How To Build a CI/CD Pipeline for Microservices Architecture

CI/CD has become crucial in the modern fast-paced software development process because it enables quick application releases, as well as reliable updates over time. These pipelines are even more important for developers who use microservices because each one must be coordinated to provide the required functionality in the production software. However, creating these CI/CD pipelines isn’t a walk in the park, primarily due to the distributed design of the microservices architecture. Let’s look at a basic build of a CI/CD pipeline to get a feel of how it works and the tools you need.

How To Setup a CI (Continuous Integration) Pipeline

Continuous Integration is the practice or idea of putting together (merging) code changes from different developers into a central repository, from where automated builds and tests can be triggered. So basically, a CI pipeline is an automated pathway for building and testing code changes done by a team of developers. This ensures the code (microservice) only gets to the delivery stage once it is clean (error-free).

A common tool used to handle the CI pipeline is Jenkins, which is an open-source server. You’ll also need a central repository from which Jenkins can pull code changes, and Git is popularly used for this. Platforms like GitLab, GitHub, and BitBucket are commonly used as the single source of truth.

After installing and setting up Jenkins (accessed via http://localhost:8080), create a Jenkins pipeline job to automatically build and test code changes after pulling them once edits are detected. Jenkins jobs use the Jenkins pipeline plugin to create the pipeline as code. You’ll also have to install the Git plugin to link Jenkins with your central repository and the Maven plugin to enable building and testing.

Build Stage Code

To build the microservice, use the command “mvn clean install”

Test Stage Code

This stage should invoke the code “mvn test”

This pipeline is designed for a Java project that uses Apache Maven as the build and test tool for continuous integration, hence the maven (mvn) keyword. 

Testing is perhaps the most important part of the CI pipeline, and the two types of testing processes carried out are:

• Unit Tests: This checks the smallest, individual components of the code
• Integration Tests: Once the green light is given for the unit tests, integration testing checks if these components work together correctly.

The primary goal of continuous integration is to detect integration issues like bugs and conflicts early when it’s cheaper and easier to fix. If it was a large file of monolithic code, the late merging would cause long debugging cycles.

How To Setup a CD (Continuous Delivery) Pipeline

As soon as the code changes pass the testing stage and are sent to the orchestration tool (Kubernetes in this case), they should be delivered automatically to enable quick release cycles. For CD, we’ll also use Jenkins, and the first step is to create a Jenkins job that will deploy the code changes into a real-world production environment. 

Delivery Stage Code

For delivery, we’ll use Kubernetes as the target, so you’ll need a Kubernetes configuration file to deploy the microservice into a Kubernetes cluster. Let’s name it “deployConfi” in this case. The command will be “kubectl apply -f deployConfi.yml”

CD pipelines basically place the integrated services that make up the application build (artifact) in a simulated production environment that is similar to the real world to run E2E (End to End), security, performance, and UA (User Acceptance) tests. The goal is to ensure the final build is production ready, stable, secure, and ready to use.

All these CI/CD commands are written using the Jenkins Pipeline Domain Specific Language’s Groovy syntax, and the final step in the pipeline is to trigger the Jenkins job to begin whenever the code changes are error free in the central repository.

However, it is important to implement risk management into the CD pipeline, which involves having a mechanism to roll back changes if issues occur after delivery. Technically, this means reverting back to the old application version without the updated microservice to prevent downtimes or misbehavior.

After delivery, the devops engineer should continuously monitor and optimize the health and performance of both pipelines by identifying and eliminating bottlenecks using feedback loops.

What About Continuous Deployment?

Continuous Delivery and Continuous Deployment are often used interchangeably, but there is a slight difference between them. With the former, the pipeline automates the testing processes up to the release step, where human intervention is needed to manually approve the build into production. But with continuous deployment, this final step is also automated.

However, this step should be handled delicately using strategies like Blue-Green, Rolling, or Canary deployments to ensure minimal or zero downtime by controlling how real-world traffic and production infrastructure are applied to the artifact.

In cloud environments where IaC is applied, deployment also includes providing or updating the required infrastructure to run the artifact optimally. This includes coding the database, virtual machine, and load balancing parameters to handle the update. Tools like Terraform, Azure Resource Manager, and AWS CloudFormation are commonly used IaC tools for this task.

Why Use the Microservices Architecture?

The whole microservices architecture with CI/CD pipeline usage stages seems complicated, so why bother? With microservices, developers get to break down a complex application into simpler, independent services that communicate with each other using APIs. Each of these microservices can then be developed, deployed into production, improved, and scaled independently, and the benefits of working this way are:

• Faster development
• Quicker time to deployment (production)
• Better fault tolerance
• Increased scalability

Conclusion

This is a general overview of how to build a CI/CD pipeline for modern software development teams. There are several tools that you can use, but the blueprint is generally the same because the goal of these two pipelines is to hasten the microservice production process from idea to final artifact build that is ready for the business use. The easiest way to think about this pipelining is like creating an assembly line for cars, cables, electronics, etc., to bring different components together in the most efficient way to shorten the time to market.

Amelia Olivia