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Ask HN: How do you use Docker in production?

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Re: Ask HN: How do you use Docker in production?

#91

Post by jjd1103 »

cpt1138 wrote: post #82
jjd1103 wrote: post #39

Earlier quoted context omitted.

Docker also enforces immutability. With a VM there's always the temptation to manually fix any issue that arises, and if you don't have some bulletproof way to document that then you'll have issues when you go to recreate the environment on a new machine. Docker kind of forces you to solve the original problem via the dockerfile, which is what will spawn images for any future installs anyway.

Could you explain this more? I think my confusions stems from where the config comes from. Regardless of whether I have a bit-for-bit image or a vm created from a bunch of script commands, the immutability disappears when I apply the config. So for my example If I have a role that specifies one instance of a a galera server. I have to config each one with the other servers in the pool. And each config will be depende…

To your first question: for me it's a on-paper vs reality difference. On paper you're exactly right re "vm created from a bunch of script commands" will end in the same state.

The reality is that once the VM is built there is the temptation/opportunity to make ad-hoc changes for any variety of reasons. Those ad-hoc changes sometimes make it back into the official build process, but sometimes they get forgotten in the heat of the moment. With docker you can't do this...to make the necessary change you are also changing the official build process. No opportunity for the two to deviate.

Second question: Yes, that is my understanding (though not a use case I have atm).

Re: Ask HN: How do you use Docker in production?

#92

Post by rficcaglia »

teacup50 wrote: post #85

I honestly find it really depressing to see all these folks taking code and applications that would otherwise be entirely portable, and rebuilding their entire deployment and development environment around a hard dependency on Linux. If Docker becomes sufficiently popular, it's going to put HUGE nails in the coffin of portability and the vibrancy of the UNIX ecosystem.

It is not a code portability issue - it is a configuration and environment and dependency volatility issue. Everyone can use cross compilable C and still have deploy and lifecycle headaches.

Re: Ask HN: How do you use Docker in production?

#93

Post by indygreg2 »

seppalala wrote: post #59
nextos wrote: post #44

Earlier quoted context omitted.

Very interesting. I'm curious, have you considered nixos?

Yes, very much so. In fact, our goal is to have NixOS based containers. Right now, we're using Debian as the base image, and there's /no/ guarantee that the versions of software installed are consistent (since Docker caches based on the line in a Dockerfile, rather than what's actually installed). With Nix, we can have version guarantees in all of our Docker images--including the cached images.

I blogged about this the other day and would love to hear about your experience!

http://gregoryszorc.com/blog/2014/10/13/deterministic-and-mi...

Re: Ask HN: How do you use Docker in production?

#94

Post by rckclmbr »

We're been using Docker and coreos+fleet for our production environment at GaiaGPS for a few months now, and have been very impressed. We use quay.io for building our repositories, triggered by a github commit.

I agree with what others have said, and for us, the biggest benefit we see is keeping our production environment up to date, and stable. We're a small shop, and want to waste as little time as possible maintaining our production environment. We were able to go from 1 host (that occasionally went down -- and downtime for every deploy) to a 3-node coreos cluster fairly easily. We can also scale up, or even recreate the cluster, very easily.

Re: Ask HN: How do you use Docker in production?

#95

Post by aaron42net »

evandev wrote: post #90
aaron42net wrote: post #58

We're moving all of production in EC2 from an old CentOS 5 image managed by capistrano to CoreOS, with fleet deploying images built by the docker.io build service and private repo. I love it. Every week, we rebuild our base image starting with the latest debian:stable image, apply updates, and then our apps are built off of the latest base image. So distro security updates are automatically included with our next dep…

The biggest problem I have overall is pushing new code. When you push new code to git, do you then stop a container and restart it to get a new container working? (Assuming you do something like git clone in the Dockerfile)

I grant the docker.io build and private repository service access to my github repo, drop a Dockerfile at the root of my git repo, and the build server does the checkout outside of the Dockerfile and then executes the Dockerfile. I then use a github webhook to trigger a build when there's a new checkin to the master or qa branches. If the dockerfile completes successfully (based on exit status codes), it then spits out new docker images tagged with either "master" or "qa".

