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Docker at Spotify

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Re: Docker at Spotify

#11

Post by ermintrude »

They let devs ssh onto production boxes and do what they want?!?! "Things diverge pretty quickly" - I'm sure they do. That sounds like a recipe for disaster...

Docker looks promising but until there's a way to allocate maximum resources to a container I wouldn't use it in production. VMs are much slower to start but at least a runaway process on one won't affect other VMs on the same hardware.

Docker only lets you hint that only a certain number of cores should be used, so a bad process might monopolise the physical machine. Also until other tools (ansible, salt, chef, etc) help with provisioning you need to edit the dockerfile to change parameters (eg for settings that depend on your environment like smtp end points test vs prod, etc).

If these points are addressed I think it'll be awesome though.

Re: Docker at Spotify

#13

Post by danielbln »

ermintrude wrote: post #11

They let devs ssh onto production boxes and do what they want?!?! "Things diverge pretty quickly" - I'm sure they do. That sounds like a recipe for disaster... Docker looks promising but until there's a way to allocate maximum resources to a container I wouldn't use it in production. VMs are much slower to start but at least a runaway process on one won't affect other VMs on the same hardware. Docker only lets you hi…

Docker lets you restrict memory and cpu consumption on a per-container basis. Configuration like endpoints are usually fed into the container via environment variables, not by changing stuff around in the Dockerfile. This way you can use the same container in multiple environments.

Re: Docker at Spotify

#14

Post by ldng »

ermintrude wrote: post #11

They let devs ssh onto production boxes and do what they want?!?! "Things diverge pretty quickly" - I'm sure they do. That sounds like a recipe for disaster... Docker looks promising but until there's a way to allocate maximum resources to a container I wouldn't use it in production. VMs are much slower to start but at least a runaway process on one won't affect other VMs on the same hardware. Docker only lets you hi…

Aren't cgroups be more then a hitting ? Or do you mean that by default does not setup strict enough cgroups ?

Re: Docker at Spotify

#15

Post by casca »

allbutlost wrote: post #10
casca wrote: post #8

"* Please note Docker is currently under heavy developement. It should not be used in production (yet)." [1] [1] http://www.docker.io/learn_more/

This is addressed in the talk. It's a short talk, so may be worth listening to it to see how it was used.

Agreed, but I'd have thought that it was worth raising for those who are not familiar with where Docker is in the development cycle.

Re: Docker at Spotify

#16

Post by edwinnathaniel »

ermintrude wrote: post #11

They let devs ssh onto production boxes and do what they want?!?! "Things diverge pretty quickly" - I'm sure they do. That sounds like a recipe for disaster... Docker looks promising but until there's a way to allocate maximum resources to a container I wouldn't use it in production. VMs are much slower to start but at least a runaway process on one won't affect other VMs on the same hardware. Docker only lets you hi…

Take a look at packer.io

Re: Docker at Spotify

#17

Post by ermintrude »

edwinnathaniel wrote: post #16
ermintrude wrote: post #11

They let devs ssh onto production boxes and do what they want?!?! "Things diverge pretty quickly" - I'm sure they do. That sounds like a recipe for disaster... Docker looks promising but until there's a way to allocate maximum resources to a container I wouldn't use it in production. VMs are much slower to start but at least a runaway process on one won't affect other VMs on the same hardware. Docker only lets you hi…

Take a look at packer.io

Thanks. I had seen packer.io but then forgot about it.

I had another look at Docker in November and had issues installing what I needed via apt for some reason. It wasn't a drop-in replacement for VMs for several reasons (I wanted an alternative backend to provision with salt), but when it hits 1.0 I'll have a look again, if not before.

Re: Docker at Spotify

#18

Post by ermintrude »

ldng wrote: post #14
ermintrude wrote: post #11

They let devs ssh onto production boxes and do what they want?!?! "Things diverge pretty quickly" - I'm sure they do. That sounds like a recipe for disaster... Docker looks promising but until there's a way to allocate maximum resources to a container I wouldn't use it in production. VMs are much slower to start but at least a runaway process on one won't affect other VMs on the same hardware. Docker only lets you hi…

Aren't cgroups be more then a hitting ? Or do you mean that by default does not setup strict enough cgroups ?

It seems cpu.shares allow a proportional amount of CPU to be allocated, but LXC may use up to 100% of all idle CPUs. You can't specify a hard-limit of "only use 1GHz when I have a 2GHz CPU" apparently (according to here: http://comments.gmane.org/gmane.linux.kernel.containers.lxc....). So I guess that could mean that if the containers are using 100% of all CPUs, there wouldn't be resources left e.g. for monitoring on the host? Anyone got any experience with this?

Re: Docker at Spotify

#19

Post by [deleted] »

ermintrude wrote: post #18
ldng wrote: post #14

Earlier quoted context omitted.

Aren't cgroups be more then a hitting ? Or do you mean that by default does not setup strict enough cgroups ?

It seems cpu.shares allow a proportional amount of CPU to be allocated, but LXC may use up to 100% of all idle CPUs. You can't specify a hard-limit of "only use 1GHz when I have a 2GHz CPU" apparently (according to here: http://comments.gmane.org/gmane.linux.kernel.containers.lxc.... ). So I guess that could mean that if the containers are using 100% of all CPUs, there wouldn't be resources left e.g. for monitoring o…

[deleted]

Re: Docker at Spotify

#20

Post by edwinnathaniel »

ermintrude wrote: post #17
edwinnathaniel wrote: post #16

Earlier quoted context omitted.

Take a look at packer.io

Thanks. I had seen packer.io but then forgot about it. I had another look at Docker in November and had issues installing what I needed via apt for some reason. It wasn't a drop-in replacement for VMs for several reasons (I wanted an alternative backend to provision with salt), but when it hits 1.0 I'll have a look again, if not before.

Definitely it is not. You'd have to prepare the docker instance a little bit differently than you would for VM.

For example: Docker does not run upstart by default.

re: issues with installing via apt => Docker public registry provided a stock Ubuntu 12.04 with a lot of things stripped out including the /etc/apt/sources.list (it contains only 1 entry). You'd have to populate that sources.list with a Ubuntu/Debian that you already have.

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