The kubernetes-ci-cd project is Kenzan's crossword puzzle application that runs as several containers in Kubernetes (we call it the Kr8sswordz Puzzle). It showcases Kubernetes features like spinning up multiple pods and running a load test at scale. It also features Jenkins running on its own a container and a JenkinsFile script to demonstrate how Kubernetes can be integrated into a full CI/CD pipeline.
To get it up and running, see the following week-by-week Linux.com blog posts, or simply follow the directions below.
To generate this readme: node readme.js
- Install VirtualBox
https://www.virtualbox.org/wiki/Downloads
- Install the latest versions of Docker, Minikube, and Kubectl
https://docs.docker.com/docker-for-mac/install/ https://github.com/kubernetes/minikube/releases https://kubernetes.io/docs/tasks/tools/install-kubectl/
- Install Helm
curl https://raw.githubusercontent.com/kubernetes/helm/master/scripts/get > get_helm.sh; chmod 700 get_helm.sh; ./get_helm.sh
- Clone this repository
- To ensure you are starting with a clean slate, delete any previous minikube contexts.
minikube stop; minikube delete; sudo rm -rf ~/.minikube; sudo rm -rf ~/.kube
Start up the Kubernetes cluster with Minikube, giving it some extra resources.
minikube start --memory 8000 --cpus 2 --kubernetes-version v1.11.0
Enable the Minikube add-ons Heapster and Ingress.
minikube addons enable heapster; minikube addons enable ingress
View the Minikube Dashboard, a web UI for managing deployments.
minikube service kubernetes-dashboard --namespace kube-system
Deploy the public nginx image from DockerHub into a pod. Nginx is an open source web server that will automatically download from Docker Hub if it’s not available locally.
kubectl run nginx --image nginx --port 80
Create a K8s Service for the deployment. This will expose the nginx pod so you can access it with a web browser.
kubectl expose deployment nginx --type NodePort --port 80
Launch a web browser to test the service. The nginx welcome page displays, which means the service is up and running.
minikube service nginx
Delete the nginx deployment and service you created.
kubectl delete service nginx
kubectl delete deployment nginx
Set up the cluster registry by applying a .yaml manifest file.
kubectl apply -f manifests/registry.yaml
Wait for the registry to finish deploying using the following command. Note that this may take several minutes.
kubectl rollout status deployments/registry
View the registry user interface in a web browser.
minikube service registry-ui
Let’s make a change to an HTML file in the cloned project. Open the /applications/hello-kenzan/index.html file in your favorite text editor. (For example, you could use nano by running the command 'nano applications/hello-kenzan/index.html' in a separate terminal). Change some text inside one of the <p> tags. For example, change “Hello from Kenzan!” to “Hello from Me!”. Save the file.
Now let’s build an image, giving it a special name that points to our local cluster registry.
docker build -t 127.0.0.1:30400/hello-kenzan:latest -f applications/hello-kenzan/Dockerfile applications/hello-kenzan
We’ve built the image, but before we can push it to the registry, we need to set up a temporary proxy. By default the Docker client can only push to HTTP (not HTTPS) via localhost. To work around this, we’ll set up a Docker container that listens on 127.0.0.1:30400 and forwards to our cluster. First, build the image for our proxy container.
docker build -t socat-registry -f applications/socat/Dockerfile applications/socat
Now run the proxy container from the newly created image. (Note that you may see some errors; this is normal as the commands are first making sure there are no previous instances running.)
docker stop socat-registry; docker rm socat-registry; docker run -d -e "REG_IP=`minikube ip`" -e "REG_PORT=30400" --name socat-registry -p 30400:5000 socat-registry
With our proxy container up and running, we can now push our hello-kenzan image to the local repository.
docker push 127.0.0.1:30400/hello-kenzan:latest
The proxy’s work is done, so you can go ahead and stop it.
docker stop socat-registry
With the image in our cluster registry, the last thing to do is apply the manifest to create and deploy the hello-kenzan pod based on the image.
kubectl apply -f applications/hello-kenzan/k8s/manual-deployment.yaml
Launch a web browser and view the service.
minikube service hello-kenzan
Delete the hello-kenzan deployment and service you created. We are going to keep the registry deployment in our cluster as we will need it for the next few parts in our series.
kubectl delete service hello-kenzan
kubectl delete deployment hello-kenzan
First, let's build the Jenkins Docker image we'll use in our Kubernetes cluster.
