Overview of CI/CD Pipelines with Kubernetes

This is an article from DZone’s 2022 Kubernetes in Enterprise Trends report.

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Automation and cross-functional collaboration are two fundamental features of a DevOps model. As one of the core components of the DevOps framework, Continuous Integration and Continuous Delivery (CI/CD) pipelines accelerate application delivery by automating various phases of the software development lifecycle. While Kubernetes inherently automates the distribution, scaling, and management of applications by deploying and organizing them into flexible, portable containers, the adoption of CI/CD-based workflows brings a plethora of additional features by offering iterative cycles of configuration merging and testing. Is.

In this article, we discuss the CI/CD approach in the Kubernetes ecosystem, best practices for implementing an efficient CI/CD framework, and popular open-source CI/CD tools.

CI/CD Pipeline in the Kubernetes Ecosystem

Kubernetes provides a combination of deployment objects, rollout strategies, and resource controllers to help automate the building, testing, and integration processes of the CI/CD pipeline. Beyond container-based deployment, Kubernetes powers modern CI/CD pipelines by using efficient orchestration algorithms that schedule batch jobs, enable sequential rollouts, and autoscale workloads. With containerized deployment, DevOps teams can efficiently automate the design, testing, coding, integration, delivery, and deployment of applications for comprehensive automation.

Figure 1: Bridge-based CI/CD Pipeline

Kubernetes CI/CD approach

Kubernetes supports two approaches to implementing a CI/CD pipeline that essentially defines how configuration changes are implemented in a workflow. These include pull-based pipelines and push-based pipelines.

bridge-based pipeline

In a bridge-based CI/CD pipeline, code and infrastructure changes are implemented within the cluster. This architecture relies on an agent (often referred to as a controller) within the cluster that scans the cluster state and compares it to a declarative desired state. In instances where there is a difference between the desired configuration and the cluster state, the controller applies the changes automatically.

To help understand how a bridge-based CI/CD pipeline can support your cloud-native workloads, let’s learn some of its advantages and disadvantages:

bridge-based CI/CD pipeline

the gain Harm
  • It ensures continuous security by removing manual overheads to provide administrator access for each cluster change.
  • It is easier to scale similar deployments as the controller automatically applies changes to the cluster without the need for manual efforts.
  • This only works for Kubernetes deployments.
  • In a multi-cluster framework, each Kubernetes cluster must adopt a bridge-based framework.

push-based pipeline

It is an agentless pipeline architecture that uses external systems to trigger deployment. In a push-based pipeline, configuration changes are made to a repository, which then updates the environment by adding commits to a pipeline that were already executed successfully.

Push-Based CI/CD Pipeline

Figure 2: Push-Based CI/CD Pipeline

Despite its quick implementation and popularity, organizations should assess the use cases of a push-based pipeline before choosing it for their cloud-native workloads. Some of its advantages and disadvantages are listed below:

Push-Based CI/CD Pipeline

the gain Harm
  • It is easier to implement than a bridge-based pipeline.
  • It provides flexibility and can be applied to environments other than Kubernetes.
  • Push pipelines standardize the deployment of workloads to both cloud and traditional environments, making it ideal for hybrid/multi-cluster models.
  • This requires external administrator access to the CI/CD pipeline.
  • This compromises security because the architecture relies on opening the cluster firewall to external services.

Considerations for Kubernetes CI/CD Pipelines

The development and deployment of applications on a Kubernetes-based CI/CD pipeline depends on an autonomous framework of various Kubernetes tools, services, and best practices that ensure security, high performance, and agility. Some of the key considerations for implementing efficient Kubernetes CI/CD pipelines are automated testing, validation, and rollback.

automated testing

Detecting errors and defects during the early stages of the workflow helps increase application agility. As a recommended design, the test environment should match the production environment in order to streamline the build, test, and cycles in different environments. Continuous, automated testing also helps in creating sustainable application builds that ensure that the code is readable, debuggable and maintainable.

validation

Since multiple builds can be deployed at once in a CI/CD pipeline, it is important to have an automated validation process to track failure points in large-scale deployments. With appropriate validation, the pipeline integrates code changes seamlessly, thereby reducing vulnerability detection overhead.

recycling

Rollback ensures code cleanliness by reinstalling the previous, stable deployment if flaws occur with a new commit/version. As one of the most important considerations in workflow design, it is important to adopt a planned roll-back strategy that protects the availability of workloads in production.

