Kubernetes in Docker (KinD) – Cluster Bootstrap Script for Continuous Integration

I have been using Kubernetes in Docker (KinD) for over a year and it’s ideal when you require an ephemeral Kubernetes cluster for local development or testing. My focus with the bootstrap script was to create a Kubernetes cluster where I can easily customise the configuration, choose the required CNI plugin, the Ingress controller or enable Service Mesh if needed, which is especially important in continuous integration pipelines. I will show you two simple examples below of how I use KinD for testing.

I created the ./kind.sh shell script which does what I need to create a cluster in a couple of minutes and apply the configuration.

    • Customise cluster configuration like Kubernetes version, the number of worker nodes, change the service- and pod IP address subnet and a couple of other cluster level configuration.
    • You can choose from different CNI plugins like KinD-CNI (default), Calico and Cilium, or optionally enable the Multus-CNI on top of the CNI plugin.
    • Install the popular known Nginx or Contour Kubernetes ingress controllers. Contour is interesting because it is an Envoy based Ingress controller and can be used for the Kubernetes Gateway API.
    • Enable Istio Service Mesh which is also available as a Gateway API option or install MetalLB, a Kubernetes service type load balancer plugin.
    • Install Operator Lifecycle Manager (OLM) to install Kubernetes community operators from OperatorHub.io.
$ ./kind.sh --help
usage: kind.sh [--name ]
               [--num-workers ]
               [--config-file ]
               [--kubernetes-version ]
               [--cluster-apiaddress ]
               [--cluster-apiport ]
               [--cluster-loglevel ]
               [--cluster-podsubnet ]
               [--cluster-svcsubnet ]

--name                          Name of the KIND cluster
                                DEFAULT: kind
--num-workers                   Number of worker nodes.
                                DEFAULT: 0 worker nodes.
--config-file                   Name of the KIND J2 configuration file.
                                DEFAULT: ./kind.yaml.j2
--kubernetes-version            Flag to specify the Kubernetes version.
                                DEFAULT: Kubernetes v1.21.1
--cluster-apiaddress            Kubernetes API IP address for kind (master).
--cluster-apiport               Kubernetes API port for kind (master).
                                DEFAULT: 6443.
--cluster-loglevel              Log level for kind (master).
                                DEFAULT: 4.
--cluster-podsubnet             Pod subnet IP address range.
--cluster-svcsubnet             Service subnet IP address range.
--disable-default-cni           Flag to disable Kind default CNI - required to install custom cni plugin.
                                DEFAULT: Default CNI used.
--install-calico-cni            Flag to install Calico CNI Components.
                                DEFAULT: Don't install calico cni components.
--install-cilium-cni            Flag to install Cilium CNI Components.
                                DEFAULT: Don't install cilium cni components.
--install-multus-cni            Flag to install Multus CNI Components.
                                DEFAULT: Don't install multus cni components.
--install-istio                 Flag to install Istio Service Mesh Components.
                                DEFAULT: Don't install istio components.
--install-metallb               Flag to install Metal LB Components.
                                DEFAULT: Don't install loadbalancer components.
--install-nginx-ingress         Flag to install Ingress Components - can't be used in combination with istio.
                                DEFAULT: Don't install ingress components.
--install-contour-ingress       Flag to install Ingress Components - can't be used in combination with istio.
                                DEFAULT: Don't install ingress components.
--install-istio-gateway-api     Flag to install Istio Service Mesh Gateway API Components.
                                DEFAULT: Don't install istio components.
--install-contour-gateway-api   Flag to install Ingress Components - can't be used in combination with istio.
                                DEFAULT: Don't install ingress components.
--install-olm                   Flag to install Operator Lifecyle Manager
                                DEFAULT: Don't install olm components.
                                Visit https://operatorhub.io to install available operators
--delete                        Delete Kind cluster.

Based on the options you choose, the script renders the needed KinD config YAML file and creates the clusters locally in a couple of minutes. To install Istio Service Mesh on KinD you also need the Istio profile which you can find together with the bootstrap script in my GitHub Gists.

Let’s look into how I use KinD and the bootstrap script in Jenkins for continuous integration (CI). I have a pipeline which executes the bootstrap script to create the cluster on my Jenkins agent.

