In Azure DevOps, Docker tasks are a part of the pipeline configuration and are used to build, push, and deploy Docker images. These tasks make it easier to integrate Docker into your CI/CD process. Here’s a general overview of how you can use Docker tasks in Azure DevOps:

1. Prerequisites

• Azure DevOps Account: Ensure you have an Azure DevOps account and a project created.
• Docker Hub or Azure Container Registry (ACR): Have an account on Docker Hub or an Azure Container Registry to push and store your Docker images.
• Dockerfile: Ensure your project has a Dockerfile which defines how your Docker image should be built.

2. Creating a Docker Task in a Pipeline

• Define Your Pipeline: Start by defining a pipeline in Azure DevOps. This can be done in the Azure DevOps portal using the YAML editor or by committing a YAML file to your repository.

• Add Docker Task: In your pipeline configuration, add a Docker task. There are different Docker tasks for different purposes:

  • Docker Build: To build an image.
  • Docker Push: To push the image to a Docker registry.
  • Docker Run: To run a Docker container.

• Configure Docker Task: For each Docker task, you need to specify parameters like the path to the Dockerfile, the image name, tags, and the registry to push the image to.

3. Common Parameters for Docker Tasks

• dockerFile: Path to the Dockerfile.
• containerRegistry: Connection to the Docker registry.
• repository: Name of the repository.
• tags: Tags for the image.
• command: The Docker command to run (e.g., build, push, run).

4. Example YAML Configuration for a Docker Build and Push

This example YAML script is for a pipeline that automatically triggers on a push to the master branch. It uses the Docker@2 task to build and push a Docker image to a specified repository.

5. Service Connections

• Before running Docker tasks that interact with a Docker registry, you need to set up a service connection in Azure DevOps to authenticate with your Docker registry.
• This can be Docker Hub, Azure Container Registry, or any other Docker registry you use.

6. Running the Pipeline

• Once your pipeline is configured, commit the changes to your repository.
• Azure DevOps will trigger the pipeline based on the defined triggers (e.g., a push to the master branch).
• The pipeline will execute the Docker tasks as defined, building and pushing the Docker image to your registry.

7. Advanced Scenarios

• Multi-stage Builds: For complex applications, you can define multi-stage Docker builds in your Dockerfile.
• Docker Compose: If your application requires multiple containers, you can use Docker Compose tasks in Azure DevOps.

8. Monitoring and Troubleshooting

• After the pipeline runs, check the logs in Azure DevOps for success or failure messages.
• Troubleshoot any errors by examining the output logs of the pipeline.

By integrating Docker tasks into your Azure DevOps pipelines, you can automate the process of building, pushing, and deploying Docker-based applications, making your CI/CD process more efficient and reliable.