Variables ¶

Stack configuration contains variables that will be applied to a stack template (similar to values.yaml in Helm or tfvars file in Terraform). The variables from stack.yaml are passed to stack template files to render them.

Example of stack.yaml with variables region, name, organization:

name: k3s-demo
template: https://github.com/shalb/cdev-s3-web
kind: Stack
variables:
  region: eu-central-1
  name: web-static-page
  organization: Cluster.dev

The values of the variables are passed to a stack template to configure the resulting infrastructure.

Passing variables across stacks ¶

Cluster.dev allows passing variable values across different stacks within one project. This is made possible in 2 ways:

using the output of one stack as an input for another stack: {{ output "stack_name.unit_name.output" }}

Example of passing outputs between stacks:

name: s3-web-page
template: ../web-page/
kind: Stack
variables:
  region: eu-central-1
  name: web-static-page
  organization: Shalb

name: health-check
template: ../health-check/
kind: Stack
variables:
  url: {{ output "s3-web-page.outputs.url" }}

using remoteState with a syntax: {{ remoteState "stack_name.unit_name.output" }}

Global variables ¶

The variables defined on a project level are called global. Global variables are listed in the project.yaml– a configuration file that defines the parameters and settings for the whole project. From the project.yaml the variables values can be applied to all stack and backend objects within this project.

Example of the project.yaml file that contains variables organization and region:

name: demo
kind: Project
variables:
  organization: shalb
  region: eu-central-1

To refer to a variable in stack and backend files, use the {{ .project.variables.KEY_NAME }} syntax, where project.variables is the path that corresponds the structure of variables in the project.yaml. The KEY_NAME stands for the variable name defined in the project.yaml and will be replaced by its value.

Example of the stack.yaml file that contains reference to the project variables organization and region:

name: eks-demo
template: https://github.com/shalb/cdev-aws-eks?ref=v0.2.0
kind: Stack
backend: aws-backend
variables:
  region: {{ .project.variables.region }}
  organization: {{ .project.variables.organization }}
  domain: cluster.dev
  instance_type: "t3.medium"
  eks_version: "1.20"

Example of the rendered stack.yaml:

name: eks-demo
template: https://github.com/shalb/cdev-aws-eks?ref=v0.2.0
kind: Stack
backend: aws-backend
variables:
  region: eu-central-1
  organization: shalb
  domain: cluster.dev
  instance_type: "t3.medium"
  eks_version: "1.20"