Devops code structure

Ansible Structure

Sunbird devops is split across two repositories.

• Public repo
  • Ansible roles.
  • Ansible playbooks.
  • Simple deployment scripts.
  • Docker Image scripts.
  • Azure ACS engine scripts which help in setting up Docker swarm on Azure.
• Private repo
  • Ansible inventories.
  • Deployment pipeline scripts.

Ansible Inventory structure

Following inventory structure is used:

`-- inventories
    `-- {env}  #name of the environment
    |   `-- group_vars
    |   |   `-- {env}-es.yml  # ES specific variables
    |   |   `-- ...
    |   |   `-- ...
    |   |   `-- {env}.yml  # Variables
    |   `-- hosts  # Ansible inventory definition
    |   `-- secrets.yml  # Secrets, encrypted using Ansible vault

Default values for variables should be put in {role}/defaults/main.yml.

Deployment Pipeline scripts

• Sunbird environments are managed using Jenkins.
• Pipeline scripts for various tasks ranging from deployment, taking DB backups to purging old logs, etc.
• This wiki explains how the Sunbird CI pileline has been setup using Jenkins.

Service deploy script flow

Image: Edit Link

Sunbird service deployment happens as follows:

• When a service deployment is triggered, Jenkins slave runs the corresponding ansible playbook.
• The playbook connects to Docker swarm manager over SSH.
• It then creates the necessary configs, secrets, stack files to deploy the service.
• Runs stack deploy.
• The stack deploy will start the corresponding service in Docker swarm agents as per the stack definition (image, replications, resource constraints, etc).

Custom images

• Custom images of open-source libraries/tools – like nginx, kong, etc – are present in images directory.
• Customizing an image involved the following (illustration uses the sunbird proxy image created using nginx):
  • Dockerfile: Defines how the image should be built.
  • Jenkinsfile.build: Jenkins pipeline script which uses the docker file to build the image and upload it to docker hub.
  • Jenkinsfile.silver: Jenkins pipeline script which tags the specified version of the image as silver.
  • Jenkinsfile.gold: Jenkins pipeline script which tags the specified version of the image as gold.