CODEWITHSUNDEEP
ruby-on-railsdeploymentdocker
Carlos Castellanos
Carlos Castellanos

Reputation: 2378

Linking containers together on production deploys

I want to migrate my current deploy to docker, it counts on a mongodb service, a redis service, a pg server and a rails app, I have created already a docker container for each but i have doubts when it comes to start and linking them. Under development I'm using fig but I think it was not meant to be used on production. In order to take my deployment to production level, what mechanism should I use to auto-start and link containers together? my deploy uses a single docker host that already runs Ubuntu so i can't use CoreOS.

Upvotes: 6

Views: 651

Answers (2)

Abel Muiño
Abel Muiño

Reputation: 7771

Linknig containers in production is a tricky thing. It will hardwire the IP addresses of the dependent containers so if you ever need to restart a container or launch a replacement (like upgrading the version of mongodb) your rails app will not work out of the box with the new container and its new IP address.

This other answer explains some available alternatives to linking.

Regarding starting the containers, you can use any deployment tool to run the required docker commands (Capistrano can easily do that). After that, docker will restart running the containers after a reboot.

You might need a watcher process to restart containers if they die, just as you would have one for a normal rails app.

Services like Tutum and Dockerize.it can make this simpler. As far as I know, Tutum will not deploy to your servers. Dockerize.it will, but is very rough (disclaimer: I'm part of the team building it).

Upvotes: 5

Andy
Andy

Reputation: 17781

You can convert your fig configuration to CoreOS formatted systemd configuration files with fig2coreos. Google App Engine supports CoreOS, or you can run CoreOS on AWS or your cloud provider of choice. fig2coreos also supports deploying to CoreOS in Vagrant for local development.

CenturyLink (fig2coreos authors) have an example blog post here:

This blog post will show you how to bridge the gap between building complex multi-container apps using Fig and deploying those applications into a production CoreOS system.

EDIT: If you are constrained to an existing host OS you can use QEMU ("a generic and open source machine emulator and virtualizer") to host a CoreOS instance. Instructions are available from the CoreOS team.

Upvotes: 2

Related Questions