Sky Cone

Managing Applications and Infrastructure with Terraform-Deploying Infrastructure with Terraform
1. Terraform Basics and a Docker Deployment
9. Modules - The Image Module

In the last post, we have built the directory structure to hold the Terraform modules. In this post, we will setup the "image" module.

~/docker# ls

container  image  main.tf  outputs.tf  terraform.tfstate  terraform.tfstate.backup  variables.tf

~/docker# cd image

~/docker/image# ls

main.tf  outputs.tf  variables.tf

~/docker/image# vim main.tf

terraform {
  required_providers {
    aws = {
      source = "hashicorp/aws"
    }
    docker = {
      source = "terraform-providers/docker"
    }
  }
  required_version = ">= 0.13"
}

# Download the Docker image
resource "docker_image" "image_id" {
  name = var.image
}

~/docker/image# vim variables.tf

variable "image" {
  description = "name of the image"
}

~/docker/image# vim outputs.tf

output "image_out" {
  value = docker_image.image_id.latest
}

~/docker/image# cd ..

~/docker# terraform destroy

docker_image.image_id: Refreshing state... [id=sha256:98c65d66926b2da9fbb696d43aadfaf3fee847b7185e132e199532bc549aeba5ghost:latest]
docker_container.container_id: Refreshing state... [id=ffb0afe6004c7ecb4b205a5b7bcc903debf22aa654b5381f22180b06ad357206]

An execution plan has been generated and is shown below.
Resource actions are indicated with the following symbols:
  - destroy

Terraform will perform the following actions:

  # docker_container.container_id will be destroyed
  - resource "docker_container" "container_id" {
      - attach            = false -> null
      - command           = [
          - "node",
          - "current/index.js",
        ] -> null
      - cpu_shares        = 0 -> null
      - dns               = [] -> null
      - dns_opts          = [] -> null
      - dns_search        = [] -> null
      - entrypoint        = [
          - "docker-entrypoint.sh",
        ] -> null
      - gateway           = "172.17.0.1" -> null
      - group_add         = [] -> null
      - hostname          = "ffb0afe6004c" -> null
      - id                = "ffb0afe6004c7ecb4b205a5b7bcc903debf22aa654b5381f22180b06ad357206" -> null
      - image             = "sha256:98c65d66926b2da9fbb696d43aadfaf3fee847b7185e132e199532bc549aeba5" -> null
      - ip_address        = "172.17.0.2" -> null
      - ip_prefix_length  = 16 -> null
      - ipc_mode          = "private" -> null
      - links             = [] -> null
      - log_driver        = "json-file" -> null
      - log_opts          = {} -> null
      - logs              = false -> null
      - max_retry_count   = 0 -> null
      - memory            = 0 -> null
      - memory_swap       = 0 -> null
      - must_run          = true -> null
      - name              = "blog" -> null
      - network_data      = [
          - {
              - gateway          = "172.17.0.1"
              - ip_address       = "172.17.0.2"
              - ip_prefix_length = 16
              - network_name     = "bridge"
            },
        ] -> null
      - network_mode      = "default" -> null
      - privileged        = false -> null
      - publish_all_ports = false -> null
      - read_only         = false -> null
      - restart           = "no" -> null
      - rm                = false -> null
      - shm_size          = 64 -> null
      - start             = true -> null
      - sysctls           = {} -> null
      - tmpfs             = {} -> null
      - working_dir       = "/var/lib/ghost" -> null

      - ports {
          - external = 80 -> null
          - internal = 2368 -> null
          - ip       = "0.0.0.0" -> null
          - protocol = "tcp" -> null
        }
    }

  # docker_image.image_id will be destroyed
  - resource "docker_image" "image_id" {
      - id     = "sha256:98c65d66926b2da9fbb696d43aadfaf3fee847b7185e132e199532bc549aeba5ghost:latest" -> null
      - latest = "sha256:98c65d66926b2da9fbb696d43aadfaf3fee847b7185e132e199532bc549aeba5" -> null
      - name   = "ghost:latest" -> null
    }

Plan: 0 to add, 0 to change, 2 to destroy.

Changes to Outputs:
  - IP_Address     = "172.17.0.2" -> null
  - container_name = "blog" -> null

Do you really want to destroy all resources?
  Terraform will destroy all your managed infrastructure, as shown above.
  There is no undo. Only 'yes' will be accepted to confirm.

