I recently found an answer that I gave someone to a Facebook chat question in ~2016-2017, and was amazed at how “technically right” I was (i.e. totally wrong for the career question that I was answering).
I just wanted to post this to show that I am often too technologically focused, and that this can often get in the way of getting hired and getting things done the way everyone else is doing them. On the flipside, my heart is in the right place and this approach certainly wouldn’t have HURT the person I was giving advice to.
Here it is!
Yeah, I should make some docker vids! So, LXC is the original Linux-native implementation of containers. There was an implementation before, called OpenVZ, but that relied on a patched Linux kernel and I don’t think it’s used much anymore.
The mainline kernel itself exposes the “ingredients” for containers (user/process namespacing, cgroups, etc.) and LXC was one of the original implementations of ‘containers’ using these native building blocks.
Docker was originally a wrapper around LXC, but has now actually created their own implementation of the container back-end (using the same exposed ‘ingredients’ from the Linux kernel that LXC uses).
LXC (and now LXD) is under-hyped, solid, and a bit more intuitive for learning (more like FreeBSD Jails, less hype/magic than Docker). I think it’s good to learn LXC or FreeBSD jails before jumping into Docker.
All the concepts from LXC are totally applicable to Docker as well.
Docker, as a software product, layers some extra tools on top of this basic ‘containerization’ tech: they have their docker ‘hubs’ — pre-built application containers. They have extra networking stuff on top of what you’d get with LXC. They have something that looks like very basic container linking/service discovery. They have enormous amounts of hype, which can help you get a high-paying job (seriously. It’s worth learning just for that.)
I’m torn, because I’ve used Docker since before it was an open-source product (it used to be a paid thing called DotCloud), and have hated it for almost the entire time. It’s a complex, unstable, and questionably architected piece of software. It’s also incredibly overhyped and misused.
BUT: Docker has some great ideas in it, and is absolutely worth learning for your career. As a technology, it leaves a lot to be desired.
I’d love to hear what you think of Docker after getting comfortable with LXC. LXC will teach you the concepts that underlie all of this containerization stuff, and Docker adds some new features (and new headaches) onto that.
Let me know what you think, if/when you start your Docker journey!