I don't think I'm interested in containers

April 20, 2015

Containers are all the rage in system administration right now, and I can certainly see the appeal. So it feels more than a bit heretical to admit that I'm not interested in them, ultimately because I don't think they're an easy fit for our environment.

What it comes down to is two things. The first is that I think containers really work best in a situation where the 'cattle' model of servers is a good fit. By contrast, our important machines are not cattle. With a few exceptions we have only one of each machine today, so in a container world we would just be turning those singular machines into singular containers. While there are some wins for containers I'm not convinced they're very big ones and there are certainly added complexities.

The second is that we are pretty big on using different physical machines to get fault independence. As far as we're concerned it's a feature that if physical machine X dies for whatever reason, we only lose a single service. We co-locate services only infrequently and reluctantly. This obviously eliminates one of the advantages of containers, which is that you can run multiple containers on a single piece of hardware. A world where we run a base OS plus a single container on most servers is kind of a more complicated world than we have now and it's not clear what it gets us.

I can sort of imagine a world where we become a container based environment (even with our present split of services) and I can see some advantages to it. But it's clear that it would take a lot of work to completely redo everything in our environment as a substrate of base OS servers and then a strata of ready to go containers deployed on top of them, and while we'd get some things out of such a switch I'm not convinced we'd get a lot.

(Such a switch would be more like a green field rebuild from total scratch; we'd probably want to throw away everything that we do now. This is just not feasible for us for various reasons, budget included.)

So the upshot of all of this is that while I think containers are interesting as a technical thing and I vaguely keep track of the whole area, I'm not actually interested in them and I have no plans to explore them, try them out, and so on. I feel oddly embarrassed by this for reasons beyond the comfortable scope of this entry, but there it is whether I like it or not.

(I was much more optimistic a few years ago, but back then I was just theorizing. Ever since then I've failed to find a problem around here where I thought 'yes, containers will make my life simpler here and I should advocate for them'. Even my one temptation due to annoyance was only a brief flirtation before sense set in.)

Written on 20 April 2015.
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Last modified: Mon Apr 20 23:57:51 2015
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