For now I kept the configuration very simple and only need the Nginx Ingress controller in this example:

stages {
    stage('Prepare workspace') {
        steps {
            git credentialsId: 'github-ssh', url: '[email protected]:ab7fb36162f39dbed08f7bd90072a3d2.git'

    stage('Create Kind cluster') {
        steps {
            sh '''#!/bin/bash
            bash ./kind.sh --kubernetes-version v1.21.1 \
    stage('Clean-up workspace') {
        steps {
            sh 'rm -rf *'

Log output of the script parameters:

I have written a Go Helloworld application and the Jenkins pipeline which runs the Go unit-tests and builds the container image. It also triggers the build job for the create-kind-cluster pipeline to spin-up the Kubernetes cluster.

stage ('Create Kind cluster') {
    steps {
        build job: 'create-kind-cluster'

It then continues to deploy the newly build Helloworld container image and executes a simple end-to-end ingress test.

I also use this same example for my Go Helloworld Kubernetes operator build pipeline. It builds the Go operator and again triggers the build job to create the KinD cluster. It then continues to deploy the Helloworld operator and applies the Custom Resources, and finishes with a simple end-to-end ingress test.

I hope this is an interesting and useful article. Visit my GitHub Gists to download the KinD bootstrap script.

Deploy OpenShift using Jenkins Pipeline and Terraform

I wanted to make my life a bit easier and created a simple Jenkins pipeline to spin-up the AWS instance and deploy OpenShift. Read my previous article: Deploying OpenShift 3.11 Container Platform on AWS using Terraform. You will see in between steps which require input to stop the pipeline, and that keep the OpenShift cluster running without destroying it directly after installing OpenShift. Also check out my blog post I wrote about running Jenkins in a container with Ansible and Terraform.

The Jenkins pipeline requires a few environment variables for the credentials to access AWS and CloudFlare. You need to create the necessary credentials beforehand and they get loaded when the pipeline starts.

Here are the pipeline steps which are self explanatory:

pipeline {
    agent any
    environment {
        AWS_ACCESS_KEY_ID = credentials('AWS_ACCESS_KEY_ID')
        TF_VAR_email = credentials('TF_VAR_email')
        TF_VAR_token = credentials('TF_VAR_token')
        TF_VAR_domain = credentials('TF_VAR_domain')
        TF_VAR_htpasswd = credentials('TF_VAR_htpasswd')
    stages {
        stage('Prepare workspace') {
            steps {
                sh 'rm -rf *'
                git branch: 'aws-dev', url: 'https://github.com/berndonline/openshift-terraform.git'
                sh 'ssh-keygen -b 2048 -t rsa -f ./helper_scripts/id_rsa -q -N ""'
                sh 'chmod 600 ./helper_scripts/id_rsa'
                sh 'terraform init'
        stage('Run terraform apply') {
            steps {
                input 'Run terraform apply?'
        stage('terraform apply') {
            steps {
                sh 'terraform apply -auto-approve'
        stage('OpenShift Installation') {
            steps {
                sh 'sleep 600'
                sh 'scp -o StrictHostKeyChecking=no -o UserKnownHostsFile=/dev/null -i ./helper_scripts/id_rsa -r ./helper_scripts/id_rsa cen[email protected]$(terraform output bastion):/home/centos/.ssh/'
                sh 'scp -o StrictHostKeyChecking=no -o UserKnownHostsFile=/dev/null -i ./helper_scripts/id_rsa -r ./inventory/ansible-hosts  [email protected]$(terraform output bastion):/home/centos/ansible-hosts'
                sh 'ssh -o StrictHostKeyChecking=no -o UserKnownHostsFile=/dev/null -i ./helper_scripts/id_rsa -l centos $(terraform output bastion) -A "cd /openshift-ansible/ && ansible-playbook ./playbooks/openshift-pre.yml -i ~/ansible-hosts"'
                sh 'ssh -o StrictHostKeyChecking=no -o UserKnownHostsFile=/dev/null -i ./helper_scripts/id_rsa -l centos $(terraform output bastion) -A "cd /openshift-ansible/ && ansible-playbook ./playbooks/openshift-install.yml -i ~/ansible-hosts"'
        stage('Run terraform destroy') {
            steps {
                input 'Run terraform destroy?'
        stage('terraform destroy') {
            steps {
                sh 'terraform destroy -force '

Let’s trigger the pipeline and look at the progress of the different steps.

