Note: This a demo project for Eclipse JKube for a blog. You can find full blog here: Introduction to Eclipse JKube Kubenretes & OpenShift Gradle Plugins
This is a simple random number generation application which just generates a hello string on / endpoint. It just
demonstrates usage of Eclipse JKube: https://github.com/eclipse/jkube
Just run gradle clean build
Do java -jar build/libs/eclipse-jkube-demo-project-gradle-0.0.1-SNAPSHOT.jar
After spring boot initializes, just do a curl localhost:8080/ to check endpoint.
In order to build docker image of your application, you just have to make sure your docker deamon is running. If using
minikube, you can simply do eval $(minikube docker-env) to expose docker deamon running inside minikube vm. Now in
order to build simply issue:
gradle k8sBuild
Make sure you have your image name configured with respect to the registry you want to push to. In this case I would be pushing
it to Docker Hub. I have added this property in gradle.properties file which overrides name of the Image being used:
jkube.generator.name = quay.io/rohankanojia/eclipse-jkube-demo-project-gradle:1.0.0I have my registry setting being defined in my ~/.docker/config.json by doing docker login:
eclipse-jkube-demo-project-gradle : $ docker login quay.io
Username: rohankanojia
Password:
WARNING! Your password will be stored unencrypted in /home/rokumar/.docker/config.json.
Configure a credential helper to remove this warning. See
https://docs.docker.com/engine/reference/commandline/login/#credentials-store
Login Succeededgradle k8sPush
Once pushed you can see your image being pushed to Docker registry like this:
Once your image is built, you need to generate Kubernetes resource manifests for your Deployments, Service etc. To do it using Eclipse JKube Kubernetes Gradle Plugin just do:
gradle k8sResource
In order to deploy these generated manifests onto Kubernetes, just issue:
gradle k8sApply
You'd observe they would be applied onto your Kubernetes Cluster. Right now Eclipse JKube has created a Deployment and a Service based on opinionated defaults. By default Service created is of type ClusterIP, which means it's only accessible from within the Kubernetes Cluster. That's why you see there is an ssh into minikube for accessing endpoint. If you want to access your application from outside the cluster you have to tell plugin to create service of type NodePort by specifying this property:
jkube.enricher.jkube-service.type = NodePortAfter that you can notice that gradle k8sResource goal would generate Service of type NodePort. Here is how it would look like in action:
If you want to un-deploy, we have this goal to delete all resources applied.
gradle k8sUndeploy
Red Hat OpenShift is Red Hat's official distribution of Kubernetes which empowers developers to innovate and ship faster with the leading hybrid cloud, enterprise container platform.
We would also be taking a look into how Eclipse JKube OpenShift Gradle Plugin can be used to deploy this random generator application on top of Red Hat OpenShift.
You can add it as a dependency in your project's pom.xml like this:
plugins {
id 'org.eclipse.jkube.openshift' version '1.5.1'
}It's already added inside this project's build.gradle. So let's start by logging into our OpenShift cluster:
~/work/repos/eclipse-jkube-demo-project : $ oc login https://api.rh-idev.openshift.com --token=mytoken
Logged into "https://api.rh-idev.openshift.com:443" as "rohanKanojia" using the token provided.
You have one project on this server: "rokumar"
Using project "rokumar".
OpenShift has a really nice Source-to-image(S2I) framework which eases writing images by just providing application source code as an input. Note that you would need to comment out jkube.generator.name property that we added during docker build in order to use this. OpenShift Gradle Plugin relies on this for build process. Here is how it would look:
gradle ocBuild
Once build is complete you can see BuildConfig being created, OpenShift build process takes care of building and pushing the image to OpenShift's internal container registry:
oc: Pushing image image-registry.openshift-image-registry.svc:5000/rokumar-dev/eclipse-jkube-demo-project-gradle:1.0.0 ...
oc: Getting image source signatures
oc: Copying blob sha256:3d50bd3a6769cbedb4b4181d75f5a339038825ec12979cff2ec2a210b24c73e4
oc: Copying blob sha256:27e66e775ba36a6ac17cc1cbd8744331133be6d2ae31b0787e9ab79f04cfe6bd
oc: Copying blob sha256:46cdcde062b27f6c24775848f60eeb6a7216a98d4d6d7617927f5024fc8edfc3
oc: Copying blob sha256:c2c17d84f25a8380da8196e4173249e5324e4f653231b00d2e95a6efaac5687a
oc: Copying config sha256:1e7735bc4ce7fa00373a63d655c8f0620fc35caaa3ad97277848d0a5e2724795
oc: Writing manifest to image destination
oc: Storing signatures
oc: Successfully pushed image-registry.openshift-image-registry.svc:5000/rokumar-dev/eclipse-jkube-demo-project-gradle@sha256:9a4310fd2fda78a416e139db2da0e0868e955b7a492f6a849952fb4e6e3093b4
oc: Push successful
oc: Build eclipse-jkube-demo-project-gradle-s2i-2 in status Complete
oc: Found tag on ImageStream eclipse-jkube-demo-project-gradle tag: sha256:9a4310fd2fda78a416e139db2da0e0868e955b7a492f6a849952fb4e6e3093b4:ocBuild
oc: ImageStream eclipse-jkube-demo-project-gradle written to /home/rokumar/Downloads/eclipse-jkube-demo-project-gradle/build/eclipse-jkube-demo-project-gradle-is.yml
BUILD SUCCESSFUL in 1m 25s
1 actionable task: 1 executed
eclipse-jkube-demo-project-gradle : $
eclipse-jkube-demo-project-gradle : $ oc get pods
NAME READY STATUS RESTARTS AGE
eclipse-jkube-demo-project-gradle-s2i-2-build 0/1 Completed 0 3m10s
eclipse-jkube-demo-project-gradle : $ oc get bc
NAME TYPE FROM LATEST
eclipse-jkube-demo-project-gradle-s2i Source Binary 2
eclipse-jkube-demo-project-gradle : $ oc get build
NAME TYPE FROM STATUS STARTED DURATION
eclipse-jkube-demo-project-gradle-s2i-2 Source Binary Complete 3 minutes ago 1m14s
Generating OpenShift manifests is not very different from generating Kubernetes manifests. Only DeploymentConfig is used in place of Deployment. Here is demonstration of oc:resource goal:
gradle ocResource
gradle ocApply
Once deployed you can see your application inside OpenShift console:
You can then try to access your application via the created Route:
$ oc get pods
NAME READY STATUS RESTARTS AGE
eclipse-jkube-demo-project-gradle-1-bl4dn 1/1 Running 0 3m17s
eclipse-jkube-demo-project-gradle-1-deploy 0/1 Completed 0 3m19s
eclipse-jkube-demo-project-gradle-s2i-1-build 0/1 Completed 0 5m24s
$ oc get routes
NAME HOST/PORT PATH SERVICES PORT TERMINATION WILDCARD
eclipse-jkube-demo-project-gradle eclipse-jkube-demo-project-gradle-rokumar-dev.apps.sandbox.x8i5.p1.openshiftapps.com eclipse-jkube-demo-project-gradle 8080 None eclipse-jkube-demo-project-gradle-rokumar-dev.apps.sandbox.x8i5.p1.openshiftapps.comr-dev.apps.sandbox.x8i5.p1.openshiftapps.com
$ curl eclipse-jkube-demo-project-gradle-rokumar-dev.apps.sandbox.x8i5.p1.openshiftapps.com
Hello JKube!