terraform-notes.md

Terraform notes

Terraform allows us to build infrastructure as code.

Terraform deployment

1. Configure IAMs. See iam-notes.md for the minimum required IAM policies.

2. Apply the EKS terraform plan.

   # From eks-tf/
   terraform init
   terraform apply

3. Update the kubeconfig so that kubectl links to the cluster. This step is not strictly necessary to deploy the infrastructure, but it is handy to be able to inspect and manage the cluster.

   aws eks --region us-east-2 update-kubeconfig --name populare-cluster

4. Apply the Kubernetes terraform plan. Running terraform init is important because you are working in a different Terraform workspace. Note that load balancers and other AWS resources created by the Kubernetes deployment may not appear in the plan, but will be properly cleaned up on terraform destroy.

   # From kubernetes-tf/
   terraform init
   terraform apply

5. Browse to the app. You can find the URL using the following. It may take a minute or so for the service's hostname (backed by the load balancer) to be ready.

   kubectl get svc reverse-proxy

6. Destroy provisioned infrastructure. As discussed in this terraform PR, all required variables must be defined even for destroy actions; they are not used. First destroy the infrastructure provisioned by the Kubernetes plan, then the infrastructure provisioned by the EKS plan. There should be no resources remaining on AWS.

   # From kubernetes-tf/
   terraform destroy
   # From eks-tf/
   terraform init
   terraform destroy

Converting Kubernetes manifests to Terraform resources

As noted in this Terraform blog post, you can convert existing Kubernetes manifests into Terraform resources using the following command. Note that the manifest can only contain one Kubernetes resource.

echo 'yamldecode(file("my-manifest-file.yaml"))' | terraform console

Then add the manifest to the Terraform plan under a kubernetes_manifest resource.