[Roadmap] Backend Developer Roadmap: 13. Docker and Kubernetes

July 12, 2023

Backend Roadmap	Link
0. Roadmap	Roadmap
1. Internet	Internet
2. OS	Operating System
3. R-DB	Relational Database
4. API	API
5. Caching	Caching
6. Security	Web Security
7. Testing	Testing
8. CI/CD	CI/CD
9. Design	Design and Development Principles
10. Architecture	Architectural Patterns
11. Search Engines	Search Engines
12. OAuth	OAuth
13. Docker/K8s	Docker and Kubernetes

Docker

Docker is a conatiner technology: A tool for creating and managing containers

Container

A standardized unit of software
A package of code and dependencies to run that code (e.g. NodeJS code + the NodeJS runtime)
The same container always yields the exact same application and execution behavior. No matter where or by whom it might be executed.
Support for Containers is build into modern operating systems.
Docker simplifies the creation and management of such containers

We want reliability and reproducible environments

We want to have the exact same environment for development and production -> this ensures that is works exactly as tested
It should be easy to share a common development environment or setup with (new) employees and colleagues
We don’t want to uninstall and re-install local dependencies and runtimes all the time

Docker Containers		Virtual Machines
Low impac on OS, very fast, minimal disk space usage		Bigger impact on OS, slower, higher disk spaces uage
Sharing, re-building and distribution is easy		Sharing, re-building and distribution can be challenging
Encapsulate apps/ environments instead of “whole machines”		Encapsulate “whole machines” instead of just apps/ environments

Manual deployment of Containers is hard to maintain, error-prone and annoying (ene beyond security and configuration concerns)

Containers might crash or go down and need to be replaced -> Container health checks + automatic re-deployment
We might need more container instances upon traffic spikes -> Autoscaling
Incoming traffic should be distributed equally -> Load balancer

Using a specific cloud service locks us into that service.

You need to learn about the specifics, services and config options of another provider if you want to switch.

Just knowing Docker isn’t enough.

Kubernetes: An open-source system (and de-facto standard) for orchestrating container deployments

Using with Any Cloud Provider or Remote Machines (Kubernetes Configuration)
Extensible, yet standardized configuration: Standardized way of describing the to-be-created and to-be-managed resources of the Kubernetes Cluster (Cloud-provider-specific settings can be added)

It’s not a cloud service provider -> It’s an open-source project
It’s not a service by a cloud service provider -> It can be used with any provider
It’s not restricted to any specific (cloud) service provider -> It can be used with any provider
It’s not just a software you run on some machine -> It’s a collection of concepts and tools
It’s not an alternative to Docker -> It works with (Docker) containers
It’s not a paid service -> It’s a free open-source project

Therefore, Kubernetes is like Docker-Compose for multiple machines