Docker is a software development platform for virtualization with multiple operating systems running on the same host. Docker container runs on top of the host’s operating system to improve efficiency and security when compared with the hypervisor. Docker is a client-server-based application.

Components of Docker

a)         Docker daemon – which is the server

b)         Docker Client

c)         Docker Images – Source code for containers

d)         Docker Registries – This is where docker stores images we build. There are private and public registries. The public registry is called docker hub

e)         Docker Container – Is the organizational unit of docker

2. Docker pause suspends all processes in the specified container while Docker unpause un-suspend all processes in the specified containers

3. Docker stop gracefully shut down container while Docker kill immediately stops/terminate containers

4. Docker Exec – executes new command / creates a new process in the container while Docker attach just connects to a running container using the container’s ID or name

5. Dockerfile Instruction – lists of commands a user could call on the command line to assemble an image

6. Entry Point specifies a command that will always be executed when the container starts. On the other hand, CMD defines default commands and/or parameters for a container.