Ideal Deployment


Haskell, But Quickly

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I’m faced with the task of deploying Oddjob, and I haven’t yet found documentation online that isn’t some variation of “Oh, deployment is easy, just use Dokku/Docker/EC2/Heroku/Ansible/Vagrant/Capistrano/Puppet/Chef/etc… etc… etc…”.

Aside from that fact that most programming advice that begins with “Oh, you just…” is unhelpful, I’ve seen very little advice given on why and when to use a particular deployment strategy, as opposed to just picking a random brand and rattling off some installation instructions.

Oddjob is an important app that will at some point support businesses with their daily administrative duties, so it’s super important that the deployment process is done right. And I don’t think the right solution will come around without first comprehensively defining the problem. In this post I’ll mull over what I think I need in my deployment process.

Minimal-shared multitenancy

I’d like to have separate instances of the app; one for each company who uses Oddjob. At least, I think that’s what I want. I’m 99% sure I at least want separate databases. I’m convinced that sharing a database among companies will be a minefield technically, and potentially also legally.

Perhaps it can be a single app instance that will switch database connections depending on the subdomain a request points to. Perhaps it should be a whole bunch of Rails apps that are isolated with virtual machines. I won’t pretend I know what’s best here, so I’d love for an experienced operations person to describe the ups and downs of each.

I need some metrics so I can better understand how much memory a server will realistically need to cope with every-day use. This along with a bunch of other metrics should be sent to something like Grafana, but this is perhaps a slightly different though related topic.

Single-step deployment

Deploying my app should only ever be a command away. Whether it’s ./scripts/deploy.sh or git push dokku master doesn’t matter. It should just be easy to deploy. I would probably want database migrations to run automatically too. This should work across instances too, so I don’t have to run this command once for every instance of the application.

Easy access to the console

There will be times when I need to SSH into the production server and run stuff in the Rails console. I don’t think “Oh, you just run docker exec -it --some --other --flags bundle exec RAILS_ENV=derp command bollocks” is acceptable for me, or for anyone. I just want this stuff to work so I can focus on making a great product for my customers.

Easy app creation

There should not be a need to keep a laundry-list of commands to run when I want to set up a new app instance for a new customer. If Acme Inc wants to run on Oddjob, I should be able to run one command that sets up an environment (possibly in a VM), clones the app, creates a database, connects the database to the app, runs migrations, etc. This new app should be included as one of the targets for the single-step deployment I described previously.

Help?

If I at some point figure all this stuff out, I promise I’ll write about it in excruciating detail, only to save the next poor fool from similar heartache. If you, my dear reader, already know all this stuff, please talk to me. I’ll even give you money (not bags of it though; I’m not loaded). This stuff shouldn’t still be this hard in 2014.