> When applied, Terraform code would spin up a template of what the service should look like by creating an ECS task set with zero instances. Then, the developer would need to deploy the service and clone this template task set [and do a bunch of manual things]
> This meant that something as simple as adding an environment variable required writing and applying Terraform, then running a deploy
This sounds less like a problem with ECS and more like an overcomplication in how they were using terraform + ECS to manage their deployments.
I get the generating templates part for verification prior to live deploys. But this seems... dunno.
Hey, author here, I totally agree that this is not a fundamental limitation of ECS and we could have iterated on this setup and made something better. I intentionally listed this under work we decided to scope into the migration process, and not under the fundamental reasons we undertook the migration because of that distinction.
I'm with you here -- ECS deploys are pretty painless and uncomplicated, but I can picture a few scenarios where this ends up being necessary, for ex; if they have a lot of services deployed on ECS and it ends up bloating the size of the Terraform state. That'd slow down plans and applies significantly, which makes sharding the Terraform state by literally cloning the configuration based on a template a lot safer.
> ECS deploys are pretty painless and uncomplicated
Unfortunately in my experience, this is true until it isn't. Once it isn't true, it can quickly become a painful blackbox debugging exercise. If your org is big enough to have dedicated AWS support then they can often get help from engineers, but if you aren't then life can get really complicated.
Still not a bad choice for most apps though, especially if it's just a run-of-the-mill HTTP-based app
Very much agree. I have built infra on ECS with terraform at two companies now, and we have zero manual steps for actions like this, beyond “add the env var to a terraform file, merge it and let CI deploy”. The majority of config changes we would make are that process.
Yeah.... thinking about it a bit more i just don't see why they didn't set up their CI to deploy a short lived environment on a push to a feature branch.
> This meant that something as simple as adding an environment variable required writing and applying Terraform, then running a deploy
This sounds less like a problem with ECS and more like an overcomplication in how they were using terraform + ECS to manage their deployments.
I get the generating templates part for verification prior to live deploys. But this seems... dunno.