Quickstart: Deploying a language-specific app

This page shows you how to do the following:

1. Create a Hello World app.
2. Package the app into a container image using Cloud Build.
3. Create a cluster in Google Kubernetes Engine (GKE).
4. Deploy the container image to your cluster.

The sample is shown in several languages, but note that you can use other languages in addition to the ones shown.

Before you begin

1. Sign in to your Google Account.

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

2. In the Cloud Console, on the project selector page, select or create a Cloud project.

   Note: If you don't plan to keep the resources that you create in this procedure, create a project instead of selecting an existing project. After you finish these steps, you can delete the project, removing all resources associated with the project.

   Go to the project selector page

3. Make sure that billing is enabled for your Google Cloud project. Learn how to confirm billing is enabled for your project.

4. Enable the Cloud Build and Google Kubernetes Engine APIs.

   Enable the APIs

5. Install and initialize the Cloud SDK.
6. kubectl is used to manage Kubernetes, the cluster orchestration system used by GKE. You can install kubectl by using gcloud:

   gcloud components install kubectl

Writing the sample app

For instructions on creating a Hello World app that runs on GKE, click your language:

Go

1. Create a new directory named helloworld-gke and change directory into it:

   mkdir helloworld-gke
   cd helloworld-gke
   

2. Create a new module named example.com/helloworld:

   go mod init example.com/helloworld
   

3. Create a new file named helloworld.go and paste the following code into it:

   quickstart/go/helloworld.go

   View on GitHub

   package main
   
   import (
   	"fmt"
   	"log"
   	"net/http"
   	"os"
   )
   
   func main() {
   	http.HandleFunc("/", handler)
   	port := os.Getenv("PORT")
   	if port == "" {
   		port = "8080"
   	}
   	log.Printf("Listening on localhost:%s", port)
   	log.Fatal(http.ListenAndServe(fmt.Sprintf(":%s", port), nil))
   }
   
   func handler(w http.ResponseWriter, r *http.Request) {
   	log.Print("Hello world received a request.")
   	target := os.Getenv("TARGET")
   	if target == "" {
   		target = "World"
   	}
   	fmt.Fprintf(w, "Hello %s!\n", target)
   }
   

   This code creates a web server that listens on the port defined by the PORT environment variable.

Your app is finished and ready to be packaged in a Docker container, and then uploaded to Container Registry.

Node.js

1. Create a new directory named helloworld-gke and change directory into it:

   mkdir helloworld-gke
   cd helloworld-gke
   

2. Create a package.json file with the following contents:

   quickstart/nodejs/package.json

   View on GitHub

   {
     "name": "gke-helloworld",
     "version": "1.0.0",
     "description": "GKE hello world sample in Node",
     "main": "index.js",
     "scripts": {
       "start": "node index.js"
     },
     "author": "",
     "license": "Apache-2.0",
     "dependencies": {
       "express": "^4.16.4"
     }
   }
   

3. In the same directory, create a index.js file, and copy the following lines into it:

   quickstart/nodejs/index.js

   View on GitHub

   const express = require('express');
   const app = express();
   
   app.get('/', (req, res) => {
     console.log('Hello world received a request.');
   
     const target = process.env.TARGET || 'World';
     res.send(`Hello ${target}!`);
   });
   
   const port = process.env.PORT || 8080;
   app.listen(port, () => {
     console.log('Hello world listening on port', port);
   });
   

   This code creates a web server that listens on the port defined by the PORT environment variable.

Your app is finished and ready to be packaged in a Docker container and uploaded to Container Registry.

Python

1. Create a new directory named helloworld-gke and change directory into it:

   mkdir helloworld-gke
   cd helloworld-gke
   

2. Create a file named app.py and paste the following code into it:

   quickstart/python/app.py

   View on GitHub

   import os
   
   from flask import Flask
   
   app = Flask(__name__)
   
   @app.route('/')
   def hello_world():
       target = os.environ.get('TARGET', 'World')
       return 'Hello {}!\n'.format(target)
   
   if __name__ == "__main__":
       app.run(debug=True,host='0.0.0.0',port=int(os.environ.get('PORT', 8080)))
   

Java

Create a Spring Boot app.

1. Install Java SE 8 or higher JDK and cURL. Java SE and cURL are only required to create the new web project in the next step. The Dockerfile, which is described later, loads all dependencies into the container.

