CD with Terraform
Using Terraform to manage your infrastructure via CloudBees CodeShip Pro is as simple as setting up a service with the Terraform CLI and passing that service the commands you need. Below you will find detailed setup instructions including example configurations.
It is recommended that you be familiar with CloudBees CodeShip Pro and Docker basics before proceeding. If you are unfamiliar with either, you can reference our CodeShip Pro Getting Started Guide and the Docker 101 article for more information first.
To integrate Terraform with your CloudBees CodeShip Pro CI/CD pipeline, you will want to add a new service definition to your codeship-services.yml file.
This service can use any container you define or pull that contains the Terraform CLI, but we recommend using the official Terraform Docker image that Hashicorp publishes on Docker Hub and keeps updated with the latest releases.
In this example, we’ll use the official image as a base image for our
custom Docker image using the
FROM hashicorp/terraform:0.10.5 LABEL maintainer="Your Name, email@example.com" RUN mkdir -p /terraform WORKDIR /terraform COPY . ./
Note here that we are creating a working directory and switching to that
directory, via the
WORKDIR directive. This will allow us to simplify
our configuration a bit and avoid some pitfalls later on.
Next, we’ll make use of the above
Dockerfile in a service definition,
file. The below example covers just the Terraform service, but your
file can have any other required services defined as well.
terraform: build: dockerfile: Dockerfile volumes: - ./:/terraform encrypted_env_file: - secrets.env.encrypted
Note that in the above codeship-services.yml example we are using encrypted environment variables to pass configuration values and secrets to Terraform to avoid storing any configuration in plain text. See the Terraform documentation article on environment variables for more information on the available values and configurations.
In this case, the encrypted environment variables will contain at least the following values:
TF_VAR_aws_access_key_id = YOUR_AWS_ACCESS_KEY
TF_VAR_aws_secret_access_key = YOUR_AWS_SECRET_ACCESS_KEY
Depending on your exact Terraform configuration you will need additional environment variables, either for configuring various Terraform providers as well as configuring Terraform (remote state) itself.
Once you have your Terraform service configured, you will use this service to run the Terraform commands you need via your codeship-steps.yml file.
The below example of a codeship-steps.yml file will initialize Terraform, lint your configuration and then plan the required changes to bring your infrastructure in line with the specified Terraform configuration. It will however not apply those changes (yet).
- name: version service: terraform command: version - name: init service: terraform command: init --input=false ./ - name: validate service: terraform command: validate ./ - name: plan service: terraform command: plan --input=false --out=./codeship.tfplan
As you can see, once our service is defined we can run any Terraform commands we need to just as you would do locally using the CLI. See the Terraform documentation page on the CLI commands for a full list of available Terraform commands and options.
In the above example, it is important to note the
This instructs Terraform not to ask for any user input, and to instead
exit with an error code if input is required. This is important to avoid
having your builds hang indefinitely if input is requested.
Also note the
--out flag on the
plan command. The
plan command is
used to create an execution plan, which compares the current state of
your infrastructure to your defined configuration so that it can
determine required changes.
--out flag instructs Terraform to save this execution plan to a
file that can be used in a later step to actually apply those changes.
This is important, as it guarantees that only those changes are
applied. This also lets you validate changes manually (e.g. a feature
branch will print the planned changes, but not apply them).
To configure the actual application of infrastructure changes in your CI/CD pipeline, we will add a new step to our codeship-steps.yml file example:
# append this to the end of your codeship-steps.yml file - name: apply tag: master service: terraform command: apply --input=false ./codeship.tfplan
apply command instructs Terraform to apply the prepared changes to
To avoid this happening when you don’t intend, in this example we are
tag directive in the
codeship-steps.yml file to limit the step to only
run on a certain branch - in this case the
This example further configures Terraform to use the execution plan
created and saved to
/app/codeship.tfplan, as instructed via the
--out command in the section above.
Since Terraform relies on one or more statefiles to map real world resources to your configuration, to use Terraform with CloudBees CodeShip Pro it is important to have remote state configured and working. This is because CloudBees CodeShip Pro build machines are ephemeral and do not share any state or data in between builds. Otherwise, you might end up recreating your infrastructure on each build run.
Additionally, because CloudBees CodeShip Pro often runs concurrent builds, you may want to use a Terraform backend that supports state locking to make sure that these concurrent runs don’t result in corrupted infrastructure state.
Terraform includes an advanced guide on running Terraform in automation which provides additional information on this subject as well as advanced features not covered in this article.