Support Gitlab managed Terraform backend

Closes: #171 (closed) Related: #240 (closed)

Adds support for multiple backend types, starting with gcs and http.

To do

• Solidify approach after feedback
• Update documentation to match approach

References

• https://docs.gitlab.com/ee/user/infrastructure/

Testing

http backend (GitLab)

# ./secrets/gitlab-cluster-rc.sh

# Terraform configs for resources
GCLOUD_ZONE="<zone>"
TERRAFORM_PREFIX="<prefix>"
SSH_USER="ansible"
VAULT_PASSWORD_FILE="vault-password-file"
GOOGLE_JSON_FILE="google-credentials.json"

# Terraform backend configs for gitlab
BACKEND=gitlab
GITLAB_API_USERNAME=<username> # your GitLab username, or username of a bot
GITLAB_API_TOKEN=<apiToken> # API token generated under Settings with 'api' access
GITLAB_API_V4_URL=https://gitlab.com/api/v4 # this is the value if using .com
GITLAB_PROJECT_ID=<project ID> # available on project summary page
GITLAB_PROJECT_NAME=<project name> # the project name - can be an existing or blank/new project for testing

✅ Running ./provision-cluster successfully created backend in GitLab project and resources in GCS.

To see backend state JSON: https://gitlab.com/api/v4/projects/<project ID>/terraform/state/<project name>

GCS backend

# ./secrets/gitlab-cluster-rc.sh

# Terraform configs for resources
GCLOUD_ZONE="<zone>"
TERRAFORM_PREFIX="<prefix>"
SSH_USER="ansible"
VAULT_PASSWORD_FILE="vault-password-file"
GOOGLE_JSON_FILE="google-credentials.json"

# Terraform backend configs for GCS
BACKEND=gcs
STATE_GCS_BUCKET="gcsBucketName"
GCS_PREFIX="tf"

✅ Running ./provision-cluster successfully created backend and resources in GCS.