Azure Container Registry (ACR) is a managed Docker registry service based on the open-source Docker Registry 2.0. It allows developers to store and manage images for all types of container deployments. In the context of the AZ-204 Developing Solutions for Microsoft Azure exam, the purpose of this post is to provide an illustrative guide on how to publish an image to Azure Container Registry.
1. Creating an Azure Container Registry
Before you can publish an image to ACR, you’ll need to create an ACR instance:
- Navigate to the Azure portal.
- Click on “Create a resource” and search “Container Registry” in the marketplace.
- Select “Container Registry” from the dropdown menu and click “Create”.
- In the new window, provide the necessary information such as Registry name, Resource group, Location, and SKU. Click “Review + Create” and then “Create”.
2. Login to Azure Container Registry
Once the ACR instance is created, log in to the registry using Azure CLI. Replace `
az acr login –name
If the login process is successful, you will see a message that says “Login Succeeded”.
3. Publishing an Image to ACR
After creating and logging into the ACR, you can now build a Docker image and publish this to the ACR.
Firstly, navigate to the directory containing the Dockerfile and use the `docker build` command to build your Docker image:
docker build . -t
Rename the image to include the login server name of your ACR instance:
docker tag
Lastly, push the image to the ACR using the `docker push` command:
docker push
4. Verifying the Image Upload to ACR
To confirm if your Docker image has been successfully pushed to ACR, list all the images in your ACR using the Azure CLI `az acr repository show-tags` command:
az acr repository show-tags –name
This will display a table showing all the image tags in the specified repository.
In Conclusion
In conclusion, Azure Container Registry provides a secure, scalable, and reliable Docker image storage solution that supports the build, store, secure, scan, replicate, connect, and deploy workflows. Familiarity with ACR and Docker is an essential part of preparing for the AZ-204 Developing Solutions for Microsoft Azure exam. With this guide, you have learned how to create an Azure Container Registry, push images to your registry, and verify the publication of images to your ACR.
Practice Test
True or False: You need to specify the login server in the repository when managing manifests in Azure Container Registry.
- True
- False
Answer: True.
Explanation: When managing manifests in Azure Container Registry, you need to specify the login server in the repository.
Which of these are required to publish an image to Azure Container Registry?
- a. Registry Name
- b. Microsoft Account
- c. Docker Desktop
- d. Azure Container Instances
Answer: a, c.
Explanation: To publish an image to Azure Container Registry, a registry name and Docker Desktop are required for organizing Docker images and pushing them to the registry.
True or False: The ‘az acr build’ command can be used to deploy a Dockerfile to Azure Container Registry.
- True
- False
Answer: True.
Explanation: The ‘az acr build’ command is used to automatically build a Docker image and deploy it to an Azure Container Registry.
To publish an image to Azure Container Registry, you must run which command after ‘docker tag’?
- a. docker pull
- b. docker push
- c. docker run
- d. docker build
Answer: b. docker push
Explanation: After running ‘docker tag’, the ‘docker push’ command is used to push the image to the Azure Container Registry.
True or False: Azure Container Registry supports both Windows and Linux containers.
- True
- False
Answer: True.
Explanation: Azure Container Registry supports both Windows and Linux containers, keeping them in securely private registries.
To log into Azure Container Registry from Docker, which command should be used?
- a. az acr login –name
- b. az acr push –name
- c. docker login
- d. docker push
Answer: c. docker login
Explanation: The ‘docker login’ command is used to log into Azure Container Registry from Docker.
True or False: An Azure subscription is not necessary for pushing Docker images to Azure Container Registry.
- True
- False
Answer: False.
Explanation: An Azure subscription is necessary to create and manage Azure Container Registry that is used for pushing Docker images.
To publish an image to Azure Container Registry, you must have ________________ installed.
- a. Docker Desktop
- b. Azure Command Line Interface (CLI)
- c. Both a and b
- d. Visual Studio Code
Answer: c. Both a and b
Explanation: Both Docker Desktop and Azure Command Line Interface (CLI) are required to publish an image to Azure Container Registry.
True or False: You can use ReactJS to publish an image to Azure Container Registry.
- True
- False
Answer: False.
Explanation: Publishing an image to Azure Container Registry requires using Docker and Azure CLI, not ReactJS.
Which feature allows you to automatically build and push images to Azure Container Registry when you commit changes to your repository?
