Sky Cone

Managing Applications and Infrastructure with Terraform-Deploying Infrastructure with Terraform
1. Terraform Basics and a Docker Deployment
5. Terraform Console and Output

In this post, we will look into a new Terraform configuration block called "outputs", and a new CLI, i.e. "terraform console".

~/docker# terraform apply

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_container.container_id will be created
  + resource "docker_container" "container_id" {
      + attach           = false
      + bridge           = (known after apply)
      + command          = (known after apply)
      + container_logs   = (known after apply)
      + dns              = (known after apply)
      + dns_opts         = (known after apply)
      + entrypoint       = (known after apply)
      + exit_code        = (known after apply)
      + gateway          = (known after apply)
      + hostname         = (known after apply)
      + id               = (known after apply)
      + image            = (known after apply)
      + ip_address       = (known after apply)
      + ip_prefix_length = (known after apply)
      + ipc_mode         = (known after apply)
      + log_driver       = (known after apply)
      + log_opts         = (known after apply)
      + logs             = false
      + must_run         = true
      + name             = "blog"
      + network_data     = (known after apply)
      + read_only        = false
      + restart          = "no"
      + rm               = false
      + shm_size         = (known after apply)
      + start            = true
      + user             = (known after apply)
      + working_dir      = (known after apply)

      + ports {
          + external = 80
          + internal = 2368
          + ip       = "0.0.0.0"
          + protocol = "tcp"
        }
    }

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

Plan: 2 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 23s [id=sha256:98c65d66926b2da9fbb696d43aadfaf3fee847b7185e132e199532bc549aeba5ghost:latest]
docker_container.container_id: Creating...
docker_container.container_id: Creation complete after 1s [id=0c5bcf3a7d38c094bd5a125752d845019b2b585de741ef5c284959b32edee4d3]

Apply complete! Resources: 2 added, 0 changed, 0 destroyed.

~/docker# terraform show

# docker_container.container_id:
resource "docker_container" "container_id" {
    attach            = false
    command           = [
        "node",
        "current/index.js",
    ]
    cpu_shares        = 0
    dns               = []
    dns_opts          = []
    entrypoint        = [
        "docker-entrypoint.sh",
    ]
    gateway           = "172.17.0.1"
    hostname          = "0c5bcf3a7d38"
    id                = "0c5bcf3a7d38c094bd5a125752d845019b2b585de741ef5c284959b32edee4d3"
    image             = "sha256:98c65d66926b2da9fbb696d43aadfaf3fee847b7185e132e199532bc549aeba5"
    ip_address        = "172.17.0.2"
    ip_prefix_length  = 16
    ipc_mode          = "private"
    log_driver        = "json-file"
    log_opts          = {}
    logs              = false
    max_retry_count   = 0
    memory            = 0
    memory_swap       = 0
    must_run          = true
    name              = "blog"
    network_data      = [
        {
            gateway          = "172.17.0.1"
            ip_address       = "172.17.0.2"
            ip_prefix_length = 16
            network_name     = "bridge"
        },
    ]
    network_mode      = "default"
    privileged        = false
    publish_all_ports = false
    read_only         = false
    restart           = "no"
    rm                = false
    shm_size          = 64
    start             = true
    working_dir       = "/var/lib/ghost"

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

# docker_image.image_id:
resource "docker_image" "image_id" {
    id     = "sha256:98c65d66926b2da9fbb696d43aadfaf3fee847b7185e132e199532bc549aeba5ghost:latest"
    latest = "sha256:98c65d66926b2da9fbb696d43aadfaf3fee847b7185e132e199532bc549aeba5"
    name   = "ghost:latest"
}

Provides an interactive console for evaluating expressions.
~/docker# terraform console
>

> docker_container.container_id.name
blog

> docker_container.container_id.ip_address
172.17.0.2

Ctrl+C

Output values are like the return values of a Terraform module.
Append lines into the "main.tf" file.
~/docker# vim main.tf

...
# Output name and ip address
output "IP_Address" {
  value = docker_container.container_id.ip_address
}

output "container_name" {
  value = docker_container.container_id.name
}

PS: In Terraform version 0.13, a name (e.g. output name) must start with a letter or underscore and may contain only letters, digits, underscores, and dashes. This is not an issue in Terraform version 0.11.

root@ip-172-31-18-169:/home/ubuntu/docker# terraform apply

docker_image.image_id: Refreshing state... [id=sha256:98c65d66926b2da9fbb696d43aadfaf3fee847b7185e132e199532bc549aeba5ghost:latest]
docker_container.container_id: Refreshing state... [id=0c5bcf3a7d38c094bd5a125752d845019b2b585de741ef5c284959b32edee4d3]

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

Terraform will perform the following actions:

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

Changes to Outputs:
  + IP_Address     = "172.17.0.2"
  + container_name = "blog"

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


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

Outputs:

IP_Address = 172.17.0.2
container_name = blog

root@ip-172-31-18-169:/home/ubuntu/docker# terraform destroy

docker_image.image_id: Refreshing state... [id=sha256:98c65d66926b2da9fbb696d43aadfaf3fee847b7185e132e199532bc549aeba5ghost:latest]
docker_container.container_id: Refreshing state... [id=0c5bcf3a7d38c094bd5a125752d845019b2b585de741ef5c284959b32edee4d3]

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          = "0c5bcf3a7d38" -> null
      - id                = "0c5bcf3a7d38c094bd5a125752d845019b2b585de741ef5c284959b32edee4d3" -> 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=0c5bcf3a7d38c094bd5a125752d845019b2b585de741ef5c284959b32edee4d3]
docker_container.container_id: Destruction complete after 1s
docker_image.image_id: Destroying... [id=sha256:98c65d66926b2da9fbb696d43aadfaf3fee847b7185e132e199532bc549aeba5ghost:latest]
docker_image.image_id: Destruction complete after 6s

Destroy complete! Resources: 2 destroyed.

References

Command: console

Output Values