Prepare application for Azure Container Service (AKS)

In this tutorial, part one of eight, a multi-container application is prepared for use in Kubernetes. Steps completed include:

  • Cloning application source from GitHub
  • Creating a container image from the application source
  • Testing the application in a local Docker environment

Once completed, the following application is accessible in your local development environment.

Image of Kubernetes cluster on Azure

In subsequent tutorials, the container image is uploaded to an Azure Container Registry, and then run in an AKS cluster.

Before you begin

This tutorial assumes a basic understanding of core Docker concepts such as containers, container images, and basic docker commands. If needed, see Get started with Docker for a primer on container basics.

To complete this tutorial, you need a Docker development environment. Docker provides packages that easily configure Docker on any Mac, Windows, or Linux system.

Azure Cloud Shell does not include the Docker components required to complete every step this tutorial. Therefore, we recommend using a full Docker development environment.

Get application code

The sample application used in this tutorial is a basic voting app. The application consists of a front-end web component and a back-end Redis instance. The web component is packaged into a custom container image. The Redis instance uses an unmodified image from Docker Hub.

Use git to download a copy of the application to your development environment.

git clone https://github.com/Azure-Samples/azure-voting-app-redis.git

Change directories so that you are working from the cloned directory.

cd azure-voting-app-redis

Inside the directory is the application source code, a pre-created Docker compose file, and a Kubernetes manifest file. These files are used throughout the tutorial set.

Create container images

Docker Compose can be used to automate the build out of container images and the deployment of multi-container applications.

Run the docker-compose.yml file to create the container image, download the Redis image, and start the application.

docker-compose up -d

When completed, use the docker images command to see the created images.

docker images

Notice that three images have been downloaded or created. The azure-vote-front image contains the application and uses the nginx-flask image as a base. The redis image is used to start a Redis instance.

REPOSITORY                   TAG        IMAGE ID            CREATED             SIZE
azure-vote-front             latest     9cc914e25834        40 seconds ago      694MB
redis                        latest     a1b99da73d05        7 days ago          106MB
tiangolo/uwsgi-nginx-flask   flask      788ca94b2313        9 months ago        694MB

Run the docker ps command to see the running containers.

docker ps

Output:

CONTAINER ID        IMAGE             COMMAND                  CREATED             STATUS              PORTS                           NAMES
82411933e8f9        azure-vote-front  "/usr/bin/supervisord"   57 seconds ago      Up 30 seconds       443/tcp, 0.0.0.0:8080->80/tcp   azure-vote-front
b68fed4b66b6        redis             "docker-entrypoint..."   57 seconds ago      Up 30 seconds       0.0.0.0:6379->6379/tcp          azure-vote-back

Test application locally

Browse to http://localhost:8080 to see the running application.

Image of Kubernetes cluster on Azure

Clean up resources

Now that application functionality has been validated, the running containers can be stopped and removed. Do not delete the container images. The azure-vote-front image is uploaded to an Azure Container Registry instance in the next tutorial.

Run the following to stop the running containers.

docker-compose stop

Delete the stopped containers and resources with the following command.

docker-compose down

At completion, you have a container image that contains the Azure Vote application.

Next steps

In this tutorial, an application was tested and container images created for the application. The following steps were completed:

  • Cloning the application source from GitHub
  • Created a container image from application source
  • Tested the application in a local Docker environment

Advance to the next tutorial to learn about storing container images in an Azure Container Registry.