- a. PostgresDB
- b. Azure DevOps Pipeline
- c. Triggers
- d. Kubernetes
Answer: b. Azure DevOps Pipeline
Explanation: Azure DevOps Pipeline can be set up to automatically build and push images to Azure Container Registry when changes are committed to your repository.
True or False: Static websites can be hosted on Azure Container Registry.
- True
- False
Answer: False.
Explanation: Azure Container Registry is used for managing Docker and Open Container Initiative (OCI) images, it’s not used for hosting static websites.
Does Azure Container Registry support OCI Artifacts?
- a. Yes
- b. No
Answer: a. Yes
Explanation: Azure Container Registry fully supports OCI Artifacts, a way of expanding the types of content that can be stored in a registry. This also increases interoperability between registries.
True or False: Azure Container Registry allows you to use either private or public repositories.
- True
- False
Answer: False.
Explanation: Azure Container Registry only allows you to use private repositories for security reasons, it does not support public ones.
What does the ‘–registry’ option in the ‘az acr login –name’ command specify?
- a. The name of the Azure Container Registry.
- b. The password for the Azure Container Registry.
- c. The name of the image to be pushed.
- d. The name of the Docker machine.
Answer: a. The name of the Azure Container Registry.
Explanation: The ‘–registry’ or ‘–name’ option in the ‘az acr login’ command specifies the name of the Azure Container Registry.
True or False: Azure Container Registry integrates well with Azure Kubernetes Service.
- True
- False
Answer: True.
Explanation: Azure Kubernetes Service (AKS) works well with Azure Container Registry, enabling you to run your applications with managed Kubernetes efficiently while using images stored in your private Docker registry.
Interview Questions
What is Azure Container Registry?
Azure Container Registry is a managed, private Docker registry service based on the open-source Docker Registry 2.0. It is used to create and maintain Azure container registries to store and manage private Docker container images and related content.
What command is used to login to the Azure Container Registry?
The command “
az acr login --name " is used to login to the Azure Container Registry.
How do you publish an image to the Azure Container Registry?
To publish an image to the Azure Container Registry, use the Docker CLI to tag the image with the login server of the registry, and then push the image to the registry.
What is the purpose of the "docker tag" command when publishing an image to Azure Container Registry?
The "
docker tag" command creates a tagged version of your image. You can use the tag to version your container images, and you need to tag the image with the fully qualified registry name to be able to push it to Azure Container Registry.
How do you tag an image for Azure Container Registry?
To tag an image for Azure Container Registry, use the "
docker tag" command with the syntax "
docker tag source-image:tag registry-name.azurecr.io/repository-name:image-tag".
How do you push an image to Azure Container Registry?
To push an image to Azure Container Registry, use the "
docker push" command after logging into your registry and tagging your image. The syntax is "
docker push registry-name.azurecr.io/repository-name:image-tag".
What role is needed to push and pull images in an Azure Container Registry?
The AcrPush role is necessary to push and pull images in an Azure Container Registry.
Can you pull images from Azure Container Registry without logging in?
No, you cannot pull images from Azure Container Registry without logging in. You must authenticate through the Azure CLI, the Docker CLI, or an Azure service principal.
What is the purpose of the "docker login" command when working with Azure Container Registry?
The "
docker login" function is used to authenticate with a registry. When working with Azure Container Registry, it authenticates your Docker client to the registry.
What do you need in order to authenticate with an Azure Container Registry through Azure Active Directory?
In order to authenticate with an Azure Container Registry through Azure Active Directory, you need to create a service principal and assign it a role for the registry.
What is the Azure CLI command to create a repository in Azure Container Registry?
There isn't a specific Azure CLI command to create a repository in Azure Container Registry. A new repository is created automatically when you push an image to it.
Why would you use Azure Container Registry Tasks?
Azure Container Registry Tasks is used to automate build, test and patch container images in the cloud, which simplifies the management of image-related workflows.
Can Azure Container Registry work with both Linux and Windows-based containers?
Yes, Azure Container Registry works with both Linux and Windows-based containers.
What is Geo-replication in Azure Container Registry?
Geo-replication enables an Azure container registry to function as a single registry while being available in multiple Azure locations. This capability provides network-close registry access from regional deployments to mitigate network latency.
Is Azure Container Registry compliant with the Docker Registry HTTP API V2?
Yes, Azure Container Registry is compliant with the Docker Registry HTTP API V2, making it compatible with your Docker CLI tools and Docker Compose, Kubernetes, etc.
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