Containerisation

Topics Covered

• Evolution of Infrastructure
• Virtual Machines vs Containers
• Overview of Docker
• Origin of Docker
• How Docker Works
• Image vs Container
• Docker Repository & Docker Hub
• Docker Tags
• Core Docker Commands
• Dockerfile
• Container Orchestration (Kubernetes)
• Conclusion

1. Evolution of Infrastructure

Application deployment has evolved from Bare Metal to Virtual Machines, then to Containers,
and finally to Container Orchestration, improving efficiency, scalability, and speed.

2. Virtual Machines vs Containers

Virtual Machines virtualize hardware and run a complete operating system, making them resource-intensive.
Containers share the host OS kernel, making them lightweight, faster, and efficient with consistent environments.

3. Overview of Docker

Docker is a platform that allows developers to build, package, and deploy applications in containers,
ensuring consistency across all environments.

4. Origin of Docker

Docker was introduced in 2013 by Solomon Hykes, simplifying and accelerating container adoption.

5. How Docker Works

Docker uses a client-server architecture where the Docker Client sends commands to the Docker Daemon,
which builds, runs, and manages containers using a layered file system.

6. Image vs Container

An image is a read-only template containing application code and dependencies, while a container is a running
instance of that image. Multiple containers can be created from a single image.

7. Docker Repository & Docker Hub

Docker repositories store versioned images, and Docker Hub is a centralized public registry used to share
and manage container images.

8. Docker Tags

Docker tags are used for versioning images, such as node:18 or nginx:latest,
helping maintain consistency across deployments.

9. Core Docker Commands

Build Image

docker build -t <image-name> .

Run Container

docker run -d -p 80:80 <image-name>

List Running Containers

docker ps

List All Containers

docker ps -a

Pull Image

docker pull <image-name>

Push Image

docker push <image-name>

Stop Container

docker stop <container-id>

Start Container

docker start <container-id>

Remove Container

docker rm <container-id>

Remove Image

docker rmi <image-id>

View Logs

docker logs <container-id>

10. Dockerfile

A Dockerfile is a declarative script used to build Docker images by defining the base image,
dependencies, application code, and execution steps, ensuring consistent and repeatable builds.

11. Container Orchestration (Kubernetes)

Kubernetes manages containerized applications at scale by handling automated deployment, scaling,
load balancing, and self-healing.

12. Conclusion

Containerisation enables portability, scalability, and efficient resource utilization,
making it a core component of cloud-native and DevOps practices.