cnp-azuredevops-libraries

Reusable pipeline components for CNP Azure DevOps pipelines

Terraform workflow templates

The template files below contain steps to add Terraform Init/Plan/Apply/Destroy tasks to a pipeline.

├── scripts                                  
├── steps
│   └── terraform-precheck.yaml             # Precheck stage tasks
│   └── terraform.yaml                      # Terraform plan and apply stage tasks
├── tasks   
├── vars   

Reusing templates:

1. Create the required folder structure in your repository

2. Add the cnp-azure-devops-libraries repository resource as below

   resources:  
     repositories:
     - repository: cnp-azuredevops-libraries
       type: github
       ref: refs/heads/master
       name: hmcts/cnp-azuredevops-libraries
       endpoint: 'hmcts (1)'  
    

3. Use the vars/input-variables.yaml template to add the common variables to your pipeline.

   Make sure you use the correct syntax when declaring a mixture of regular variables and templates, like below.

   Syntax example

   variables:
     # a regular variable
     - name: myvariable
       value: myvalue
     # a variable group
     - group: myvariablegroup
     # a reference to a variable template
     - template: myvariabletemplate.yml

   Full example

   variables:
     - name: timeoutInMinutes
       value: 60
     - name: agentPool
       value: ubuntu-18.04
     - name: build
       value: $(Build.BuildNumber)
     - name: product
       value: cft-platform
     - name: terraformInitSubscription
       value: b8d29n39-8007-49m0-95b8-3c8691e90kb
     - template: vars/input-variables.yaml@cnp-azuredevops-libraries

   More information on the correct syntax when using regular variables, variables groups and templates.

4. Add the terraform-precheck.yaml template to a Precheck stage

5. Add the terraform.yaml template to a TerraformPlanApply stage

   see Example refactored pipeline

6. First time pipeline run:

   • Run build with the Terraform plan option. State file will be created in new location
   • Copy state file from old location to overwrite new state file
   • Run build with Terraform plan to confirm plan reflects migrated state file

7. Run pipeline with plan/apply option as required

State file:

• In storage accounts in the HMCTS-CONTROL subscription
• Storage account name derived from the resources subscription id as below:

  'c' + '1st-8th character of subscription id' + '25th-36th character of subscription id' + 'sa'
  e.g. 'cb72ab7b703b0f2c6a1bbsa'

• Stored in the 'subscription-tfstate' storage container in the folder path derived as below:

  'location/product/build repo name/environment/component name/terraform.tfstate'
  e.g. 'UK South/cft-platform/azure-platform-terraform/sbox/shutter/terraform.tfstate'

Required terraform folder structure:

Template requires the below folder structure for the build repository.

Repo
├── components                                         
│   └── <a> (e.g. network)                             # group of .tf files
│   │       └── .terraform-version (symlink)           # link to .terraform-version at root level (for local testing)
│   │       │                                            command: ln -s ../../.terraform-version .terraform-version
│   │       └── *.tf
│   └── <n> 
├── environments                                       # Environment specific .tfvars files
│   └── <env>
│   │    └── *.tfvars
├── azure_pipeline.yaml
├── .terraform-version                                 # terraform version (read by tfenv)

Multiple regions

Some repositories have separate tfvars files based on region i.e. UK South or UK West and having all enviroment variables in a single tfvars file may not meet the requirement. If you need to use a different set of variables for your build then you can pass the multiRegion parameter and set this as true, the default is false.

Using multiple region support requires the below environments folder structure for the build repository.

Repo
├── environments                                       # Environment specific .tfvars files
│   └── <env>
│   │    └── <location>.tfvars                         # Region specific tfvars file without spaces e.g. prod-ukwest.tfvars

With this a different variable file will be used. An example can be found in the hub-panorama repo.