Microsoft offers a managed Docker container service, Azure Container Service (AKS), using which customers can easily deploy scalable, open source APIs-based container deployed applications. The most important aspect that AKS provides is the orchestration and placement-related aspects for the containers, so that the end users can focus on their core applications rather than having to worry about launching and scaling applications manually. For the orchestration aspects, AKS offers a few options, such as Docker, Swarm, Kubernetes, and Mesosphere DC/OS, which are shown in the following screenshot:
Another important aspect for any managed container platform is the functionality of a container registry where you can store master copies of different container images based on application stacks and configuration. For this, Azure offers Azure Container Registry (ACR), which is private registry for you to tag and upload images there.
Now, in order to enable CI/CD practices with the Azure Container Service, the steps are very similar to the ones described in the previous section around enabling CI/CD for Azure functions. At a high level, the following are the key steps and the flow to enable these practices:
- Store your application code in a code repository such as the Visual Studio Team Services Git repository. Apart from the core application code, this may also include Docker files and compose and deployment files, which will be needed to create Docker images and enable deployment as per various environment-specific requirements.
- Any time a code change is committed to the code repository, it triggers a continuous integration build process in VSTS and creates new Docker images, which are then stored in the Azure Container Registry.
- Once the new Docker images are released to the registry, it triggers a new release using VSTS, which can be gradually promoted from Dev, Test, UAT, and then Production.
- This release process is integrated with different orchestrators supported by AKS, which pull the latest Docker image from the container registry and push it out the running instances to bring up the latest version of the application.
As part of the preceding process, multiple customizations can be performed, like being able to run particular types of tests or integration with other systems, which can be again easily managed using VSTS-based CI/CD pipelines.