Learn how to import existing configuration into Terraform
MPL-2.0 License
Learn how to import existing resources under Terraform's management.
Follow along with the Learn Terraform Import tutorial.
Run this docker command to create a container with the latest nginx image.
docker run --name hashicorp-learn --detach --publish 8080:80 nginx:latest
Verify container is running by running docker ps
or visiting 0.0.0.0:8080
in your web browser.
docker ps --filter "name=hashicorp-learn"
Initialize your workspace by running terraform init
.
Add empty resource stub to docker.tf
for the container.
resource "docker_container" "web" { }
Import the container into Terraform state.
terraform import docker_container.web $(docker inspect -f {{.ID}} hashicorp-learn)
Now the container is in your terraform configuration's state.
terraform show
Run terraform plan
. Terraform shows errors for missing required arguments
(image
, name
).
terraform plan
Generate configuration and save it in docker.tf
, replacing the empty
resource created earlier.
terraform show -no-color > docker.tf
Re-run terraform plan
.
terraform plan
Terraform will show warnings and errors about a deprecated attribute
(links
), and several read-only attributes (ip_address
, network_data
,
gateway
, ip_prefix_length
, id
). Remove these attributes from docker.tf
.
Re-run terraform plan
.
terraform plan
It should now execute successfully. The plan indicates that Terraform will
update in place to add the attach
, logs
, must_run
, and start
attributes. Notice that the container resource will not be replaced.
Apply the changes. Remember to confirm the run with a yes
.
terraform apply
There are now several attributes in docker.tf
that are unnecessary because
they are the same as their default values. After removing these attributes,
docker.tf
will look something like the following.
# docker_container.web:
resource "docker_container" "web" {
name = "hashicorp-learn"
image = "sha256:9beeba249f3ee158d3e495a6ac25c5667ae2de8a43ac2a8bfd2bf687a58c06c9"
ports {
external = 8080
internal = 80
}
}
Run terraform plan
again to verify that removing these attributes did not
change the configuration.
terraform plan
$ docker ps --filter "name=hashicorp-learn"
You can revisit `0.0.0.0:8080` in your web browser to verify that it is
still up. Also note the "Status" - the container has been up and running
since it was created, so you know that it was not restarted when you
imported it into Terraform.
Retrieve the image's tag name by running the following command, replacing the
sha256 value shown with the one from docker.tf
.
docker image inspect sha256:602e111c06b6934013578ad80554a074049c59441d9bcd963cb4a7feccede7a -f {{.RepoTags}}
Add the following configuration to your docker.tf file.
resource "docker_image" "nginx" {
name = "nginx:latest"
}
Run terraform apply
to apply the changes. Remember to confirm the run with
a yes
.
terraform apply
Now that Terraform has created a resource for the image, refer to it in
docker.tf
like so:
resource "docker_container" "web" {
name = "hashicorp-learn"
image = docker_image.nginx.latest
# File truncated...
Verify that your configuration matches the current state.
terraform apply
In your docker.tf
file, change the container's external port from 8080
to
8081
.
resource "docker_container" "web" {
name = "hashicorp-learn"
image = "sha256:602e111c06b6934013578ad80554a074049c59441d9bcd963cb4a7feccede7a5"
ports {
external = 8081
internal = 80
}
}
Apply the change. Remember to confirm the run with a yes
.
terraform apply
Verify that the new container works by running docker ps
or visiting
0.0.0.0:8081
in your web browser.
docker ps --filter "name=hashicorp-learn"
Run terraform destroy
to destroy the container. Remember to confirm
destruction with a yes
.
terraform destroy
Run docker ps
to validate that the container was destroyed.
docker ps --filter "name=hashicorp-learn"