The first step preparing the workspace is very quick and the pipeline is waiting for an input to run terraform apply:

Just click on proceed to continue:

After the AWS and CloudFlare resources are created with Terraform, it continues with the next step installing OpenShift 3.11 on the AWS instances:

By this point the OpenShift installation is completed.

You can continue and login to the console-paas.. and continue doing your testing on OpenShift.

Terraform not only created all the AWS resources it also configured the necessary CNAME on CloudFlare DNS to point to the AWS load balancers.

Once you are finished with your OpenShift testing you can go back into Jenkins pipeline and commit to destroy the environment again:

Running terraform destroy:

The pipeline completed successfully:

I hope this was in interesting post and let me know if you like it and want to see more of these. I am planning some improvements to integrate a validation step in the pipeline, to create a project and build, and deploy container on OpenShift automatically.

Please share your feedback and leave a comment.

Build Jenkins Container with Terraform and Ansible

I thought it might be interesting to show how to build a Docker container running Jenkins and tools like Terraform and Ansible. I am planning to use a Jenkins pipeline to deploy my OpenShift 3.11 example on AWS using Terraform and Ansible but more about this in the next post.

I am using the source Dockerfile from Jenkins and modified it, and added Ansible and Terraform: https://github.com/jenkinsci/docker. Below you see a few variables you might need to change depending on the version you are trying to use or where to place the volume mount. Have a look here for the latest Jenkins version: https://updates.jenkins-ci.org/download/war/.

Here is my Dockerfile:

ARG JENKINS_HOME=/var/jenkins_home
ARG JENKINS_SHA=a4335cc626c1f64da61a20174af654283d171b255a928bbacb6402a315e213d7

Let’s start and clone my Jenkins Docker repository  and run docker build:

git clone https://github.com/berndonline/jenkins-docker.git && cd ./jenkins-docker/
docker build -t berndonline/jenkins .

The docker build will take a few minutes, just wait and look out for error you might have with the build:

[email protected]:~/jenkins-docker$ docker build -t berndonline/jenkins .
Sending build context to Docker daemon  141.3kB
Step 1/51 : FROM openjdk:8-jdk
8-jdk: Pulling from library/openjdk
54f7e8ac135a: Pull complete
d6341e30912f: Pull complete
087a57faf949: Pull complete
5d71636fb824: Pull complete
9da6b28682cf: Pull complete
203f1094a1e2: Pull complete
ee38d9f85cf6: Pull complete
7f692fae02b6: Pull complete
eaa976dc543c: Pull complete
Digest: sha256:94bbc3357f995dd37986d8da0f079a9cd4b99969a3c729bad90f92782853dea7
Status: Downloaded newer image for openjdk:8-jdk
 ---> c14ba9d23b3a
Step 2/51 : USER root
 ---> Running in c78f75ca3d5a
Removing intermediate container c78f75ca3d5a
 ---> f2c6bb7538ea
Step 3/51 : RUN apt-get update && apt-get install -y git curl && rm -rf /var/lib/apt/lists/*
 ---> Running in 4cc857e12f50
Ign:1 http://deb.debian.org/debian stretch InRelease
Get:2 http://security.debian.org/debian-security stretch/updates InRelease [94.3 kB]
Get:3 http://deb.debian.org/debian stretch-updates InRelease [91.0 kB]
Get:4 http://deb.debian.org/debian stretch Release [118 kB]
Get:5 http://security.debian.org/debian-security stretch/updates/main amd64 Packages [459 kB]
Get:6 http://deb.debian.org/debian stretch Release.gpg [2434 B]
Get:7 http://deb.debian.org/debian stretch-updates/main amd64 Packages [5152 B]
Get:8 http://deb.debian.org/debian stretch/main amd64 Packages [7089 kB]
Fetched 7859 kB in 1s (5540 kB/s)
Reading package lists...
Reading package lists...
Building dependency tree...


