Rehosting spring-petclinic java application to SUSE Container and Application Platform

This repository hosts the scripts file used as demonstration in SUSECON Digital 2020 Session [DEV-1124].

In this demo, we will check out the source code of a spring-based java application petclinic and walk you through how to containerize and rehost it into SUSE CaaS Platform (kubernetes) and SUSE Cloud Application Platform (cloud foundry).

What do I need to run this demo?

You will need the following to run this demo:

• A Linux distro (tested with SLES15SP1) with git, docker, kubectl and cf-cli installed.
• Free account for Docker Hub (container registry used in this demo)
• Access to a SUSE CaaS Platform cluster
• Access to a SUSE Cloud Application Platform - sign up a free account SUSE CAP Sandbox

Porting the java app to SUSE CaaS Platform

This section guides you the steps needed to containerize and deploy the petclinic java app to SUSE CaaS Platform.

Step 1 - Build the SLES15SP1 based openjdk11 image

Run the script below to build a SLES15SP1 based openjdk docker image. It assumes you build this with a SLES15SP1 linux host.

./build-openjdk11.sh

Tag the docker image and push to docker hub

docker images
docker tag susesamples/sles15sp1-openjdk11:latest susesamples/sles15sp1-openjdk11:11.0.7
docker login
docker push susesamples/sles15sp1-openjdk11:11.0.7

Step 2 - Containerize the petclinic java app

Run the script below to download petclinic's source code and containerize it with a multi-stage docker build file.

./build-spring-petclinic.sh

Tag the docker image and push to docker hub

docker images
docker push susesamples/sles15sp1-spring-petclinic:2.2.0

Step 3 - Ensure accessible to SUSE CaaS Platform

Run the kubectl command below to ensure you have access to a SUSE CaaS Platform.

Example:

$ kubectl get node -o wide
NAME       STATUS     ROLES    AGE    VERSION   INTERNAL-IP    EXTERNAL-IP   OS-IMAGE                              KERNEL-VERSION           CONTAINER-RUNTIME
caasp-m1   Ready      master   187d   v1.17.4   192.168.0.32   <none>        SUSE Linux Enterprise Server 15 SP1   4.12.14-197.34-default   cri-o://1.16.1
caasp-m2   Ready      master   186d   v1.17.4   192.168.0.33   <none>        SUSE Linux Enterprise Server 15 SP1   4.12.14-197.34-default   cri-o://1.16.1
caasp-m3   Ready      master   187d   v1.17.4   192.168.0.34   <none>        SUSE Linux Enterprise Server 15 SP1   4.12.14-197.34-default   cri-o://1.16.1
caasp-w4   Ready      worker   187d   v1.17.4   192.168.0.38   <none>        SUSE Linux Enterprise Server 15 SP1   4.12.14-197.34-default   cri-o://1.16.1
caasp-w5   Ready      worker   187d   v1.17.4   192.168.0.39   <none>        SUSE Linux Enterprise Server 15 SP1   4.12.14-197.34-default   cri-o://1.16.1
caasp-w6   Ready      worker   120d   v1.17.4   192.168.0.40   <none>        SUSE Linux Enterprise Server 15 SP1   4.12.14-197.34-default   cri-o://1.16.1
caasp-w7   NotReady   worker   120d   v1.17.4   192.168.0.41   <none>        SUSE Linux Enterprise Server 15 SP1   4.12.14-197.34-default   cri-o://1.16.1

Step 4 - Define a new namespace for petclinic app

$ kubectl create ns susecon

Step 6 - Store docker hub login credential in SUSE CaaS Platform

Since the petclinic image stored in dockerhub which requires authentication to access to it, we need to pass the docker hub credential to SUSE CaaSP to use. Specifically, we will let this petclinic namespace to use exclusively.

Login to docker hub first in your linux terminal session. This will store your credential in $HOME/.docker/config.json file.

docker login

Then, create a kubernetes secret object to store your docker hub credential in the susecon namespace.

kubectl create secret generic docker-cred \
    --from-file=.dockerconfigjson=$HOME/.docker/config.json \
    --namespace susecon \
    --type=kubernetes.io/dockerconfigjson

Associate the docker-cred to default service account in susecon namespace.

kubectl patch serviceaccount default -p '{"imagePullSecrets": [{"name": "docker-cred"}]}' -n susecon

Step 7 - Deploy the petclinic container image into SUSE CaaS Platform

Create a deployment resource for petclinic container image.

kubectl create deployment petclinic \
  --image=susesamples/sles15sp1-spring-petclinic:2.2.0 \
  --namespace=susecon

Expose petclinic to be accessible with nodeport.

kubectl expose deployment/petclinic -n susecon --type="NodePort" --port 8080

kubectl get svc -n susecon
NAME        TYPE       CLUSTER-IP    EXTERNAL-IP   PORT(S)          AGE
petclinic   NodePort   10.99.3.184   <none>        8080:31219/TCP   30h

In this example, the petclinic app is exposed with high port number 31219. It can be accessible with any worker node IP address which can be found with kubectl get node -o wide command.

Step 8 - Navigate to the petclinic web url

In this example, you can navigate to http://192.168.0.38:31219 where .38 is an IP address of a worker node and 31219 is the port exposed by NodePort. This is the petclinic app url. Simple and done!

Porting the java app to SUSE Cloud Application Platform

Step 1 - Check out the source code of the spring-petclinic java application

If you haven't check out the source code from github, please check it out now with the command below.

git clone 

Step 2 - Build a fat-jar package of the petclinic app with container-based maven tool

Run the container based maven tool to build the jar package of the petclinic locally.

docker run -it --rm --name petclinic-maven \
 -v "$PWD":/usr/src/app \
 -v "$HOME"/.m2:/root/.m2 \
 -w /usr/src/app maven:3-jdk-8-slim \
  mvn clean package

Check the output of the jar file:

ls -l target/*.jar

Step 3 - Login to SUSE Cloud Application Platform with CLI

Set SUSE CAP Sand Box as API endpoint, login and then create a new space susecon for hosting petclinic app

cf api https://api.cap.explore.suse.dev
cf login
cf create-space susecon
cf target -s susecon

Step 4 - Push the code to SUSE Cloud Application Platform

Run the command below to push the code to SUSE CAP

cf push petclinic -p target/spring-petclinic-2.3.0.BUILD-SNAPSHOT.jar

Step 5 - Navigate to the petclinic web url

List the apps deployed

$ cf apps
Getting apps in ...
OK

name        requested state   instances   memory   disk   urls
petclinic   started           1/1         1G       1G     petclinic.cap.explore.suse.dev

The web url is https://petclinic.cap.explore.suse.dev

Step 6 - Explore Stratos

Navigate to SUSE CAP Sandbox (https://stratos.cap.explore.suse.dev)