Publish an image to Azure Container Registry

Azure Container Registry is a private registry for hosting container images. It enables you to store and manage container images for your applications and services. This article will guide you through the process of publishing an image to Azure Container Registry, allowing you to easily distribute and deploy your containerized applications.

Prerequisites

To get started, you will need:

• An Azure subscription
• An Azure Container Registry instance provisioned

If you haven’t done so already, refer to the Azure documentation for detailed instructions on how to create an Azure Container Registry instance.

Step 1: Build your container image

To publish an image to Azure Container Registry, you first need to build your container image. This can be done using popular container build tools like Docker or Azure Container Instances. For this demonstration, we will use Docker.

Assuming you have Docker installed, create a Dockerfile in the root of your application directory. The Dockerfile defines the necessary instructions to build your image. Here is a sample Dockerfile for a Node.js application:

FROM node:14-alpine
WORKDIR /app
COPY package.json .
RUN npm install
COPY . .
CMD [ "npm", "start" ]

Save the Dockerfile and navigate to your application directory in a command-line interface.

Step 2: Tag the image

Before you can push the image to Azure Container Registry, you need to tag it with the login server address of your registry. Run the following command, replacing myregistry.azurecr.io with the login server address of your registry:

docker build -t myregistry.azurecr.io/myimage:tag .

This command builds the Docker image and assigns it the desired tag.

Step 3: Log in to Azure Container Registry

To push the image to Azure Container Registry, you need to log in to the registry in Docker. Use the following command, replacing myregistry with the name of your registry:

docker login myregistry.azurecr.io

Enter your Azure Container Registry credentials when prompted.

Step 4: Push the image

Now that you are logged in to Azure Container Registry, you can push the image using the following command:

docker push myregistry.azurecr.io/myimage:tag

This command pushes the image to your Azure Container Registry.

Step 5: Verify the image in Azure Container Registry

To verify that the image has been successfully published to Azure Container Registry, you can use the Azure portal or the Azure CLI.

Using the Azure portal, navigate to your Azure Container Registry instance and select the “Repositories” tab. You should see the repository name and the corresponding tag for the pushed image.

Alternatively, you can use the Azure CLI to list the repositories and tags within your registry. Run the following command, replacing myregistry with the name of your registry:

az acr repository list --name myregistry --output table

This command lists all the repositories in your Azure Container Registry, along with their tags.

And that’s it! You have successfully published an image to Azure Container Registry. You can now use this image to deploy your containerized applications to Azure services like Azure Kubernetes Service or Azure Web App for Containers.

Remember to clean up any local Docker images or containers that are no longer needed to avoid unnecessary resource consumption.

In this article, we covered the basic steps to publish an image to Azure Container Registry using Docker. However, Azure Container Registry provides more advanced features like build tasks, webhook triggers, and geo-replication. Refer to the official Azure documentation for more details on these advanced topics and to explore further possibilities with Azure Container Registry.