What is Docker Engine?
- Docker Engine is the core of Docker.
- It uses server-client technology to create & run containers.
- Major components of Docker Engine:
I.A Command-Line Interface (CLI).
II.A REST API which specifies interfaces that programs can use to talk to daemon & instruct it what to do.
III.A server (Docker Daemon) which is a type of long-running program called dockerd process.
What is a Docker Image?
- A Docker image acts as a set of instructions to build a Docker container.
- An image is comparable to a snapshot in virtual machines.
- Images are created using docker build command.
- Docker allows you to create and share software using docker images.
What is Docker Container?
- Docker Container is a runnable instance of images.
- Through Docker API or CLI, we can create or delete a container.
- Containers are by default isolated from each other and their host machine.
What is Docker Registry?
- Docker registry is the place where Docker images are stored.
- Docker Hub is a public registry that anyone can access & configure images.
- With docker run or docker pull commands, can pull images from configured Registry.
- With docker push command, image will be pushed to the Registry.
- Registry can be on public or local repository.