My fleet unit does a docker pull before it starts the container. So I just stop and start an individual unit to get it to run a new version.

Though fleet has a concept of global units (that run on all available machines), there's no way to do a rolling restart with them yet. Instead, I use unit templates to launch multiple instances of the same unit, and then stop and start each instance individually, and wait for it to respond before continuing to the next one. I intend to catch a webhook from the build server and do this automatically, but haven't written this yet.

Re: Ask HN: How do you use Docker in production?

#97

Post by BrianEatWorld »

We have a stateless worker process that previously required a separate EC2 instance for each worker. Even using small instances, this meant a pretty cumbersome fleet in AWS with lags for spin up and excess costs due to workers that were brought online and finished their jobs well before the use hour was complete.

Using Docker, we can have several of these workers on a single box with near instantaneous spin up. This means that we are able to use fewer, larger instances instead of several small ones. In turn, this makes the fleet easier to manage, quicker to scale and less costly because we aren't over paying for large portions of AWS hours that go under utilized.

I am not entirely sure that Docker was a necessity in building this as I sort of inherited the technology. I originally was pushing for a switch to pure LXC, which would have fit the build system that was in place better. However, given the fervour over Docker there is a lot of information out on the web and so changing the build and deployment systems has been relatively easy and quick. I bring this up because I think some tasks are better suited to pure LXC, but people seem to be defaulting to Docker due to its popularity.

Re: Ask HN: How do you use Docker in production?

#98

Post by piva00 »

We're using Docker to solve these kinds of problems:

- Running Jenkins slaves for some acceptance/integration tests that runs in the browser, previously we had to configure multiple chromedrivers to spin up on different ports or be stuck running 1 test per machine. Now we have 6 machines (down from 9) which runs 6 slaves each, so we can parallelize our tests as 36 tests run concurrently. That has significantly improved our deployment time (as these tests are necessary to do a deployment) while reducing costs.

- Migrating our infrastructure (around 70 instances) to AWS VPC, we had our machines running on EC2-Classic. While I had previously done some work automating most applications using Chef we have really managed to fully automate our machines with Docker, it was way easier than solving cookbook dependency and customization issues. We have a couple dozen Dockerfiles that fully explain how our systems run and what are the dependencies for each application.

And that is only in the last month and a half that I began using Docker, I was pretty skeptical before as it was touted almost as a silver bullet. And it comes close to that in many scenarios.

Re: Ask HN: How do you use Docker in production?

#99

Post by cpuguy83 »

seppalala wrote: post #59
nextos wrote: post #44

Earlier quoted context omitted.

Very interesting. I'm curious, have you considered nixos?

Yes, very much so. In fact, our goal is to have NixOS based containers. Right now, we're using Debian as the base image, and there's /no/ guarantee that the versions of software installed are consistent (since Docker caches based on the line in a Dockerfile, rather than what's actually installed). With Nix, we can have version guarantees in all of our Docker images--including the cached images.

Well sure there can be a guarantee.

`RUN apt-get install some_package=` If you want a newer version, update the Dockerfile with the version you want.

Re: Ask HN: How do you use Docker in production?

#100

Post by zwischenzug »

jjd1103 wrote: post #39
mattip wrote: post #16

Earlier quoted context omitted.

What value does Docker add if you are already running a VM? Are the laptops Linux, so Docker provides a lighter alternative to a full vm environment?

Docker also enforces immutability. With a VM there's always the temptation to manually fix any issue that arises, and if you don't have some bulletproof way to document that then you'll have issues when you go to recreate the environment on a new machine. Docker kind of forces you to solve the original problem via the dockerfile, which is what will spawn images for any future installs anyway.

Only true if you don't go to the network:

http://zwischenzugs.wordpress.com/2014/07/16/phoenix-deploym...

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