Running the Java Bookshelf app on Google Kubernetes Engine

This tutorial shows how to run the Java Bookshelf App on Google Kubernetes Engine (GKE). Follow this tutorial to containerize and deploy an existing Java web app to GKE. It is highly recommended that you work through the Bookshelf app documentation as part of the tutorial for the App Engine standard environment.

Objectives

  • Create a GKE cluster.
  • Containerize a Java app.
  • Create a replicated frontend for the Bookshelf app.
  • Create a load-balanced service to route HTTP traffic to the Bookshelf frontend.

Costs

This tutorial uses billable components of Google Cloud Platform (GCP), including:

  • GKE
  • Compute Engine
  • Cloud Storage
  • Cloud Datastore
  • Cloud Pub/Sub

Use the Pricing Calculator to generate a cost estimate based on your projected usage. New GCP users might be eligible for a free trial.

Before you begin

  1. Sign in to your Google Account.

    If you don't already have one, sign up for a new account.

  2. Select or create a GCP project.

    Go to the Manage resources page

  3. Make sure that billing is enabled for your project.

    Learn how to enable billing

  4. Enable the Cloud Datastore, Kubernetes Engine, Cloud Storage, Cloud Pub/Sub, and Google+ APIs.

    Enable the APIs

  5. Install and initialize the Cloud SDK.
  6. Install Docker. Docker is used to build container images locally.
  7. Install kubectl.
    gcloud components install kubectl

Creating a GKE cluster

A GKE cluster is a managed set of Compute Engine virtual machines that operate as a single GKE cluster. This tutorial needs a cluster with a minimum of two nodes, and these nodes need access to all Google APIs.

  1. Create the cluster. Replace [YOUR_GCP_ZONE] with the GCP zone where you want to host your cluster.

    gcloud container clusters create bookshelf \
        --scopes "cloud-platform" \
        --num-nodes 2 \
        --enable-basic-auth \
        --issue-client-certificate \
        --enable-ip-alias \
        --zone [YOUR_GCP_ZONE]
    
  2. Verify that you have access to the cluster. The following command lists the nodes in your container cluster and indicates that your container cluster is up and running and that you have access to it.

    kubectl get nodes
    

You use the kubectl command to create resources in a GKE cluster. To learn more about kubectl, see GKE Cluster Operations. In general, you use gcloud to manage resources in your GCP project and you use kubectl to manage resources within your GKE cluster. A single project can have multiple clusters, which makes it easy to have clusters that are made up of different machine types to satisfy different needs.

When you create a cluster with gcloud, it automatically sets up authentication for kubectl. Clusters created by using the Google Cloud Platform Console can set up authentication using the gcloud container clusters get-credentials command.

Cloning the sample app

The sample app is available on GitHub at GoogleCloudPlatform/getting-started-java.

  1. Clone the repository.

    git clone https://github.com/GoogleCloudPlatform/getting-started-java.git
    
  2. Navigate to the sample directory.

    cd getting-started-java/bookshelf/optional-kubernetes-engine
    

Initializing Cloud Datastore

The Bookshelf app uses Cloud Datastore to store the books. To initialize Cloud Datastore in your project for the first time, complete the following steps:

  1. Open Cloud Datastore in the GCP Console.

  2. Select a region for your datastore and click Continue. When you reach the Create an Entity page, close the window as the Bookshelf app is ready to create entities on Cloud Datastore.

Creating a Cloud Storage bucket

The Bookshelf app uses Cloud Storage to store image files.

The following instructions show how to create a Cloud Storage bucket. Buckets are the basic containers that hold your data in Cloud Storage.

Name your bucket the same as your project ID. In the following commands, replace [YOUR-PROJECT-ID] with your project ID.

  1. Create the bucket.

    gsutil mb gs://[YOUR-PROJECT-ID]
  2. Set the bucket's default Access Control List (ACL) to public-read to enable users to see their uploaded images.

    gsutil defacl set public-read gs://[YOUR-PROJECT-ID]

Containerizing the app

The sample app includes a Dockerfile, which is used create the app's Docker image. This Docker image runs the app on GKE.

# The Google App Engine python runtime is Debian Jessie with Python installed
# and various os-level packages to allow installation of popular Python
# libraries. The source is on github at:
#   https://github.com/GoogleCloudPlatform/python-docker
FROM gcr.io/google_appengine/jetty9


# Add application code.
ADD target/bookshelf-gke-1.0-SNAPSHOT/ /app

  1. Package the Bookshelf app.

    mvn clean -DprojectID=[YOUR_PROJECT_ID] package
    
  2. Build the app's Docker image.

    docker build -t gcr.io/[YOUR_PROJECT_ID]/bookshelf
    
  3. Push the image to Google Container Registry so that your cluster can access the image.

    gcloud docker -- push gcr.io/[YOUR_PROJECT_ID]/bookshelf
    

Deploying the Bookshelf frontend

The Bookshelf app is comprised of a set of frontend servers that handles and processes the web requests.

