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What we collectively refer to as "containers" and software like Docker are just tools that take advantage of various facilities provided by the OS which allow one to isolate/restrict various resources like CPU, memory, network, visibility of other processes, filesystem access, fs layering and namespacing, provide traffic shaping, etc. These isolation features go back a really long time in various OS's, but only in the last few years have they seen mass adoption, which, alas is running a bit ahead of any effort to make it a formal standard or anything even close to that. And so the way you would create a "container" on Linux is very different from the way you'd do that on FreeBSD or Solaris or Windows. Docker was one of the first pieces of software to facilitate that on Linux (where it was and still is far from trivial), along with the whole docker image dockerhub ecosystem, etc. But ultimately what Docker does amounts to the right commands (or system calls) done, and you can have the same effect without Docker (there's even a nice Docker talk on youtube somewhere that shows how to do what Docker does without it from the command line). IMHO in the developer community at large few people care to understand the operating system intimately, and even fewer people know stuff like cgroups or the tc command on Linux, and that's primarily why Docker is so popular - you don't need to know any of it. I think it'd be nice if people stopped using "Docker" and "container" interchangeably, and if a set of tools emerged which would be more part of the OS distribution and less a separate concept/brand/company/whatever and was more or less uniform across, at least the Un*x-like OSs. |