How DevOps, Containers, and Kubernetes Transform Modern Software Delivery

In recent years, with the rise of containers and Kubernetes, the concept of DevOps has become widely adopted. This article explains the origin of DevOps, its relationship with containers/Kubernetes, and the technical implementation, illustrated with a hands‑on experiment.

What is DevOps

DevOps combines Development (Dev) and Operations (Ops) to break down the wall between developers and operations teams, enabling a unified, faster delivery process.

From Waterfall to Agile to DevOps

The article reviews the history of software development, from waterfall to agile, highlighting the limitations of rigid processes and the need for more flexible, iterative approaches. Agile principles emerged in 2001, emphasizing rapid response to change. Building on agile, the evolution continues: Agile → Continuous Integration → Continuous Delivery → Continuous Deployment → DevOps.

Continuous Integration (CI) requires all code changes to pass automated tests before merging. Continuous Delivery (CD) frequently delivers new builds for review, and Continuous Deployment automatically deploys successful builds. DevOps ties these stages together, automating the entire flow from code commit to production.

Technical Implementation of DevOps

1. Standard Deliverables

To achieve true DevOps, a standard deliverable that includes the operating system, runtime, and application is needed, enabling “build once, run everywhere.”

2. Container Orchestration Platform

Kubernetes, introduced in 2014, provides a unified scheduler for containers, supporting persistent storage and virtual networking, making containers enterprise‑ready.

3. DevOps Toolchain

Typical open‑source tools include:

Kubernetes cluster (Docker + Kubernetes)

Gogs – a self‑hosted Git service

Jenkins (with Jenkins Slave Pods) – CI server

Nexus – artifact repository

SonarQube – code quality analysis

Jenkins Pipeline Workflow

The complete DevOps flow is orchestrated by a Jenkins Pipeline defined in a Jenkinsfile. The pipeline stages are:

pipeline {</code><code>  agent {</code><code>    label 'maven'</code><code>  }</code><code>  stages {</code><code>    stage('Build App') {</code><code>      steps {</code><code>        git branch: 'eap-7', url: 'http://gogs:3000/gogs/openshift-tasks.git'</code><code>        script {</code><code>          def pom = readMavenPom file: 'pom.xml'</code><code>          version = pom.version</code><code>        }</code><code>        sh "${mvnCmd} install -DskipTests=true"</code><code>      }</code><code>    }</code><code>    stage('Test') {</code><code>      steps {</code><code>        sh "${mvnCmd} test"</code><code>        step([$class: 'JUnitResultArchiver', testResults: '**/target/surefire-reports/TEST-*.xml'])</code><code>      }</code><code>    }</code><code>    stage('Code Analysis') {</code><code>      steps {</code><code>        sh "${mvnCmd} sonar:sonar -Dsonar.host.url=http://sonarqube:9000 -DskipTests=true"</code><code>      }</code><code>    }</code><code>    stage('Archive App') {</code><code>      steps {</code><code>        sh "${mvnCmd} deploy -DskipTests=true -P nexus3"</code><code>      }</code><code>    }</code><code>    stage('Build Image') {</code><code>      steps {</code><code>        sh "rm -rf oc-build && mkdir -p oc-build/deployments"</code><code>        sh "cp target/tasks.war oc-build/deployments/ROOT.war"</code><code>      }</code><code>    }</code><code>    stage('Promote to STAGE?') {</code><code>      steps {</code><code>        timeout(time:15, unit:'MINUTES') {</code><code>          input message: "Promote to STAGE?", ok: "Promote"</code><code>        }</code><code>      }</code><code>    }</code><code>  }</code><code>}

The pipeline pulls source code from Gogs, builds the application with Maven, runs unit tests, performs SonarQube analysis, archives the artifact in Nexus, builds a Docker image, deploys to a development namespace, and after manual approval promotes the image to a staging namespace.

Result

After the pipeline completes, the application can be accessed in both the dev and stage namespaces, demonstrating a fully automated DevOps workflow powered by containers and Kubernetes.

Through this article, readers gain a solid understanding of DevOps concepts, the role of containers/Kubernetes, and a practical example of implementing a CI/CD pipeline.