Docker - Begginer 1

Docker

What, Docker?

• Opensource platform tool 
• Manages the containers
• Allow to build applications in a container with the libraries, binaried and dependencies
• run from anywhere

Why Docker?

• portability
• light weight OS
• fast delivery(impact of light weight os)
• Multiple isolated OS
• Resource optimization
• Continous development and testing

Architecture

• Docker Client
• Docker Host 
• Docker Hub(Registery)

Also Docker images, Docker containers, Dcker Network and storages are contains in the architecture.

Docker client is used to communicate with Docker hosts using Docker daemon is installed in Docker host. Clients are used to manage the Docker components and operations such as create, delete, pull, push, bulid, run etc. Docker client can connect to the Docker host remotly using REST API, UNIX sockets or using a network interface.

Docker hub(Registery) is used to pull and push Docker images
There are two types of docker hubs

• Docker Hub Online/Docker Hub - can use in a cloud and images can be used as Public and Private according to the preferences of the users.

• Docker Hub Offline/ Local Docker hub - stored images locally

Docker images are a templates for containers. They are small and light weight. Also they are easy to be deployed. Also they are similar to snapshots and template can be created after making containers and all the environment in the containers, similar to the vdi files after installing the packers for a virtual machine.

Docker container is the layer which does write and read in the Docker images. Also after implementation is done in Docker containers, the images can be created.

Docker Network is used to connect containers each other.

type of the networks are

• Bridge - default network if the network is not specified

• Host -  use to connect Docker host network

• None - to disable the network

• Overlay -  use to connect differentc containers hosted on different hosts or many

• Macvlan - Assign a MAC address to the container

Docker Storage

The data stored in Docker containers are removed when the Docker containers are removed. So the storage is used to store the data permanently.

Volumes, stored in the file system(/var/lib/docker/ ) and columes are manages by Docker. But Non-Docker processes should not modify these volumes.

Bind Mounts, stored in anywhere on the host system.

tmpfs mounts, stored in host system's memory only. and never written tot eh host system's filesystem

(All the Pictures and resources are downloaded and refered from Internet)