CI/CD

Overview

Since there are many DIGIT services and the development code is part of various git repos, you need to understand the concept of cicd-as-service which is open sourced. This page also guides you through the process of creating a CI/CD pipeline.

As a developer - To integrate any new service/app to the CI/CD below is the starting point:

Once the desired service is ready for the integration: decide the service name, type of service, whether DB migration is required or not. While you commit the source code of the service to the git repository, the following file should be added with the relevant details which are mentioned as below:

Build-config.yml –It is present under build directory in each repository

https://github.com/egovernments/core-services/blob/master/build/build-config.yml

This file contains the below details which are used for creating the automated Jenkins pipeline job for your newly created service.

# config:
#   - name: < Name of the job, foo/bar would create job named bar inside folder foo >
#     build:
#     - work-dir: < Working directory of the app to be built >
#       dockerfile: < Path to the dockerfile, optional, assumes dockerfile in working directory if not provided>                                                
#       image-name: < Docker image name >

While integrating a new service/app, the above content needs to be added in the build-config.yml file of that app repository. For example: If we are on-boarding a new service called egov-test, then the build-config.yml should be added as mentioned below.

config:
   - name: core-services/egov-test
     build:
     - work-dir: egov-test
       dockerfile: build/maven/Dockerfile
       image-name: egov-test

If a job requires multiple images to be created (DB Migration) then it should be added as below,

config:
   - name: core-services/egov-test
     build:
     - work-dir: egov-test
       dockerfile: build/maven/Dockerfile
       image-name: egov-test
     - work-dir: egov-test/src/main/resources/db
       dockerfile: build/maven/Dockerfile
       image-name: egov-test-db

Note - If a new repository is created then the build-config.yml should be created under the build folder and then the config values are added to it.

The git repository URL is then added to the Job Builder parameters

When the Jenkins Job => job builder is executed the CI Pipeline gets created automatically based on the above details in build-config.yml. Eg: egov-test job will be created under core-services folder in Jenkins because the “build-config was edited under core-services” And it should be the “master” branch only. Once the pipeline job is created, it can be executed for any feature branch with build parameters (Specifying which branch to be built – master or any feature branch).

As a result of the pipeline execution, the respective app/service docker image will be built and pushed to the Docker repository.

Continuous Integration (CI)

The Jenkins CI pipeline is configured and managed 'as code'.

New Service Integration - Example URL - https://builds.digit.org/

Job Builder – Job Builder is a Generic Jenkins job which creates the Jenkins pipeline automatically which are then used to build the application, create the docker image of it and push the image to docker repository. The Job Builder job requires the git repository URL as a parameter. It clones the respective git repository and reads the build/build-config.yml file for each git repository and uses it to create the service build job.

‌Check git repository URL is available in ci.yaml****‌‌

If git repository URL is available build the Job-Builder Job

If git repository URL is not available ask the devops team to add.

Continuous Deployment (CD)‌

The services deployed and managed on a Kubernetes cluster in cloud platforms like AWS, Azure, GCP, OpenStack, etc. Here, we use helm charts to manage and generate the Kubernetes manifest files and use them for further deployment to respective Kubernetes cluster. Each service is created as charts which will have the below-mentioned files in it.

billing-service/   # Directory – name of the service/app
Chart.yaml         # A YAML file containing information about the chart
LICENSE            # OPTIONAL: A plain text file containing the license for the chart
README.md          # OPTIONAL: A human-readable README file
values.yaml        # The default configuration values for this chart
templates/         # A directory of templates that, when combined with values, will generate valid Kubernetes manifest files.

To deploy a new service, we need to create the helm chart for it. The chart should be created under the charts/helm directory in DIGIT-DevOps repository.

Github repository 
    https://github.com/egovernments/DIGIT-DevOps/deploy-as-code/helm/charts

We have an automatic helm chart generator utility which needs to be installed on the local machine, the utility will prompt for user inputs about the newly developed service( app specifications) for creating the helm chart. The requested chart with the configuration values (created based on the inputs provided) will be created for the user.

‌ _Name of the service? test-service Application Type? NA Kubernetes health checks to be enabled? Yes Flyway DB migration container necessary? No Expose service to the internet? Yes Route through API gateway [zuul] No Context path? hello_‌

The generated chart will have the following files.

create Chart.yaml
create values.yaml
create templates/deployment.yaml
create templates/service.yaml
create templates/ingress.yaml

This chart can also be modified further based on user requirements.

The Deployment of manifests to the Kubernetes cluster is made very simple and easy. We have Jenkins Jobs for each state and environment-specific. We need to provide the image name or the service name in the respective Jenkins deployment job.

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‌The deployment Jenkins job internally performs the following operations,‌

Reads the image name or the service name given and finds the chart that is specific to it.
Generates the Kubernetes manifests files from the chart using helm template engine.
Execute the deployment manifest with the specified docker image(s) to the Kubernetes cluster.