The cluster resources needed to run the frontend are defined in bookshelf-frontend.yaml. These resources are described as a Kubernetes Deployment. Deployments make it easy to create and update a replica set and its associated pods.

# Copyright 2017 Google Inc.
#
# 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

# This file configures the bookshelf application frontend. The frontend serves
# public web traffic.

apiVersion: extensions/v1beta1
kind: Deployment
metadata:
  name: bookshelf-frontend
  labels:
    app: bookshelf

# The bookshelf frontend replica set ensures that at least 3
# instances of the bookshelf app are running on the cluster.
# For more info about Pods see:
#   https://cloud.google.com/kubernetes-engine/docs/pods/
spec:
  replicas: 3

  template:
    metadata:
      labels:
        app: bookshelf
        tier: frontend

    spec:
      containers:
      - name: bookshelf-app
        # Replace [GCLOUD_PROJECT] with your project ID.
        image: gcr.io/[GCLOUD_PROJECT]/bookshelf

        # This setting makes nodes pull the docker image every time before
        # starting the pod. This is useful when debugging, but should be turned
        # off in production.
        imagePullPolicy: Always

        # The bookshelf process listens on port 8080 for web traffic by default.
        ports:
        - name: http-server
          containerPort: 8080
  1. In bookshelf-frontend.yaml, replace [GCLOUD_PROJECT] with your project ID.
  2. Deploy the resources to the cluster.

    kubectl create -f bookshelf-frontend.yaml
    
  3. Track the status of the deployment.

    kubectl get deployments
    

    Once the deployment has the same number of available pods as desired pods, the deployment is complete. If you run into issues with the deployment, you can delete it and start over.

    kubectl delete deployments bookshelf-frontend
    
  4. Once the deployment is complete you can see the pods that the deployment created.

    kubectl get pods
    

Creating the Bookshelf service

Kubernetes Services provide a single point of access to a set of pods. While it's possible to access a single pod, pods are ephemeral and it's usually more convenient to address a set of pods with a single endpoint. In the Bookshelf app, the Bookshelf service allows you to access the Bookshelf frontend pods from a single IP address. This service is defined in bookshelf-service.yaml.

# Copyright 2017 Google Inc.
#
# 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

# The bookshelf service provides a load-balancing proxy over the bookshelf
# frontend pods. By specifying the type as a 'LoadBalancer', Kubernetes Engine
# will create an external HTTP load balancer.
# For more information about Services see:
#   https://cloud.google.com/kubernetes-engine/docs/services/
# For more information about external HTTP load balancing see:
#   https://cloud.google.com/kubernetes-engine/docs/load-balancer
apiVersion: v1
kind: Service

metadata:
  name: bookshelf-frontend
  labels:
    app: bookshelf
    tier: frontend

spec:
  type: LoadBalancer
  ports:
  - port: 80
    targetPort: http-server
  selector:
    app: bookshelf
    tier: frontend

Notice that the pods and the service that uses the pods are separate. Kubernetes uses labels to select the pods that a service addresses. With labels, you can have a service that addresses pods from different replica sets and have multiple services that point to an individual pod.

  1. Create the Bookshelf service.

    kubectl create -f bookshelf-service.yaml
    
  2. Get the service's external IP address.

    kubectl describe service bookshelf
    

    Note that it may take up to 60 seconds for the IP address to be allocated. The external IP address is listed under LoadBalancer Ingress.

Accessing the Bookshelf app

You have now deployed all the resources needed to run the Bookshelf app on GKE. Use the external IP address from the previous step to load the app in your web browser and create books.

Cleaning up

To avoid incurring charges to your Google Cloud Platform account for the resources used in this tutorial:

Delete the project

The easiest way to eliminate billing is to delete the project you created for the tutorial.

To delete the project:

  1. In the GCP Console, go to the Projects page.

    Go to the Projects page

  2. In the project list, select the project you want to delete and click Delete.
  3. In the dialog, type the project ID, and then click Shut down to delete the project.

Delete the cluster

Deleting the cluster removes all GKE and Compute Engine resources, but you need to manually remove any resources in Cloud Storage, Cloud Datastore, and Cloud Pub/Sub.

Delete the cluster using the following command. Replace [YOUR_GCP_ZONE] with the zone you used when creating the cluster.

gcloud container clusters delete bookshelf --zone [YOUR_GCP_ZONE]

What's next

  • Try out other Google Cloud Platform features for yourself. Have a look at our tutorials.
  • Explore other GCP services.
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