  Enter a value: yes

docker_container.container_id: Destroying... [id=ffb0afe6004c7ecb4b205a5b7bcc903debf22aa654b5381f22180b06ad357206]
docker_container.container_id: Destruction complete after 1s
docker_image.image_id: Destroying... [id=sha256:98c65d66926b2da9fbb696d43aadfaf3fee847b7185e132e199532bc549aeba5ghost:latest]
docker_image.image_id: Destruction complete after 7s

Destroy complete! Resources: 2 destroyed.

~/docker# cd image

~/docker/image# terraform init

Initializing the backend...

Initializing provider plugins...
- Finding latest version of hashicorp/aws...
- Finding latest version of terraform-providers/docker...
- Installing hashicorp/aws v3.9.0...
- Installed hashicorp/aws v3.9.0 (signed by HashiCorp)
- Installing terraform-providers/docker v2.7.2...
- Installed terraform-providers/docker v2.7.2 (signed by HashiCorp)

The following providers do not have any version constraints in configuration,
so the latest version was installed.

To prevent automatic upgrades to new major versions that may contain breaking
changes, we recommend adding version constraints in a required_providers block
in your configuration, with the constraint strings suggested below.

* hashicorp/aws: version = "~> 3.9.0"
* terraform-providers/docker: version = "~> 2.7.2"

Terraform has been successfully initialized!

You may now begin working with Terraform. Try running "terraform plan" to see
any changes that are required for your infrastructure. All Terraform commands
should now work.

If you ever set or change modules or backend configuration for Terraform,
rerun this command to reinitialize your working directory. If you forget, other
commands will detect it and remind you to do so if necessary.

~/docker/image# terraform plan

var.image
  name of the image

  Enter a value: ghost:alpine

Refreshing Terraform state in-memory prior to plan...
The refreshed state will be used to calculate this plan, but will not be
persisted to local or remote state storage.


------------------------------------------------------------------------

An execution plan has been generated and is shown below.
Resource actions are indicated with the following symbols:
  + create

Terraform will perform the following actions:

  # docker_image.image_id will be created
  + resource "docker_image" "image_id" {
      + id     = (known after apply)
      + latest = (known after apply)
      + name   = "ghost:alpine"
    }

Plan: 1 to add, 0 to change, 0 to destroy.

------------------------------------------------------------------------

Note: You didn't specify an "-out" parameter to save this plan, so Terraform
can't guarantee that exactly these actions will be performed if
"terraform apply" is subsequently run.

Enter "ghost:alpine" when prompted.

~/docker/image# terraform apply

var.image
  name of the image

  Enter a value: ghost:alpine


An execution plan has been generated and is shown below.
Resource actions are indicated with the following symbols:
  + create

Terraform will perform the following actions:

  # docker_image.image_id will be created
  + resource "docker_image" "image_id" {
      + id     = (known after apply)
      + latest = (known after apply)
      + name   = "ghost:alpine"
    }

Plan: 1 to add, 0 to change, 0 to destroy.

Do you want to perform these actions?
  Terraform will perform the actions described above.
  Only 'yes' will be accepted to approve.

  Enter a value: yes

docker_image.image_id: Creating...
docker_image.image_id: Still creating... [10s elapsed]
docker_image.image_id: Still creating... [20s elapsed]
docker_image.image_id: Creation complete after 21s [id=sha256:a7d409c8a8af50ce6df5cc5cb94600b657acc9cfd82216d89a83730467bdd439ghost:alpine]

Apply complete! Resources: 1 added, 0 changed, 0 destroyed.

Outputs:

image_out = sha256:a7d409c8a8af50ce6df5cc5cb94600b657acc9cfd82216d89a83730467bdd439

Enter "ghost:alpine" when prompted.

~/docker/image# terraform destroy

var.image
  name of the image

  Enter a value: yes

docker_image.image_id: Refreshing state... (ID: sha256:dddc4523848b1834b333dcd5e00b5234...f260c9a7d6082d1ecf832d2fa5ghost:alpine)

An execution plan has been generated and is shown below.
Resource actions are indicated with the following symbols:
  - destroy

Terraform will perform the following actions:

  - docker_image.image_id


Plan: 0 to add, 0 to change, 1 to destroy.

Do you really want to destroy?
  Terraform will destroy all your managed infrastructure, as shown above.
  There is no undo. Only 'yes' will be accepted to confirm.

  Enter a value: yes

docker_image.image_id: Destroying... (ID: sha256:dddc4523848b1834b333dcd5e00b5234...f260c9a7d6082d1ecf832d2fa5ghost:alpine)
docker_image.image_id: Destruction complete after 1s

Destroy complete! Resources: 1 destroyed.

Enter "ghost:alpine" when prompted.