2. From your terminal, create a new empty web project:

   curl https://start.spring.io/starter.zip \
       -d dependencies=web \
       -d javaVersion=1.8 \
       -d bootVersion=2.1.3.RELEASE \
       -d name=helloworld \
       -d artifactId=helloworld \
       -d baseDir=helloworld-gke \
       -o helloworld-gke.zip
   unzip helloworld-gke.zip
   cd helloworld-gke
   

   You now have a new Spring Boot project in helloworld-gke.

3. In the src/main/java/com/example/helloworld/HelloworldApplication.java file, Update the HelloworldApplication class by adding a @RestController to handle the / mapping.

   quickstart/java/src/main/java/com/example/helloworld/HelloworldApplication.java

   View on GitHub

   package com.example.helloworld;
   
   import org.springframework.beans.factory.annotation.Value;
   import org.springframework.boot.SpringApplication;
   import org.springframework.boot.autoconfigure.SpringBootApplication;
   import org.springframework.web.bind.annotation.GetMapping;
   import org.springframework.web.bind.annotation.RestController;
   
   @SpringBootApplication
   public class HelloworldApplication {
   
   	@Value("${TARGET:World}")
   	String target;
   
   	@RestController
   	class HelloworldController {
   		@GetMapping("/")
   		String hello() {
   			return "Hello " + target + "!";
   		}
   	}
   
   	public static void main(String[] args) {
   		SpringApplication.run(HelloworldApplication.class, args);
   	}
   }
   

   This code creates a web server that listens on the port defined by the PORT environment variable.

Your app is finished and ready to be packaged in a Docker container, and then uploaded to Container Registry.

C#

1. Install .NET Core SDK 2.2. .NET Core SDK is only required to create the new web project in the next step. The Dockerfile, which is described later, loads all dependencies into the container.

2. From your terminal, create a new empty web project:

   dotnet new web -o helloworld-gke
   

3. Change directory to helloworld-gke.

4. Update the CreateWebHostBuilder definition in Program.cs by specifying the port URL for .UseUrls() to define the serving port. The sample shows port 8080, but you can use other ports. Your server must listen to whatever port you specify here:

   quickstart/dotnet/Program.cs

   View on GitHub

   // Copyright (c) 2019 Google LLC.
   // 
   // 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.
   
   using System;
   using Microsoft.AspNetCore;
   using Microsoft.AspNetCore.Hosting;
   
   namespace HelloGKE
   {
       public class Program
       {
           public static void Main(string[] args)
           {
               CreateWebHostBuilder(args).Build().Run();
           }
   
           public static IWebHostBuilder CreateWebHostBuilder(string[] args) =>
               WebHost.CreateDefaultBuilder(args)
                   .UseStartup<Startup>()
                   .UsePortEnvironmentVariable();
       }
   
       static class ProgramExtensions
       {
           // Google Cloud Run sets the PORT environment variable to tell this
           // process which port to listen to.
           public static IWebHostBuilder UsePortEnvironmentVariable(
               this IWebHostBuilder builder)
           {
               string port = Environment.GetEnvironmentVariable("PORT");
               if (!string.IsNullOrEmpty(port))
               {
                   builder.UseUrls($"http://0.0.0.0:{port}");
               }
               return builder;
           }
       }
   }
   

Your app is finished and ready to be packaged in a Docker container, and then uploaded to Container Registry.

PHP

1. Create a new directory named helloworld-gke and change directory into it:

   mkdir helloworld-gke
   cd helloworld-gke
   

2. Create a file named index.php and paste the following code into it:

   quickstart/php/index.php

   View on GitHub

   <?php
   $target = getenv('TARGET', true) ?: 'World';
   echo sprintf("Hello %s!", $target);
   

Your app is finished and ready to be packaged in a Docker container, and then uploaded to Container Registry.

Ruby

1. Create a new directory named helloworld-gke and change directory into it:

   mkdir helloworld-gke
   cd helloworld-gke
   

2. Create a file named app.rb and paste the following code into it:

   quickstart/ruby/app.rb

   View on GitHub

   require 'sinatra'
   
   set :bind, '0.0.0.0'
   set :port, ENV['PORT'] || '8080'
   
   get '/' do
     target = ENV['TARGET'] || 'World'
     "Hello #{target}!\n"
   end
   

   This code creates a web server that listens on the port defined by the PORT environment variable.

