A quick introduction to Docker and Linux containers

1. A BEGINNER’S JOURNEY
Containers
Credits: http://bit.ly/1VKcNoZ
and Docker

2. Manuel de la Peña
Software Engineer @ Liferay Inc
Interested in: SW Engineering,
Coding, Testing, DevOps
Credits:http://bit.ly/1V8Hpzx

3. TheVM model
The Container model
Docker, Inc.
The High Level Picture
Credits: http://bit.ly/24xaXwK

4. Credits: http://bit.ly/1SP5iHw
It’s all about…
applications

5. APPLICATION
INFRASTRUCTURE
Credits: http://bit.ly/1OetMIn
• Dedicated Server
• Purchase order
• O.S. installs & licenses
• Rack positions
• Redundant power & network

6. VIRTUALISATION
TOTHE RESCUE
Credits: http://bit.ly/1WOfjJU
• KVM,VMWare, Xen
• Hypervisor with multiple
virtual machines
• VM’s looks, feels and
tastes as a physical
machines

7. THIS MODEL
IS UGLY… Credits: http://bit.ly/23pCASq

8. UGLY BECAUSE OFTHE O.S.
• The model is one app perVM and each
VM requires one O.S.
• O.S. only exists to facilitate the application
• Footprint (CPU, RAM, disk space)
• Licensing if needed
• More O.S. is not adding more Business
Value
Credits: http://bit.ly/23pCASq

9. Secure, isolated environment
Minimal O.S. service
Some service controls
Credits: http://bit.ly/1SP5iHw
It’s all about
applications

10. CONTAINERS
TOTHE RESCUE
Credits: http://bit.ly/23pIymw
• Run on Linux machines*
• An application runs in the
USER SPACE
• User Space: memory area
where application and some
drivers execute.

11. CONTAINER (OS-LEVEL)
VIRTUALISATION
• Container model tries to
run multiple applications
creating multiple user
spaces.
• Only one O.S. installed
• Share same instance of the
Linux kernel in the host.
Credits: http://bit.ly/23pIymw

12. MORE LIGHTWEIGHT
THANVM’S
Credits: http://bit.ly/23pIymw
Resources used before
we install the app
Faster and more portable

13. A single container
should run a single app
or a single process.
Once the process
of the container exits
so does the container.
Credits: http://bit.ly/23xrJWD

15. • Company under the technology/platform.
Previously DotCloud, a PaaS company.
• Docker&Containers = RedHat/Ubuntu&Linux Kernel.
• It’s a package you can get support for.

16. • They provide a very uniform standard
container runtime.
• Developers can code their applications in a local
docker environment and move them to AWS,
Azure, On-Premise.
• Think of Android Apps that run on tablet and phones.

17. • Internal project by Solomon Hykes, written in Go.
• Evolving to a platform:
• Image format
• Container Runtime (Docker Engine)
• Registry (Docker Hub)
• Clustering (Swarm)
• Service Discovery (Compose)
• Networking (libchan), etc.

18. FUTURE OF DOCKER
• Windows Containers
• Cannot create Windows
containers on Linux kernel, and
viceversa.
• Containers enforces
microservices architecture.
(single process inside single
container approach)

19. HIGH LEVEL PICTURE

20. Took days or weeks to load
Broken or rooted Goods
Global Trade was high Cost and Risk
THE IMPORT/EXPORT
NIGHTMARE

21. Development
Staging
Test Environment
Works on my Laptop!
APPLICATION
DELIVERY
Production

22. Malcolm P. MacLean, 1956
Inventor of containers
Saved 25% cost in
security and transport
Credits: http://bit.ly/1VQaocx

23. CONTAINERS AND
SHIPPINGYARDS
ARE EFFICIENT AND SAFE
STANDARD

26. THE SHIPPINGYARD
ANALOGY
• Shipping Yard —> Docker Engine (Daemon or
Runtime)
• Manifests —> Docker Images
• Containers —> Docker Containers

27. Engine, Images
and Containers
make application
delivery happen
Credits: http://bit.ly/1UEiX8Z

28. DOCKER ENGINE
(SHIPPINGYARD)
• Application infrastructure and runtime
dependencies standardised.
• Completely the same runtime environments from
docker-host to docker-host.
• De-facto industry standard for containers.

29. DOCKER IMAGES
(MANIFEST)
• Instructions on how to build containers (static definition with
data and metadata), likeVM templates.
• Its required to instantiate a container.
• Images can be categorised with tags, being latest the default.
• Maintainers tend to have the images as small as possible
with minimum packages installed, just the needed to provide a
functional runtime.

30. DOCKER CONTAINERS
• Running instances of images.
• Runtime.
• Linux machines*
• Container ID & Name

31. Run unchanged containers in your
local machine or in production
Time to production decreased
Credits: http://bit.ly/1UEiX8Z

32. OK, Docker engine, docker
images, and docker containers,
but…
Credits: http://bit.ly/1Zuy3Nv
Where do I get the images?

33. DOCKER REGISTRIES
• Images are inside repositories, categorised with tags.
• Repositories live inside a registry.
• Docker Hub is the default public registry of Docker.
• There are official (trusted) repos: Redis, Fedora, Ubuntu,
MongoDB…
• And non-official repos, from members of the docker
community.
• Private registries.

34. https://hub.docker.com/r/mdelapenya/liferay-portal/tags/

35. Security concern
Trust the containers you use, it
can contain malicious code
Credits: http://bit.ly/1UEiX8Z

36. CONTAINERS ARE GOINGTO
DESTROYVIRTUAL MACHINES
Credits: http://bit.ly/1rxYtmS