Build a containerized web application with Docker
Docker uses the operating system kernel of the host computer to power the container
Many vendors also support Docker in the cloud. For example, you can store Docker images in Azure Container Registry and run containers with Azure Container Instances.
In this unit, you’ll use Docker locally to build and run an image, then upload it to Azure Container Registry and run it in an Azure Container Instance
Docker images are stored and made available in registries. A registry is a web service to which Docker can connect to upload and download container images. The most well-known registry is Docker Hub, which is a public registry. Many individuals and organizations publish images to Docker Hub, and you can download and run these images using Docker running on your desktop, on a server, or in the cloud. You can create a Docker Hub account and upload your images there for free.
When you download and run an image, you must specify the registry, repository, and version tag for the image