Presented Docker in 15 minutes with two of my classmates at school. Presentation covering topics: Virtualization Virtual Machines Container Technology (Docker) Docker Compose Docker Swarm The demo can be found at: https://github.com/DanishKhakwani/SimpleDockerDemo

2. Agenda
● What is Virtualization?
● What is Virtualization trying to solve?
● Traditional Virtualization
● What is Docker?
○ Docker vs. Virtual Machine
● Images, Containers and Registry
● Volume Mounting, Port Publishing, Linking
● Docker Compose
● Demo
● Docker Swarm
● Docker Use Cases

3. What is
Virtualization?
What is it trying to
solve?
- Many systems on top of a single
powerful hardware
- Consistency across
environments
- Changing one thing without
affecting the other

4. Traditional
Virtualization
Pros:
- More isolation
Cons:
- Heavy

5. Container Technology

6. Docker vs. VMs
Pros:
- Speed (faster to spin up)
- Lightweight
- Portability (size)
- Density (Layered System -
AuFS)
Cons:
- Less isolated

7. What is Docker?

8. Docker Engine

9. Architecture on Linux Platform

10. Architecture on Windows Platform

11. Docker Image
A snapshot of a Linux filesystem.
Example Docker commands that operate on images:
● images: List all local images
● tag: Tag an image
● pull: Download image from repository
● rmi: Delete a local image (will also remove intermediate images if no
longer used)

12. Docker Container
A running instance of an image.
Example Docker commands that operate on containers:
● ps -a: List all containers (including stopped)
● run: Create a container from an image and execute a command
in it
● rm: Delete a container
● exec: Run a new command in a running container

14. Docker Registry
● A registry that stores and delivers images
● Private Registries
○ Private to user or company
● Public Registries
○ Example: Official Docker Hub Registry (https://hub.docker.com/)
■ Pull images from existing repositories
■ Create your own repositories
■ Push images to your own repositories

15. Mount Volumes
● Shared folders
● docker run –it –v /host/dir:/container/dir ubuntu bash
○ /container/dirinside the container will correspond to /host/dir in the
host
● docker run –it --volumes-from container_name ubuntu bash
○ Run a new container with the same volumes as an existing one

16. Publish Port
● Map ports
● docker run -d -p 8080:80 nginx
○ Map container’s port 80 to host’s port 8080
○ Use the official Nginx image
■ Which is configured to automatically run Nginx inside a container
○ On host, can then browse to http://localhost:8080/ in a web browser to
see the website

17. Dockerfile
- Reusable Images in different
environments (stage, dev, prod)
- Layered Filesystem (AuFS)
- Domain Specific Language
FROM python:3.4
ENV PYTHONUNBUFFERED 1
RUN mkdir /code
WORKDIR /code
ADD . /code/
RUN pip install -r requirements.txt

18. Docker Compose
- Written in YAML
- Make microservice containers
behave like a single system

19. Docker Compose
version: '2'
services:
db:
image: postgres
web:
build: .
command: |
bash -c 'bash -s <<EOF
./wait-for-it.sh db:5432 &&
python myapp/manage.py makemigrations &&
python myapp/manage.py migrate &&
python myapp/manage.py loaddata myapp/initial.json &&
python myapp/manage.py runserver 0.0.0.0:8000
EOF'
volumes:
- .:/code
ports:
- "8000:8000"
depends_on:
- db

20. DEMO

21. Docker Swarm
- Clustering
- Scheduling
- Load Balancing
- Fault-tolerance
- Rolling updates

22. Docker Use Cases
● Consistent Environments
● Quick evaluation of software
● Microservices

23. Q/A