docker build -t 127.0.0.1:30400/jenkins:latest -f applications/jenkins/Dockerfile applications/jenkins
Once again we'll need to set up the Socat Registry proxy container to push images, so let's build it. Feel free to skip this step in case the socat-registry image already exists from Part 1 (to check, run docker images).
docker build -t socat-registry -f applications/socat/Dockerfile applications/socat
Run the proxy container from the image.
docker stop socat-registry; docker rm socat-registry; docker run -d -e "REG_IP=`minikube ip`" -e "REG_PORT=30400" --name socat-registry -p 30400:5000 socat-registry
With our proxy container up and running, we can now push our Jenkins image to the local repository.
docker push 127.0.0.1:30400/jenkins:latest
The proxy’s work is done, so you can go ahead and stop it.
docker stop socat-registry
Deploy Jenkins, which we’ll use to create our automated CI/CD pipeline. It will take the pod a minute or two to roll out.
kubectl apply -f manifests/jenkins.yaml; kubectl rollout status deployment/jenkins
Open the Jenkins UI in a web browser.
minikube service jenkins
Display the Jenkins admin password with the following command, and right-click to copy it.
kubectl exec -it `kubectl get pods --selector=app=jenkins --output=jsonpath={.items..metadata.name}` cat /var/jenkins_home/secrets/initialAdminPassword
Switch back to the Jenkins UI. Paste the Jenkins admin password in the box and click Continue. Click Install suggested plugins. Plugins have actually been pre-downloaded during the Jenkins image build, so this step should finish fairly quickly.
Create an admin user and credentials, and click Save and Continue. (Make sure to remember these credentials as you will need them for repeated logins.) On the Instance Configuration page, click Save and Finish. On the next page, click Restart (if it appears to hang for some time on restarting, you may have to refresh the browser window). Login to Jenkins.
Before we create a pipeline, we first need to provision the Kubernetes Continuous Deploy plugin with a kubeconfig file that will allow access to our Kubernetes cluster. In Jenkins on the left, click on Credentials, select the Jenkins store, then Global credentials (unrestricted), and Add Credentials on the left menu.
The following values must be entered precisely as indicated:
- Kind:
Kubernetes configuration (kubeconfig) - ID:
kenzan_kubeconfig - Kubeconfig:
From a file on the Jenkins master - specify the file path:
/var/jenkins_home/.kube/config
Finally click Ok.
We now want to create a new pipeline for use with our Hello-Kenzan app. Back on Jenkins home, on the left, click New Item. Enter the item name as "Hello-Kenzan Pipeline", select Pipeline, and click OK.
Under the Pipeline section at the bottom, change the Definition to be Pipeline script from SCM.
Change the SCM to Git. Change the Repository URL to be the URL of your forked Git repository, such as https://github.com/[GIT USERNAME]/kubernetes-ci-cd. Click Save. On the left, click Build Now to run the new pipeline.
After all pipeline stages are colored green as complete, view the Hello-Kenzan application.
minikube service hello-kenzan
Push a change to your fork. Run the job again. View the changes.
minikube service hello-kenzan
Initialize Helm. This will install Tiller (Helm's server) into our Kubernetes cluster.
helm init --wait --debug; kubectl rollout status deploy/tiller-deploy -n kube-system
We will deploy the etcd operator onto the cluster using a Helm Chart.
helm install stable/etcd-operator --version 0.8.0 --name etcd-operator --debug --wait
Deploy the etcd cluster and K8s Services for accessing the cluster.
kubectl create -f manifests/etcd-cluster.yamlkubectl create -f manifests/etcd-service.yaml
The crossword application is a multi-tier application whose services depend on each other. We will create three K8s Services so that the applications can communicate with one another.
kubectl apply -f manifests/all-services.yaml
Now we're going to walk through an initial build of the monitor-scale application.
docker build -t 127.0.0.1:30400/monitor-scale:`git rev-parse --short HEAD` -f applications/monitor-scale/Dockerfile applications/monitor-scale
Once again we'll need to set up the Socat Registry proxy container to push the monitor-scale image to our registry, so let's build it. Feel free to skip this step in case the socat-registry image already exists from Part 2 (to check, run docker images).
docker build -t socat-registry -f applications/socat/Dockerfile applications/socat
Run the proxy container from the newly created image.