3. Create a file named Gemfile and copy the following into it:

   quickstart/ruby/Gemfile

   View on GitHub

   source 'https://rubygems.org'
   
   gem 'sinatra'
   gem 'rack', '>= 2.0.6'
   

Containerizing an app with Cloud Build

1. To containerize the sample app, create a new file named Dockerfile in the same directory as the source files, and copy the following content:

   Go

   quickstart/go/Dockerfile

   View on GitHub

   # Use the offical Golang image to create a build artifact.
   # This is based on Debian and sets the GOPATH to /go.
   # https://hub.docker.com/_/golang
   FROM golang:1.12 as builder
   
   # Copy local code to the container image.
   WORKDIR /app
   COPY . .
   
   # Build the command inside the container.
   RUN CGO_ENABLED=0 GOOS=linux go build -v -o helloworld
   
   # Use a Docker multi-stage build to create a lean production image.
   # https://docs.docker.com/develop/develop-images/multistage-build/#use-multi-stage-builds
   FROM alpine
   RUN apk add --no-cache ca-certificates
   
   # Copy the binary to the production image from the builder stage.
   COPY --from=builder /app/helloworld /helloworld
   
   # Run the web service on container startup.
   CMD ["/helloworld"]
   

   Node.js

   quickstart/nodejs/Dockerfile

   View on GitHub

   # Use the official lightweight Node.js 10 image.
   # https://hub.docker.com/_/node
   FROM node:10-slim
   
   # Create and change to the app directory.
   WORKDIR /usr/src/app
   
   # Copy application dependency manifests to the container image.
   # A wildcard is used to ensure both package.json AND package-lock.json are copied.
   # Copying this separately prevents re-running npm install on every code change.
   COPY package*.json ./
   
   # Install production dependencies.
   RUN npm install --only=production
   
   # Copy local code to the container image.
   COPY . ./
   
   # Run the web service on container startup.
   CMD [ "npm", "start" ]
   

   Add a further .dockerignore file to ensure local files do not affect the container build process:

   quickstart/nodejs/.dockerignore

   View on GitHub

   Dockerfile
   README.md
   node_modules
   npm-debug.log
   

   Python

   quickstart/python/Dockerfile

   View on GitHub

   # Use the official lightweight Python image.
   # https://hub.docker.com/_/python
   FROM python:3.7-slim
   
   # Copy local code to the container image.
   ENV APP_HOME /app
   WORKDIR $APP_HOME
   COPY . ./
   
   # Install production dependencies.
   RUN pip install Flask gunicorn
   
   # Run the web service on container startup. Here we use the gunicorn
   # webserver, with one worker process and 8 threads.
   # For environments with multiple CPU cores, increase the number of workers
   # to be equal to the cores available.
   CMD exec gunicorn --bind :$PORT --workers 1 --threads 8 app:app
   

   Add a .dockerignore file to ensure local files don't affect the container build process:

   quickstart/python/.dockerignore

   View on GitHub

   Dockerfile
   README.md
   *.pyc
   *.pyo
   *.pyd
   __pycache__
   

   Java

   quickstart/java/Dockerfile

   View on GitHub

   # Use the official maven/Java 8 image to create a build artifact.
   # https://hub.docker.com/_/maven
   FROM maven:3.5-jdk-8-alpine as builder
   
   # Copy local code to the container image.
   WORKDIR /app
   COPY pom.xml ./
   COPY src ./src/
   
   # Build a release artifact.
   RUN mvn package -DskipTests
   
   # Use AdoptOpenJDK for base image.
   # It's important to use OpenJDK 8u191 or above that has container support enabled.
   # https://hub.docker.com/r/adoptopenjdk/openjdk8
   # https://docs.docker.com/develop/develop-images/multistage-build/#use-multi-stage-builds
   FROM adoptopenjdk/openjdk8:jdk8u202-b08-alpine-slim
   
   # Copy the jar to the production image from the builder stage.
   COPY --from=builder /app/target/helloworld-*.jar /helloworld.jar
   
   # Run the web service on container startup.
   CMD ["java","-Djava.security.egd=file:/dev/./urandom","-Dserver.port=${PORT}","-jar","/helloworld.jar"]
   

   C#

   quickstart/dotnet/Dockerfile

   View on GitHub

   # Use Microsoft's official lightweight .NET images.
   # https://hub.docker.com/r/microsoft/dotnet
   
   FROM mcr.microsoft.com/dotnet/core/sdk:2.2-alpine AS build
   WORKDIR /app
   
   # Install production dependencies.
   # Copy csproj and restore as distinct layers.
   COPY *.csproj ./
   RUN dotnet restore
   
