Image tagging and versioning

Docker images use tags in order to provide different versions of the same image in the repository – each image tag corresponds to a given Docker image ID. Specifying tags for Docker images is often performed during an image build, but you can also add tags explicitly using the docker tag command:

docker pull mcr.microsoft.com/dotnet/core/sdk
docker tag mcr.microsoft.com/dotnet/core/sdk:latest mydotnetsdk:v1
docker tag mcr.microsoft.com/dotnet/core/sdk:latest mydotnetsdk:v2

In this example, we pulled the latest image tag (as it was not specified explicitly) of the .NET Core SDK and then tagged the image with the mydotnetsdk:v1 and mydotnetsdk:v2 tags in the local image cache. Now, it is possible to use these tags while performing operations on your local machine, like so:

docker run -it --rm mydotnetsdk:v1

Let's take a look at the latest tag, which is often used when working with Docker.