Building Docker Images in Kubernetes with Kaniko for Jenkins CI

Kaniko in Kubernetes with Jenkins

The Case for Kaniko

If we need to build a Docker image inside a k8s cluster, Kaniko is the tool for the job.

I tried using k8s agent executers in Jenkins on my k3s cluster running on Linux containers. Since I’m running containerd as the container runtime in k3s, and did not want to run a priviledged container for building the images, I did some research on the subject, which made me stumble upon Kaniko¹.

Kaniko operates without relying on a Docker daemon, executing each command in a Dockerfile entirely in userspace. This allows for building container images in environments where running a Docker daemon is impractical or insecure, such as a standard Kubernetes cluster.

Kaniko for Jenkins CI

Once we set up the k8s agent executers in Jenkins², we can include the Kaniko related specs inside the Jenkins k8s agent config, and use them in pipeline steps.

pipeline {
  agent {
    kubernetes {
      label 'example-kaniko-volumes'
      yaml """
kind: Pod
metadata:
  name: kaniko
spec:
  containers:
  - name: jnlp
    workingDir: /tmp/jenkins
  - name: kaniko
    workingDir: /tmp/jenkins
    image: gcr.io/kaniko-project/executor:debug
    imagePullPolicy: Always
    command:
    - /busybox/cat
    tty: true
    volumeMounts:
    - name: jenkins-docker-cfg
      mountPath: /kaniko/.docker
  volumes:
  - name: jenkins-docker-cfg
    projected:
      sources:
      - secret:
        name: docker-credentials
        items:
        - key: .dockerconfigjson
          path: config.json
"""
    }
  }
}

Please refer https://docs.cloudbees.com/docs/cloudbees-ci-kb/latest/cloudbees-ci-on-modern-cloud-platforms/what-you-need-to-know-when-using-kaniko-from-kubernetes-jenkins-agents in case you encounter issues.

Also check out https://github.com/jenkinsci/kubernetes-plugin/blob/master/examples/kaniko.groovy.