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DockerUsage.md

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Using a Docker Container to Run Terraform

Prerequisites

Create the Docker Image

Run the following command to create the viya4-iac-aws Docker image using the provided dockerfile:

docker build -t viya4-iac-aws .

The Docker image, viya4-iac-aws, contains Terraform and kubectl executables. The entrypoint for the Docker image is terraform. The entrypoint will be run with subcommands in the subsequent steps.

Docker Environment File For AWS Authentication

Follow either one of the authentication methods described in Authenticating Terraform to Access AWS in order to configure authentication and enable container invocation. Store these values outside of this repository in a secure file, for example $HOME/.aws_docker_creds.env. Protect that file so that only you have Read access to it.

NOTE: Do not use quotation marks around the values in the file, and be sure to avoid any trailing blank spaces.

Now each time you invoke the container, specify the file with the --env-file option in order to pass AWS credentials to the container.

Docker Volume Mounts

Add volume mounts to the docker run command for all files and directories that must be accessible from inside the container:

  • --volume=$HOME/.ssh:/.ssh for ssh_public_key variable in the terraform.tfvars file

  • --volume=$(pwd):/workspace for a local directory where the terraform.tfvars file resides and where the terraform.tfstate file will be written.

    To grant Docker permission to write to the local directory, use the --user option.

NOTE: Local references to $HOME (or "~") need to map to the root directory / in the container.

Variable Definitions (.tfvars) File

Prepare your terraform.tfvars file, as described in Customize Input Values.

Running Terraform Commands

Preview Cloud Resources (Optional)

To preview the cloud resources before creating them, run the Docker image (viya4-iac-aws) with the plan command:

docker run --rm --group-add root \
  --user "$(id -u):$(id -g)" \
  --env-file $HOME/.aws_docker_creds.env \
  --volume $HOME/.ssh:/.ssh \
  --volume $(pwd):/workspace \
  viya4-iac-aws \
  plan -var-file /workspace/terraform.tfvars \
       -state /workspace/terraform.tfstate

Create Cloud Resources

To create the cloud resources, run the viya4-iac-aws Docker image with the apply command and the -auto-approve option:

docker run --rm --group-add root \
  --user "$(id -u):$(id -g)" \
  --env-file $HOME/.aws_docker_creds.env \
  --volume $HOME/.ssh:/.ssh \
  --volume $(pwd):/workspace \
  viya4-iac-aws \
  apply -auto-approve \
        -var-file /workspace/terraform.tfvars \
        -state /workspace/terraform.tfstate

This command can take a few minutes to complete. Once complete, Terraform output values are written to the console. The kubeconfig file for the cluster is written to [prefix]-eks-kubeconfig.conf in the current directory, $(pwd).

Display Terraform Outputs

Once the cloud resources have been created using the terraform apply command, you can display Terraform output values by running the viya4-iac-aws Docker image using the output command:

docker run --rm --group-add root \
  --user "$(id -u):$(id -g)" \
  --volume $(pwd):/workspace \
  viya4-iac-aws \
  output -state /workspace/terraform.tfstate

Modify Cloud Resources

After provisioning the infrastructure, you can make additional modifications. Update the corresponding variables with the desired values in terraform.tfvars. Then run the Docker image with the apply command and -auto-approve option again:

docker run --rm --group-add root \
  --user "$(id -u):$(id -g)" \
  --env-file $HOME/.aws_docker_creds.env \
  --volume $HOME/.ssh:/.ssh \
  --volume $(pwd):/workspace \
  viya4-iac-aws \
  apply -auto-approve \
        -var-file /workspace/terraform.tfvars \
        -state /workspace/terraform.tfstate

Tear Down Resources

To destroy all the cloud resources that you created with the previous commands, run the viya4-iac-aws Docker image with the destroy command and -auto-approve option:

docker run --rm --group-add root \
  --user "$(id -u):$(id -g)" \
  --env-file $HOME/.aws_docker_creds.env \
  --volume $HOME/.ssh:/.ssh \
  --volume $(pwd):/workspace \
  viya4-iac-aws \
  destroy -auto-approve \
          -var-file /workspace/terraform.tfvars \
          -state /workspace/terraform.tfstate

NOTE: The destroy action is irreversible.

Interacting with the Kubernetes Cluster

Creating the cloud resources writes the kube_config output value to a file, ./[prefix]-eks-kubeconfig.conf. When the Kubernetes cluster is ready, use --entrypoint kubectl to interact with the cluster.

NOTE The cluster_endpoint_public_access_cidrs value in CONFIG-VARS.md must be set to your local IP address or CIDR range.

Example Using kubectl

You can run the kubectl get nodes command with the viya4-iac-aws Docker image in order to get a list of cluster nodes. Switch the entrypoint to kubectl (--entrypoint kubectl), provide a kubeconfig file (--env=KUBECONFIG=/workspace/<your prefix>-eks-kubeconfig.conf), and pass kubectl subcommands (such as get nodes). For example, to run kubectl get nodes, run the following command:

docker run --rm \
  --env=KUBECONFIG=/workspace/<your prefix>-eks-kubeconfig.conf \
  --volume=$(pwd):/workspace \
  --entrypoint kubectl \
  viya4-iac-aws get nodes