Docker Day 2 – Docker Architecture & Its Core Components.

Components of Docker:

1. Docker Daemon:

• (Docker daemon runs on the host OS). It is responsible for running containers to manages docker services.

• Docker daemon can communicate with other daemons.

2. Docker Client:

• Docker users can interact with docker daemon through a client (CLI).

• Docker client users commands (CLI) and Rest API to communicate with the docker daemon.

• when a client runs any server command on the docker client terminal, the client terminal sends these docker commands to the docker daemon.

• It is possible for docker client to communicate with more than one daemon.

3. Docker Host:

• Docker host is used to provide an environment to execute and run applications. It contains the docker daemon, images, containers, networks & storages.

4. Docker Registry/Hub:

• It manages & stores the docker images.

• These are two types of registries in the docker:

  1. Public Registry: Public registry is also called as docker hub.

  2. Private Registry: It is used to Share images within the enterprise.

5. Docker Images:

• These are the read only binary templates used to create docker Containers.

• Single file with all dependencies & configuration required to run a Program.

• ways to create an images:

  1. Take image from docker hub.

  2. Create image from docker file.

  3. Create image from existing docker containers.

3. Docker Container:

• Container hold the entire packages that is needed to run the application.

• In other words, we can say that the image is a template and the container is a copy of that template.

• Container is like a virtual machine.

• Images become container when they run on docker engine.