container.training/slides/terraform/variables.md

Variables

• At this point, we are probably:

  • duplicating a lot of information (e.g. zone, number of nodes...)

  • hard-coding a lot of things as well (ditto!)

• Let's see how we can do better!

---

Input variables

Declaring an input variable:

variable "location" {
  type    = string
  default = "europe-north1-a"
}

Using an input variable:

resource "google_container_cluster" "mycluster" {
  location = var.location
  ...
}

---

Setting variables

Input variables can be set with:

• environment variables (export TFVAR_location=us-west1)

• a file named terraform.tfvars (location = "us-west1")

• a file named terraform.tfvars.json

• files named *.auto.tfvars and *.auto.tfvars.json

• command-line literal values (-var location=us-west1)

• command-line file names (-var-file carbon-neutral.tfvars)

The latter taking precedence over the former.

---

Local values

Declaring and setting a local value:

locals {
  location = var.location != null ? var.location : "europe-north1-a"
  region   = replace(local.location, "/-[a-z]$/", "")
}

We can have multiple locals blocks.

Using a local value:

resource "google_container_cluster" "mycluster" {
  location = local.location
  ...
}