This document introduces software containers and Docker. It defines containers as portable and isolated runtime environments for applications, sharing the same kernel as other containers. Docker is a toolset for creating and managing containers, with key components including the Docker Engine, images, and Hub registry. The document explains how Docker uses read-only layers and writable container layers to build images and run containers.

1. Playing in the
sandbox
Introduction to

2. 1. Intro

5. Dev 1 Dev 2 QA Server Production Cluster Public Cloud
Frontend Backend Messaging Persistance Analytics
?

6. Dev 1 Dev 2 QA Server Production Cluster Public Cloud
Frontend Backend Messaging Persistance Analytics
Software
Containers

7. “lightweight VMs”
Virtual Machines Software Containers
1 Virtual Machine = 1 GB
2 Virtual Machines = 2 GB
1 Container 1GB
2 Containers (still ~ 1GB)
less overhead,
faster start
shared OS
resources
Why not take VMs?
easier migration
Host Operating System
Infrastructure
Hypervisor
Guest OS
Bins/Libs
App 1
Guest OS
Bins/Libs
App 2
Guest OS
Bins/Libs
App 3
Host Operating System
Infrastructure
Docker Engine
Bins/Libs
App 1
Bins/Libs
App 2
Bins/Libs
App 3
Source: https://www.solidfire.com/blog/containers-vs-vms/

8. What are Software Containers?
portable, safe and isolated runtime for applications
share one kernel for multiple user spaces
no missing dependencies or wrong library versions
no platform compatibility issues (Linux kernel > 3.10, macOS > 10.10, Windows
Server 2016, Windows 10, Docker Toolbox for older versions)

9. 2. Docker

10. Docker
• toolset for creating, managing and deploying containers
• open source project, offers commercial support (partnering with IBM)
• Docker Client: Command line interface to access the engine (via REST)
• Docker Engine: Server application to run and manage containers (runs a daemon)
• Docker Registry: Publish and share images (public or private)
• built on top of Linux containment features:
• cgroups: limit resources, including the CPU, memory, block I/O and network
• namespaces: isolate an application's view of the operating environment

11. Docker
Source: https://www.datadoghq.com/docker-adoption/

12. Read-only layers that
represent filesystem
differences
Layers are stacked on top
of each other
Base for a container’s
filesystem
alpine:3.1
91e54dfb1189
d74508fb6632
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194.5 KB
3.456 MB
0 B
181.4 MB }
Read-onlylayers
Application
Image
Docker Basics: Images
Source: https://docs.docker.com/engine/userguide/storagedriver/imagesandcontainers/

13. Example: Build an image with a
> npm install
> copy . /app
> apt-get install nodejs
> CMD [“npm”, “start”]
alpine:3.1
91e54dfb1189
d74508fb6632
c22013c76729
c3a1f33e8a5a
194.5 KB
3.456 MB
0 B
181.4 MB
Docker Basics: Building Images
application

14. • Runnable instance of a Docker
image
• You can run, start, stop, move,
or delete a container.
• Running multiple containers
from one image only produces
very little overhead
Docker Basics: Running Containers
alpine:3.1
91e54dfb1189
d74508fb6632
c22013c76729
c3a1f33e8a5a
194.5 KB
3.456 MB
0 B
181.4 MB
Application Image
thin read/write layer
Container Layer

15. • new software distribution
channel for vendors
• community, official and private
images(450k images, 4B+
pulls)
• official images from Ubuntu,
Debian, mongoDB, Redis,
WordPress, Java, …)
• Automated builds
Docker Basics: Docker Hub
Source: https://www.docker.com/company

16. 3. Demo

17. Want to learn more?
Links
• Visit Docker: https://www.docker.com/
• Demo Project on GitHub: https://github.com/rafaelkonlechner/punsch-tracker
• Pokémon-GO on Docker: https://cloudplatform.googleblog.com/2016/09/bringing-Pokemon-GO-to-life-on-
Google-Cloud.html
Image credits:
• Forklift by Simon Child from the Noun Project (Creative Commons)
• Train by Roger Cook and Don Shanosky (Public Domain)
• Wooden box (Copyright http://www.jmpholdings.co.id/)
• Piano (Copyright http://www.uvi.net/)
• Barrel (Copyright cantinerallo.it)
• Bag (Copyright http://www.ivohaas.at/)
• Container (Copyright http://www.containersfirst.com.au/)