   # Copy local code to the container image.
   COPY . ./
   
   # Build a release artifact.
   RUN dotnet publish -c Release -o out
   
   # Run the web service on container startup in a lean production image.
   FROM mcr.microsoft.com/dotnet/core/aspnet:2.2-alpine
   WORKDIR /app
   
   COPY --from=build /app/out ./
   CMD ["dotnet", "HelloGKE.dll"]
   

   Add a .dockerignore file to ensure local files don't affect the container build process:

   quickstart/dotnet/.dockerignore

   View on GitHub

   Dockerfile
   README.md
   **/obj/
   **/bin/
   

   PHP

   quickstart/php/Dockerfile

   View on GitHub

   # Use the official PHP 7.2 image.
   # https://hub.docker.com/_/php
   FROM php:7.2-apache
   
   # Copy local code to the container image.
   COPY index.php /var/www/html/
   
   # Use port 8080 in Apache configuration files.
   RUN sed -i 's/80/${PORT}/g' /etc/apache2/sites-available/000-default.conf /etc/apache2/ports.conf
   
   # Configure PHP for development.
   # Switch to the production php.ini for production operations.
   # RUN mv "$PHP_INI_DIR/php.ini-production" "$PHP_INI_DIR/php.ini"
   # https://hub.docker.com/_/php#configuration
   RUN mv "$PHP_INI_DIR/php.ini-development" "$PHP_INI_DIR/php.ini"
   

   Add a .dockerignore file to ensure local files don't affect the container build process:

   quickstart/php/.dockerignore

   View on GitHub

   Dockerfile
   README.md
   vendor
   

   Ruby

   quickstart/ruby/Dockerfile

   View on GitHub

   # Use the official lightweight Ruby image.
   # https://hub.docker.com/_/ruby
   FROM ruby:2.5-slim
   
   # Install production dependencies.
   WORKDIR /usr/src/app
   COPY Gemfile ./
   RUN bundle install
   
   # Copy local code to the container image.
   COPY . ./
   
   # Run the web service on container startup.
   CMD ["ruby", "./app.rb"]
   

2. Get your Google Cloud project ID:

   gcloud config get-value project
   

   Build your container image using Cloud Build, which is similar to running docker build and docker push, but it happens on Google Cloud. Replace project-id with your Google Cloud ID:

   gcloud builds submit --tag gcr.io/project-id/helloworld-gke .
   

   The image is stored in Container Registry.

Creating a Kubernetes Engine cluster

A GKE cluster is a managed set of Compute Engine virtual machines that operate as a single GKE cluster. This tutorial uses a single node.

1. Create the cluster. Replace your-gcp-zone with the Google Cloud zone where you want to host your cluster. For a complete list, see Geography and regions.

   gcloud container clusters create helloworld-gke \
      --num-nodes 1 \
      --enable-basic-auth \
      --issue-client-certificate \
      --zone your-gcp-zone
   

   Note: A region contains one or more zones. Using a region instead of a zone for the --zone option (for example, us-central1 instead of us-central1-b) creates a node in each zone within the region.
   Note: The default scope is set to --scopes=gke-default. For a full list of available scopes, see OAuth 2.0 scopes for Google APIs.

2. Verify that you have access to the cluster. The following command lists the nodes in your container cluster which are up and running and indicates that you have access to it.

   kubectl get nodes
   

   If you run into errors, refer to the Kubernetes Troubleshooting guide

Deploying to GKE

To deploy your app to the GKE cluster you created, you need two Kubernetes objects.

1. A Deployment to define your app.
2. A Service to define how to access your app.

Deploy an app

The app has a frontend server that handles the web requests. You define the cluster resources needed to run the frontend in a new file called deployment.yaml. These resources are described as a Deployment. You use Deployments to create and update a ReplicaSet and its associated pods.

