CODEWITHSUNDEEP
terraformmultistage
user4374365
user4374365

Reputation: 1

Terraform multi-stage resource initialization with temporary resources

I use terraform to initialize some OpenStack cloud resources.

I have a scenario where I would need to initialize/prepare a volume disk using a temporary compute resource. Once volume is fully initialized, I would no longer need the temporary compute resource but need to attach to another compute resource (different network configuration and other settings making reuse of first impossible). As you might have guessed, I cannot reach directly the expected long term goal without the intermediary step.

I know I could drive a state machine or some sort of processing queue from outside terraform to achieve this, but I wonder if it was possible to do it nicely in one single run of terraform.

The best I could think of, is that a main terraform script would trigger creation/destruction of the intermediate compute resource by launching a another terraform instance responsible just for the intermediate resources (using terraform apply followed by terraform destroy). However it requires extra care such as ensuring unique folder to deal with concurrent "main" resource initialization and makes the whole a bit messy I think.

Upvotes: 0

Views: 365

Answers (1)

Marcin
Marcin

Reputation: 239005

I wonder if it was possible to do it nicely in one single run of terraform.

Sadly, no. Any "solution" which you could possibly implement for that (e.g. running custom scripts through local-exec, etc) in a single TF will only be convoluted mess, and will only lead to more issues that it solves in the long term.

The proper way, as you wrote, is to use dedicated CI/CD pipeline for a multistage deployment. Alternatively, don't use TF at all, and use other IaC tool.

Upvotes: 0

Related Questions