of different versions of things" only applies to core OS packages. You mention Mac. but what version of python ships with macOS? What if I need a version other than what ships by default?

At a certain point you need to start defining the environment regardless of OS, and docker works as a tool that handles environment definition for literally any program (same thing works for ruby, java, python, etc). It handles more complex environment definition than packages, but is lighter than a VM. It's a middle ground, which is a great compromise for some cases and not for others.

Varying use cases and lots of flexibility is also the reason why linux is never going to just standardize the ecosystem and say "ok, there is only 1 openSSL package now." Some people see the ability to have a version of linux that is completely bonkers in versioning as a strength, akin to how some places have old windows 95 computers they still run because newer versions don't work properly. On linux, you could have old 1995 packages from a specific app, but the rest modern secure packages.

[xorcist]

It used to be completely free hosting, that's one thing that was great about it. Same thing made Sourceforge so completely dominant that it took many years for projects to move off it even after more suitable alternatives were made available.

But the main use case was probably convenience. It's a very quick way for Mac and Windows users to get a small Linux VM up and running, and utilize the copious amount of software written for it.

These days it's mostly standard, for better or worse. There are a handful vendor independent ways to distribute software but this works with most cloud vendors. Is it good? Probably not, but few industry standards are.

[byteknight]

Not to be contradictory but my understanding was, that absolutely is the main motivation.

It was to solve the age old "it runs on my machine".

Open to being wrong but when docker hit the scene I remember that being touted left and right.