Terraform

Terraform is used to create and change infrastructure resources like physical servers, VMs, containers, etc. Terraform generates configuration files with the following extensions: .tf, .tfplan, tfstate. 1

Glossary

• provider: Infrastructure software like Kuberenetes, Chef, AWS, GCP
  • From the docs: "A Provider is the logical abstraction of an upstream API"
• resources: A component of your infrastructure like an image or container

terraform shows the most commonly used commands

A common workflow

• terraform init
• terraform plan -out config.tfplan
  • Compares your prior state with the changes you've made
  • + indicates the new resources that have been created
  • Nothing is run, but a summary of changes is created
  • The changes show in the command line and in the config.tfplan file
• terraform apply
  • Does the things
  • Generates or changes the terraform.tfstate file
  • Pulls images and launches containers, etc.
• terraform show

Import

• Use import when you are importing existing resources that were created without terraform (the AWS Console, GCP, etc), and bring it under management by Terraform
  • terraform import
  • If you have an s3 bucket, you will declare that information in another file like backend.tf

Tainting a Resource

• When you 'taint' a resource, you force it to be destroyed and recreated on the next apply
  • terraform taint aws_security_group.allow_all