docker stop socat-registry; docker rm socat-registry; docker run -d -e "REG_IP=`minikube ip`" -e "REG_PORT=30400" --name socat-registry -p 30400:5000 socat-registry
Push the monitor-scale image to the registry.
docker push 127.0.0.1:30400/monitor-scale:`git rev-parse --short HEAD`
The proxy’s work is done, so go ahead and stop it.
docker stop socat-registry
Open the registry UI and verify that the monitor-scale image is in our local registry.
minikube service registry-ui
Monitor-scale has the functionality to let us scale our puzzle app up and down through the Kr8sswordz UI, therefore we'll need to do some RBAC work in order to provide monitor-scale with the proper rights.
kubectl apply -f manifests/monitor-scale-serviceaccount.yaml
Create the monitor-scale deployment and the Ingress defining the hostname by which this service will be accessible to the other services.
sed 's#127.0.0.1:30400/monitor-scale:$BUILD_TAG#127.0.0.1:30400/monitor-scale:'`git rev-parse --short HEAD`'#' applications/monitor-scale/k8s/deployment.yaml | kubectl apply -f -
Wait for the monitor-scale deployment to finish.
kubectl rollout status deployment/monitor-scale
View pods to see the monitor-scale pod running.
kubectl get pods
View services to see the monitor-scale service.
kubectl get services
View ingress rules to see the monitor-scale ingress rule.
kubectl get ingress
View deployments to see the monitor-scale deployment.
kubectl get deployments
We will run a script to bootstrap the puzzle and mongo services, creating Docker images and storing them in the local registry. The puzzle.sh script runs through the same build, proxy, push, and deploy steps we just ran through manually for both services.
scripts/puzzle.sh
Check to see if the puzzle and mongo services have been deployed.
kubectl rollout status deployment/puzzlekubectl rollout status deployment/mongo
Bootstrap the kr8sswordz frontend web application. This script follows the same build proxy, push, and deploy steps that the other services followed.
scripts/kr8sswordz-pages.sh
Check to see if the frontend has been deployed.
kubectl rollout status deployment/kr8sswordz
Check to see that all the pods are running.
kubectl get pods
Start the web application in your default browser. You may have to refresh your browser so that the puzzle appears properly.
minikube service kr8sswordz
Enter the following command to open the Jenkins UI in a web browser. Log in to Jenkins using the username and password you previously set up.
minikube service jenkins
We’ll want to create a new pipeline for the puzzle service that we previously deployed. On the left in Jenkins, click New Item.
Enter the item name as "Puzzle-Service", click Pipeline, and click OK.
Under the Build Triggers section, select Poll SCM. For the Schedule, enter the the string H/5 * * * * which will poll the Git repo every 5 minutes for changes.
In the Pipeline section, change the Definition to "Pipeline script from SCM". Set the SCM property to GIT. Set the Repository URL to your forked repo (created in Part 2), such as https://github.com/[GIT USERNAME]/kubernetes-ci-cd.git. Set the Script Path to applications/puzzle/Jenkinsfile
When you are finished, click Save. On the left, click Build Now to run the new pipeline. This will rebuild the image from the registry, and redeploy the puzzle pod. You should see it successfully run through the build, push, and deploy steps in a few minutes.
View the Kr8sswordz application.
minikube service kr8sswordz
Spin up several instances of the puzzle service by moving the slider to the right and clicking Scale. For reference, click on the Submit button, noting that the white hit does not register on the puzzle services.
Edit applications/puzzle/common/models/crossword.js in your favorite text editor (for example, you can use nano by running the command 'nano applications/puzzle/common/models/crossword.js' in a separate terminal). You'll see a commented section on lines 42-43 that indicates to uncomment a specific line. Uncomment line 43 by deleting the forward slashes and save the file.
Commit and push the change to your forked Git repo.
In Jenkins, open up the Puzzle-Service pipeline and wait until it triggers a build. It should trigger every 5 minutes.
After it triggers, observe how the puzzle services disappear in the Kr8sswordz Puzzle app, and how new ones take their place.
Try clicking Submit to test that hits now register as white.
If you need to walk through the steps in the tutorial again (or more quickly), we’ve provided npm scripts that automate running the same commands in the separate parts of the Tutorial.
- Install NodeJS.
- Install the scripts.
cd ~/kubernetes-ci-cdnpm install
Begin the desired section:
npm run part1npm run part2npm run part3npm run part4
Copyright 2017 Kenzan, LLC http://kenzan.com
Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.