In this tutorial we will:
- Step 1: Build an ASP.NET Core app and push the sources to a Git repository
- Step 2: Setup the required Azure resources (Web App for Containers, etc.)
- Step 3: Setup an Azure DevOps CI build which builds a Docker image and pushes it to a private Azure Container registry (ACR)
- Step 4: Create an Azure DevOps release pipeline which deploys the new Docker image to a Linux based Web App for Containers (App Service)
Important: The tutorial is using the name
DockerDemo for the demo project and Azure resources. It is recommended to use a new name for your sample app, because the name
DockerDemo is now in use and cannot be used for new Azure resources.
Step 1: Create an ASP.NET Core project
In this step we will implement an ASP.NET Core sample app, add the Azure DevOps YAML build scripts and push everything to a Git repository. The sample app and build script can ge found on GitHub/RSuter/DockerDemo. You can skip this part of the tutorial and directly use this public repository.
To manually create the app and build script, follow these steps:
- Create a new directory for your new repository
- Create a new ASP.NET Core project (with Linux Docker support) in the
In the root of the repository, add the YAML build script
pool: vmImage: 'Ubuntu 16.04' variables: imageName: 'docker-demo:$(Build.BuildId)' steps: - script: docker build -f DockerDemo/Dockerfile -t $(dockerId).azurecr.io/$(imageName) . workingDirectory: src/ displayName: 'Docker Build' - script: | docker login -u $(dockerId) -p $pswd $(dockerId).azurecr.io docker push $(dockerId).azurecr.io/$(imageName) env: pswd: $(dockerPassword) workingDirectory: src/ displayName: 'Docker Push'
This Azure DevOps YAML build script will build the Dockerfile in
src/DockerDemoand push it to the Container registry tagged with current build id. Because the CI build triggers a release with the same build id, the build pipeline is able to deploy this exact version. It is common practice to build a docker image only once and deploy it to all the different environments.
Your file structure and solution should now look as follows:
Commit all your files and push the repository to your Azure DevOps project’s repository.
Step 2: Create the Azure Resources
In the second step, we will setup all required Azure resources: A Container registry, a Web App for Containers and its service plan:
- Browse to the Azure Portal
- Create a new resource group with the name
- Create a new Azure Container Registry called
- In the “Access keys” section, enable admin user so that a registry password is generated
- Create a new Web App for Containers (Linux) resource with the name
DockerDemoAppServiceand a new App Service Plan called
After these steps, you should end up with a resource group with the following resources:
Step 3: Create the build definition
Now, we will setup the build definition in Azure DevOps:
- Browse to your Azure DevOps project, navigate to Pipelines/Build and create a new build pipeline
Select your repository: The UI should automatically select your
After creating the build definition, add the following build variables so that the script can successfully run:
dockerId: The name of the “Container registry” (without azurecr.io, e.g.
dockerPassword: The registry password which can be found in the Azure Portal by opening the “Container registry” resource and retrieving the password under “Access keys”
Now, you can run a build against your repository and the Container registry should be populated with a new image called
docker-demowith the tag set to the current build id:
Step 4: Create the release pipeline
In this step, we will create a new release pipeline which is triggered by a successful build.
Limitation: At the moment, the Azure App Service task only supports deploying a single Docker image to the App Service. I think more tasks to deploy “image groups” via Docker Compose or Kubernetes will be supported soon.
- Create a new release pipeline
Select the artifact from your build definition and enable the continuous deployment trigger:
Create a new “Azure App Service deployment”
Click on the first stage and create a new “Azure App Service deployment”
Prepare the newly created stage/environment:
- Select a subscription and the app service name
- Set the “App type” to “Linux app”
- In “Image Source” select “Container Registry”
- Enter the registry address and select the image
Edit the “Deploy Azure App Service” task:
$(Build.BuildId)as “Tag” so that the correct Docker image version from the associated CI build is deployed
Now, if you commit a change to your Git repository, a new CI build is triggered, a new image version is pushed and eventually a new release is created. This release will update the used image tag in the App Service which will trigger the actual image deployment.
Tags: App Service, ASP.NET Core, Azure, Container, DevOps, Docker, Microservices, Web App