1. Create the deployment.yaml file in the same directory as your other files and copy the following content, replacing $GCLOUD_PROJECT with your Google Cloud project ID:

   quickstart/deployment.yaml

   View on GitHub

   # This file configures the hello-world app which serves public web traffic.
   apiVersion: extensions/v1beta1
   kind: Deployment
   metadata:
     name: helloworld-gke
   spec:
     replicas: 1
     selector:
       matchLabels:
         app: hello
     template:
       metadata:
         labels:
           app: hello
       spec:
         containers:
         - name: hello-app
           # Replace $GCLOUD_PROJECT with your project ID
           image: gcr.io/$GCLOUD_PROJECT/helloworld-gke:latest
           # This app listens on port 8080 for web traffic by default.
           ports:
           - containerPort: 8080
           env:
             - name: PORT
               value: "8080"
   

2. Deploy the resource to the cluster:

   kubectl apply -f deployment.yaml
   

3. Track the status of the Deployment:

   kubectl get deployments
   

   The Deployment is complete, when all of the AVAILABLE deployments are READY.

   NAME               READY   UP-TO-DATE   AVAILABLE   AGE
   hello-deployment   1/1     1            1           20s
   

   If the Deployment has a mistake, run kubectl apply -f deployment.yaml again to update the Deployment with any changes.

4. After the Deployment is complete, you can see the pods that the Deployment created:

   kubectl get pods
   

Deploy a Service

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 can only be accessed reliably by using a Service address. In your Hello World app, the "hello" Service defines a load balancer to access the hello-app pods from a single IP address. This Service is defined in the service.yaml file.

1. Create the file service.yaml in the same directory as your other source files with the following content:

   quickstart/service.yaml

   View on GitHub

   # The hello service provides a load-balancing proxy over the hello-app
   # pods. By specifying the type as a 'LoadBalancer', Kubernetes Engine will
   # create an external HTTP load balancer.
   apiVersion: v1
   kind: Service
   metadata:
     name: hello
   spec:
     type: LoadBalancer
     selector:
       app: hello
     ports:
     - port: 80
       targetPort: 8080
   

   The pods are defined separately from the Service that uses the pods. 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.

2. Create the Hello World Service:

   kubectl apply -f service.yaml
   

3. Get the Service's external IP address:

   kubectl get services
   

   It can take up to 60 seconds to allocate the IP address. The external IP address is listed under the column EXTERNAL-IP for the hello Service.

   NAME         TYPE           CLUSTER-IP      EXTERNAL-IP     PORT(S)        AGE
   hello        LoadBalancer   10.22.222.222   35.111.111.11   80:32341/TCP   1m
   kubernetes   ClusterIP      10.22.222.1     <none>          443/TCP        20m
   

View a deployed app

You have now deployed all the resources needed to run the Hello World app on GKE. Use the external IP address from the previous step to load the app in your web browser, and see your running app!

# Example cURL call to your running application on GKE (external IP address of service)
curl 35.111.111.11
Hello World!

Clean up

To avoid incurring charges to your Google Cloud account for the resources used in this quickstart, follow these steps.

You are charged for the Compute Engine instances running in your cluster, as well as for the container image in Container Registry.

Delete the project

Deleting your Cloud project stops billing for all the resources used within that project.

Caution: Deleting a project has the following effects:
• Everything in the project is deleted. If you used an existing project for this tutorial, when you delete it, you also delete any other work you've done in the project.
• Custom project IDs are lost. When you created this project, you might have created a custom project ID that you want to use in the future. To preserve the URLs that use the project ID, such as an appspot.com URL, delete selected resources inside the project instead of deleting the whole project.
1. In the Cloud Console, go to the Manage resources page.

   Go to the Manage resources page

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

Delete your cluster and container

If you want to keep your project but only delete the resources used in this tutorial, delete your cluster and image.

To delete a cluster using the gcloud command-line tool, run the following command:

gcloud container clusters delete helloworld-gke

Note: For more information, refer to the documentation on Deleting a cluster.

To delete an image from one of your Container Registry repositories, run the following command:

gcloud container images delete gcr.io/project-id/helloworld-gke

Note: For more information, refer to the documentation on Managing images.

What's next

For more information on Kubernetes, see the following:

• Learn more about creating clusters.
• Learn more about Kubernetes.
• Read the kubectl reference documentation.

For more information on deploying to GKE, see the following:

• Learn how to package, host, and deploy a simple web server application.
• Deploy a Guestbook application with Redis and PHP.
• Deploy a stateful WordPress application with persistent storage and MySQL.
• Setting up Cloud Run on GKE.

For more information on deploying to GKE directly from your IDE with Cloud Code, see the following:

• Cloud Code for VS Code
• Cloud Code for IntelliJ