Benefits of CI/CD Pipelines in the Kubernetes Ecosystem

Benefits of using Kubernetes-based CI/CD pipelines include:

  • short release cycle – Automated testing and deployment eliminates delays in pushing changes to production. Iterative CI/CD validation also avoids code merge conflicts, accelerating frequent patching in later production and updating workflows.
  • auto scaling Containerizing applications makes it easier to scale and replicate workloads with changing traffic demands. Kubernetes deployment objects such as ReplicaSet, Deployment, and StatefulSet help automatically spin up replicas of containerized workloads to ensure efficient load balancing and near-zero downtime.
  • node-usage efficiency – With Kubernetes-based workflows, administrators can set optimal resource limits and requests, ensuring efficient use of server compute, memory, and storage resources.
  • microservices-based deployment – Kubernetes implements the deployment of applications in portable containers with all the necessary libraries and resources. The framework allows developers to leverage microservices for simple, cloud-native application deployment and management.

Popular open-source Kubernetes CI/CD tools

The open-source CI/CD tools are known for providing flexibility in deploying, scaling and managing workloads in Kubernetes CI/CD pipelines. While organizations often adopt the most popular platforms, it is imperative to analyze the business and technical requirements before choosing one. Some popular open-source CI/CD tools include Spinnaker, Jenkins X, and Argo CD:

tool description the gain Harm
sailboat A multi-cloud CI/CD platform that relies on JSON to implement and configure software delivery pipelines. The platform implements built-in, production-safe deployment strategies to help you deliver composite applications in your target environment without writing any scripts.

By adhering to an API-based modular architecture, Spinnaker allows DevOps teams to seamlessly integrate external services for increased security, visibility and cost efficiency.

  • Rapid release and deployment
  • Integrated Deployment Strategies
  • Rollback can be implemented with a single click
  • Out-of-the-box support for multi-cloud and hybrid models
  • Adds operational overhead to the orchestration of multiple underlying microservices
  • Allows only irreversible deployment
jenkins x Helps accelerate software delivery by creating previews on pull requests using Git as a single source of truth. Since the platform provides an official Kubernetes plugin, it is considered the most widely adopted CI/CD tool for Kubernetes workloads.
  • Provides automated feedback on pull requests and issues
  • Depends on Git as a Single Source of Truth
  • Limited to Kubernetes groups and works entirely on GitHub
  • Disabled UI and Dashboard Views
argo cd A declarative, Kubernetes-centric continuous delivery tool that receives commits made in a centralized repository and deploys them to a production cluster.

The platform relies on an agent that is installed directly within the cluster to implement bridge-based GitOps for managing application updates and infrastructure configuration.

  • kubernetes-native deployment
  • Implements portability and flexibility
  • Uses standard, declarative patterns for application delivery
  • Relying on a bridge-based mechanism, it requires a long implementation cycle
  • Doesn’t offer continuous integration out of the box

Best practices for implementing CI/CD with Kubernetes

Although approaches to adopting the DevOps model may vary with different use cases, let’s discuss some commonly recommended practices for implementing efficient Kubernetes CI/CD pipelines.

Diligent selection of an ideal environment

Developers should diligently choose the appropriate version of Kubernetes as it further defines the choice of CI/CD tools and methodologies. Depending on the complexity of the deployed workload, developers should also be sure to choose the ideal setup between managed, self-hosted, cloud-based or on-premises as these are important aspects of the CI/CD workflow including scaling, security and affect. cost.

safe secret

It is recommended not to include cluster privacy and configuration in container images or pod definitions. Alternatively, secrets should be stored in an encrypted vault or defined as Kubernetes secret objects. Additionally, it is recommended to declare the configuration settings in the config map, which is then placed on the container. The approach helps to define specific configurations for each environment without exposing the data in the container.

Using GitOps Workflow

GitOps is a modern integration workflow that ensures predictability, visibility, and ease of use. Using a single source of truth simplifies CI/CD-based application delivery and infrastructure control, while streamlining code integration and eliminating redundancy.

summary

Kubernetes continues to maintain favorable adoption in modern DevOps workflows as it provides seamless scalability and flexibility in modern application delivery. When configuring large-scale clusters, managing the Kubernetes ecosystem can quickly become challenging. Overcoming such complexities often requires a combination of recommended practices, diligently designed architecture, and efficient tools that help achieve agility, scalability and widespread automation. Although Kubernetes powers CI/CD workflows, the open-source platform is also recommended for configuring native pipelines to reduce testing and deployment overhead.

This is an article from DZone’s 2022 Kubernetes in Enterprise Trends report.

for more information:

read the report

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