Step 49/51 : ENTRYPOINT ["/sbin/tini", "--", "/usr/local/bin/jenkins.sh"]
 ---> Running in 28da7c4bf90a
Removing intermediate container 28da7c4bf90a
 ---> f380f1a6f06f
Step 50/51 : COPY plugins.sh /usr/local/bin/plugins.sh
 ---> 82871f0df0dc
Step 51/51 : COPY install-plugins.sh /usr/local/bin/install-plugins.sh
 ---> feea9853af70
Successfully built feea9853af70
Successfully tagged berndonline/jenkins:latest
[email protected]:~/jenkins-docker$

The Docker container is successfully build:

[email protected]:~/jenkins-docker$ docker images
REPOSITORY                  TAG                 IMAGE ID            CREATED             SIZE
berndonline/jenkins         latest              cd1742c317fa        6 days ago          1.28GB

Let’s start the Docker container:

docker run -d -v /var/jenkins_home:/var/jenkins_home -p 32771:8080 -p 32770:50000 berndonline/jenkins

Quick check that the container is successfully created:

[email protected]:~/jenkins-docker$ docker ps
CONTAINER ID        IMAGE                 COMMAND                  CREATED             STATUS              PORTS                                               NAMES
7073fa9c0cd4        berndonline/jenkins   "/sbin/tini -- /usr/…"   5 days ago          Up 7 seconds>8080/tcp,>50000/tcp   jenkins

Afterwards you can connect to http://<your-ip-address>:32771/ and do the initial Jenkins configuration, like changing admin password and install needed plugins. I recommend putting an Nginx reverse proxy with SSL infront to secure Jenkins properly.

So what about updates or changing the configuration? – Pretty easy; because we are using a Docker bind mount to /var/jenkins_home/, all the Jenkins related data is stored on the local file system of your server and you can re-create or re-build the container at anytime.

I hope you like this article about how to create your down Jenkins Docker container. In my next post I will create a very simple Jenkins pipeline to deploy OpenShift 3.11 on AWS using Terraform.

Please share your feedback and leave a comment.

Getting started with Jenkins for Network Automation

As I have mentioned my previous post about Getting started with Gitlab-CI for Network Automation, Jenkins is another continuous integration pipelining tool you can use for network automation. Have a look about how to install Jenkins: https://wiki.jenkins.io/display/JENKINS/Installing+Jenkins+on+Ubuntu

To use the Jenkins with Vagrant and KVM (libvirt) there are a few changes needed on the linux server similar with the Gitlab-Runner. The Jenkins user account needs to be able to control KVM and you need to install the vagrant-libvirt plugin:

usermod -aG libvirtd jenkins
sudo su jenkins
vagrant plugin install vagrant-libvirt

Optional: you may need to copy custom Vagrant boxes into the users vagrant folder ‘/var/lib/jenkins/.vagrant.d/boxes/*’. Note that the Jenkins home directory is not located under /home.

Now lets start configuring a Jenkins CI-pipeline, click on ‘New item’:

This creates an empty pipeline where you need to add the different stages  of what needs to be executed:

Below is an example Jenkins pipeline script which is very similar to the Gitlab-CI pipeline I have used with my Cumulus Linux Lab in the past.

pipeline {
    agent any
    stages {
        stage('Clean and prep workspace') {
            steps {
                sh 'rm -r *'
                git 'https://github.com/berndonline/cumulus-lab-provision'
                sh 'git clone --origin master https://github.com/berndonline/cumulus-lab-vagrant'
        stage('Validate Ansible') {
            steps {
                sh 'bash ./linter.sh'
        stage('Staging') {
            steps {
                sh 'cd ./cumulus-lab-vagrant/ && ./vagrant_create.sh'
                sh 'cd ./cumulus-lab-vagrant/ && bash ../staging.sh'
        stage('Deploy production approval') {
            steps {
                input 'Deploy to prod?'
        stage('Production') {
            steps {
                sh 'cd ./cumulus-lab-vagrant/ && ./vagrant_create.sh'
                sh 'cd ./cumulus-lab-vagrant/ && bash ../production.sh'

Let’s run the build pipeline:

The stages get executed one by one and, as you can see below, the production stage has an manual approval build-in that nothing gets deployed to production without someone to approve before, for a controlled production deployment:

Finished pipeline:

This is just a simple example of a network automation pipeline, this can of course be more complex if needed. It should just help you a bit on how to start using Jenkins for network automation.

Please share your feedback and leave a comment.