The document provides an overview of Docker fundamentals, including what Docker is, its architecture, common operations, and advantages. It begins by explaining that Docker is a container technology that packages code and dependencies together. Containers run atop the same OS kernel and utilize fewer system resources than virtual machines. The document then describes Docker's client-server architecture and underlying technologies like namespaces and cgroups that enable isolation. It also outlines common Docker commands and explains that Dockerfiles define container configurations.

1. Docker Fundamentals
Anshul Patel

2. Agenda
● What is OS Kernel?
● What is Virtual Machine(VM)?
● What is Docker?
● Docker Architecture
● Common Docker Operations
● What is Dockerfile
● Docker Advantages

3. What is OS
Kernel?
● Kernel is core part of Operating
system.
● Kernel controls everything in the
system.
● First program which is loaded
by Bootloader during the
system startup.
● Core Functionalities include:
○ Memory Management
○ Process Management
○ Input/Output
Management
Reference:
https://en.wikipedia.org/wiki/Kernel_(operating_system)

4. What is Virtual
Machine(VM)?
● VM is abstraction of physical
hardware.
● Abstraction is provided by piece
of software called Hypervisor.
● Each VM include the fully copy
of the corresponding Operating
System along with necessary
binaries and libraries.
● Scalable and Flexible than their
physical counterparts.
● Low performance than their
physical counterparts.
Reference:
https://www.packtpub.com/books/content/working-virtual-mac
hines

5. What is Docker?
● Docker is container technology.
● Containers are abstraction at
the app layer.
● Containers, packages code and
dependencies together.
● Different containers running on
the same machine, shares the
same OS kernel.
● Utilizes less system resources
compared to VM.
● Starts almost instantly.
Reference: https://www.docker.com/what-container
Docker Containers Virtual Machine

6. Docker
Architecture
● Docker Client: Provides API and CLI to
interact with docker
● Docker Daemon/Engine: Listens for
Docker API requests and manages
docker objects. (images, network,
storage, containers)
● Docker Registry: It stores docker
images.
Reference:
https://docs.docker.com/engine/docker-overview/#docker-architecture

7. Docker
Architecture
● Containerd: Industry standard
container runtime. It manages
the lifecycle from image to
container, execution,
supervision and networking.
● RunC: It is used by Containerd
for spawning and running
containers.
● Container-shim: Manages
headless containers. Once
initialized, RunC passes the
container handling to shim.

8. Docker Architecture – Underlying Technologies
● Kernel Namespaces: Docker uses it to provide process, network, filesystem,
etc isolation for each container.
● Kernel Control Groups: Docker uses it to enforce limit and constraints on
hardware resources. ( memory, cpu, i/o)
● Union Filesystem: Docker uses union filesystem for containers as it
lightweight and fast. (supports layering and CoW)
● Container Format: Docker combines namespaces, cgroups and UnionFS
into format called container format.

9. Docker Common CLI Operations
● Pulling and Listing Docker image
● Running and Listing Docker containers
● Stopping container and Removing Docker Container
● Mapping Host port with Docker container
● Mounting Host Directory/File on Docker container
● Checking Docker Container Logs
● Login into Docker Container
● Removing Docker Container Image
● Pushing to Docker Registry

10. Dockerfile
Reference: https://docs.docker.com/engine/reference/builder/

11. Docker Advantages
● Lightweight, Open and Secure
● Portable and efficient in comparison to VM
● Accelerates Developer Onboarding
● Empower Developer Creativity
● Eliminates Environmental Inconsistencies
● Ability to scale quickly
● Reduces time to market