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WTF is a container?

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Re: WTF is a container?

#11

Post by chewchew »

dkarapetyan wrote: post #8

> The promise behind software containers is essentially the same. Instead of shipping around a full operating system and your software (and maybe the software that your software depends on), you simply pack your code and its dependencies into a container that can then run anywhere — and because they are usually pretty small, you can pack lots of containers onto a single computer. Already got it wrong. Current contain…

It's up to you to make your containers bloated or keep them slim. You can use the alpine versions of the official Dockerhub images. Python on Alpine is 30 MB (vs 267 MB for the debian one). https://hub.docker.com/r/library/python/tags/

You can create containers that are just a few MB with compiled languages like Go (5 MB). https://www.iron.io/microcontainers-tiny-portable-containers...

From the article: "Rather than starting with everything but the kitchen sink, start with the bare minimum and add dependencies on an as needed basis."

Re: WTF is a container?

#12

Post by chii »

stass wrote: post #7
simula67 wrote: post #3

Putting a little bit more thought into naming things can help newcomers understand these concepts more easily. The word container is too generic, why not call it an 'application jail' or a 'virtual operating system' ? Another word that is over used in our field is 'context'.

They were called "jails" long before "containers" became a thing on HN. Somehow "jails" didn't stick, so I'd assume it was even more confusing for newcomers.

Jail had no marketing hook. It's a very negative word. I'd guess that's Probably the major reason.

Re: WTF is a container?

#13

Post by disposablezero »

Weak virtualization often lacking security, resource metering/prioritizing/quotas. Hurray, zombie Docker instances needs a whole VM reboot yet again, still not fixed in several years. But look how fast I can deploy millions of containers without SELinux, monitoring, HIDS, SDN, billing, live migration, backup/restore/DR/data lifecycling and all the other things we just pretend to ignore when throwing away sensible production VMs on Type 1 hypervisors devopsec.

Re: WTF is a container?

#14

Post by kpil »

fenomas wrote: post #10

I'm only a beginner, but the analogy that makes sense to me is that containers do for app deployment what npm does for Javascript development. That is, the magical part isn't that Docker simulates an operating system and so on - the magic is that it allows a chunk of logic to precisely declare its dependencies - including on other pieces of logic which declare their own dependencies - and then Docker knows how to (in…

Not really - Linux package management systems do exactly that.

The magic - if there is any - is to combine it all together; separation, discovery, relatively easy packaging and dependencies.

Re: WTF is a container?

#15

Post by stephenr »

chewchew wrote: post #11
dkarapetyan wrote: post #8

> The promise behind software containers is essentially the same. Instead of shipping around a full operating system and your software (and maybe the software that your software depends on), you simply pack your code and its dependencies into a container that can then run anywhere — and because they are usually pretty small, you can pack lots of containers onto a single computer. Already got it wrong. Current contain…

It's up to you to make your containers bloated or keep them slim. You can use the alpine versions of the official Dockerhub images. Python on Alpine is 30 MB (vs 267 MB for the debian one). https://hub.docker.com/r/library/python/tags/ You can create containers that are just a few MB with compiled languages like Go (5 MB). https://www.iron.io/microcontainers-tiny-portable-containers... From the article: "Rather than…

If your app is a compiled go binary (so, it runs anywhere) why do you need a container?

The whole point of containerisation is to group installed dependencies (as opposed to installable dependencies like with a regular deb or rpm package) and configuration into a 'black box'.

If your binary is already a single-file distribution, why lump it in with the crapfest that is docker?

Re: WTF is a container?

#18

Post by hvidgaard »

dancek wrote: post #5

I agree that containers (both for shipping and servers) are a great idea. And because I'm tired of always configuring servers, I decided to give it a try some time ago. I wrapped my IRC client (weechat + glowing-bear) in a Docker container. Oh, not a container though, because I also needed https, which meant I needed either a mechanism to build and update letsencrypt certs in the weird format that weechat expects, or…

I wanted to write about my experience with containers. It mimics yours. The idea of a container is beautiful and elegant. The execution, not so much. I'm more or less convinced that to reduce this complexity, we need a limited scope ecosystem. Microsofts .Net would probably be a good place to start, but MS, being enterprise, have a habit of turning things into a mess of configuration.

Re: WTF is a container?

#19

Post by hvidgaard »

disposablezero wrote: post #13

Weak virtualization often lacking security, resource metering/prioritizing/quotas. Hurray, zombie Docker instances needs a whole VM reboot yet again, still not fixed in several years. But look how fast I can deploy millions of containers without SELinux, monitoring, HIDS, SDN, billing, live migration, backup/restore/DR/data lifecycling and all the other things we just pretend to ignore when throwing away sensible pro…

The smart use of containers is using it to specify the deployment. You should use proper virtualization as the environment to deploy into. Because you use containers doesn't mean you throw all that away.

Re: WTF is a container?

#20

Post by hvidgaard »

bbcbasic wrote: post #2

I've read before on HN about 'don't use docker in production' can anyone elaborate on that for a newbie?

There is a lot of infrastructure around security and availability that isn't yet achiveable with off the shelf software. So ideally you use containers to define dependencies and deployment, and deploy into a proper environment.
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