GnoseedGnoseed
Start Learning
DevOps · 5 modules

Docker Fundamentals

Containerization explained from first principles. Learn images, the Dockerfile, volumes, networking and Docker Compose — the foundation for Kubernetes and modern deployment — remembered with spaced repetition.

Plant your first seed See sample questions
practice cards
62
practice cards
per day
~10 min
per day
level
Beginner
level
modules
5
modules
About this topic

What is Docker?

Docker packages an application together with everything it needs to run — code, runtime, libraries — into a portable image. Run that image and you get a container: an isolated, reproducible process that behaves the same on your laptop and in production. No more "works on my machine".

This track covers the building blocks: the difference between images and containers, writing a Dockerfile, persisting data with volumes, connecting containers over networks, and orchestrating multi-container apps with Docker Compose.

It uses spaced repetition so the commands and concepts stick — and it is the natural foundation before Kubernetes, which orchestrates containers at scale.

What you'll learn

5 modules, seed to bloom

Each module is a set of practice cards — 62 in total. Answer, review, and watch your knowledge grow from seed to full bloom.

Containers & Images

Docker fundamentals — containers, images, layers, lifecycle, and registries

13 cards

Dockerfile

Building images — instructions, layers, caching, multi-stage builds, and optimization

12 cards

Volumes & Storage

Data persistence — volumes, bind mounts, tmpfs, backup, and sharing

10 cards

Networking

Container communication — drivers, CNM, DNS discovery, port mapping, and network isolation

15 cards

Docker Compose

Multi-container apps — services, networking, volumes, environment, and lifecycle

12 cards
Try before you plant

Sample questions

A taste of the real cards. Pick an answer, then reveal the explanation.

Sample · Docker Fundamentals

What is Docker?

  • AAn open-source platform that packages applications into containers — isolated units sharing the host OS kernel
  • BA hypervisor that creates lightweight virtual machines — each running its own kernel on shared hardware
  • CA configuration management tool that automates server provisioning — similar to Ansible or Puppet
  • DA cloud hosting service that deploys applications to managed servers — abstracting infrastructure automatically
Sample · Docker Fundamentals

What is a Dockerfile?

  • AA text file containing ordered instructions that Docker reads to automatically build an image layer by layer
  • BA YAML configuration file that defines multiple services, networks, and volumes for a multi-container application
  • CA binary manifest embedded inside every Docker image that records metadata about the build environment used
  • DA shell script that Docker executes inside a running container to install packages and configure the application
Sample · Docker Fundamentals

What are the three types of mounts available in Docker?

  • AVolumes, bind mounts, and tmpfs mounts — each serving different persistence and performance needs
  • BBlock mounts, object mounts, and network mounts — each mapped to a different cloud storage backend
  • CRead-only mounts, read-write mounts, and overlay mounts — each defining a different permission level
  • DHost mounts, container mounts, and shared mounts — each scoped to a different isolation boundary
Sample · Docker Fundamentals

What is Docker Compose used for?

  • ADefining and running multi-container applications using a single YAML file to configure all services, networks, and volumes
  • BBuilding optimized Docker images by combining multiple Dockerfiles into a single multi-stage build pipeline
  • COrchestrating containers across a cluster of machines with automatic scaling, load balancing, and failover
  • DManaging Docker daemon configuration on multiple hosts by synchronizing registry credentials and settings
How Gnoseed works

Learn it once, keep it for good

1

Answer a question

Each card is one practical concept with multiple options. Pick what you think is right.

2

Get the full answer

See the correct option plus a clear explanation, and a link to deeper docs when one is available.

3

Review at the right time

A spaced-repetition engine (SM-2 or FSRS) resurfaces each card just before you would forget it.

Why learn this

Why Docker is worth your time

The unit of modern deployment

Containers are how software ships today. Docker fluency is table stakes for backend and DevOps work.

Kill "works on my machine"

Reproducible images mean the same behaviour on every laptop, CI runner and server.

The on-ramp to Kubernetes

Kubernetes orchestrates containers — understanding Docker first makes it click far faster.

Faster local development

Spin up databases and services in seconds with Compose instead of installing them by hand.

FAQ

Common questions

Do I need DevOps experience? +

No. The track starts from what an image and a container actually are and builds up from there.

How long does it take? +

About 10 minutes a day. Spaced repetition means short, frequent sessions beat long cramming, so the commands and concepts stick.

Is it free? +

Yes, completely free. No registration or credit card is required, and all your progress is stored locally in your browser.

Should I learn Docker before Kubernetes? +

Yes. Kubernetes orchestrates containers, so a solid grasp of Docker makes the Kubernetes tracks much easier.

Ready to master Docker?

Plant your first seed today. Ten minutes a day is all it takes to grow real, lasting container skills.

Start learning free