Terraform

• Infrastructure as code tool
• Access among multiple providers such as AWS, GCP, Azure,etc

Terraform Providers

• plugin to talk to a specific set of APIs
• providers that terraform supports eg . AWS
• So we need to set up the configuration for the provider we need

Terraform Basic Commands

terraform init

• going to look into all the configuration in the main.tf file
• will download all the plugins for all the providers, eg. AWS, Azure, GCP
• adds a .terraform/init folder with all the plugins

terraform plan

• does a dry run of the code
• will show if it will delete any instances modify instances
• quick sanity check to check for any changes

terraform apply

• runs another dry run
• executes the commands to run application
• will always refresh terraform.tfstate
• running apply again doesn't deploy the resource again
• terraform apply --auto-approve
  • skips having to type on YES all the time

terraform destroy

• destroys the resources defined in terraform

Other Notes

• Order of the resources of code does not matter in terraform
• No matter how many times we apply terraform, we give it the blueprint,
• We define what our entire infrastructure looks like, state will always match what is in terraform code
• The state is always refreshed when you click on apply, it will figure out what needs to be added changed or destroyed

File: terraform.tfstate

• will always contains what is deployed in the provider, eg. aws
• DO NOT mess with this file. it will destroy terraform and will create mismatches in your configuration

main.tf

• contains definition for resources

output.tf

• will print the values of the resources we want to deploy

provider.tf

• providers for the APIs we're using eg. aws, gcp or azure

state_config.tf

• can configure it to check state via storage eg. s3 , this useful for teams where people are modifying and deploying new resources

terraform.tfvars

• never pushed keep all your vars here, will be read in variables.tf

variables.tf

• where we define the variables we're going to use
• this is where they're declared

Terraform Troubleshooting and Debugging

• Setting console logging to verbose
• Useful for debugging deployment issues

Set logging to verbose

$ export TF_LOG=true

Unset logging

$ export TF_LOG=

Common Errors

State is locked

Error locking state: Error acquiring the state lock: ConditionalCheckFailedException: The conditional request failed
ID:        xxxxxxxx-1386-5164-fe11-bbb268404105
Path:      xxxxxxxxx-ap-southeast-1-terraform-state/aws-ecr-terraform.tfstate
Operation: OperationTypeApply
Who:       eddrichjanzzenang@eja.lan
Version:   0.14.8
Created:   2021-03-29 13:42:43.630445 +0000 UTC
Info:

Solution:

# terraform force-unlock <ID>
$ terraform force-unlock xxxxxxxx-1386-5164-fe11-bbb268404105