Question-36: What do you mean by Docker Multistage builds?

Answer: Using multistage builds, your Dockerfile can produce multiple images and you can consider each image as a stage. And artifacts from preceding image can be copied to the current image.

Question-37: What is the difference between public and private repository?

Answer: With public repository your submitted Docker image can be downloaded by anyone. If you are using private repository then it requires authentication and authorization for somebody to download the image created by you.

Question-38: If you want your image should be publicly available, does not require authentication to add in registry?

Answer: Even, you want your Docker Image should be available to public. It is requiring that you yourself authenticate before submitting the image to public registry.  And for that you can use “docker login” command. Docker Hub is the place where you want to start first.

Question-39: Which command you can use to publish your image in registry?

Answer: You can use “docker push” command.

Question-40: What does it mean, you have to use container specific API to set up container runtime?

Answer: You can use API from the Kubernetes to describe the way application should be deployed. However, this relies on the container runtime to set-up an application container and that can be done using container specific API which is native to target OS. For Linux it mean you have to configure cgroups and namespaces.