An introduction to Docker

1. Hello, Docker!
An Introduction to Docker
Michael K. Essandoh

2. Michael Kwesi Essandoh @mexcon_mike
● Senior Software Engineer, ANDELA
● Director, TAISE
● Technical Consultant
● Ex: Petra Trust, VasSoft, Bsystems Limited
● .NET Fanatic

3. Outline
● What is DevOps?
● What is Docker?
● Containers vs VM
● Advantages of Docker
● Concepts
● General Guidelines
● Honourable Mention
● Resources
● QA
● DEMO

4. What is DevOps?
● A set of practices that combines software development (Dev) and IT (Ops) to
shorten the systems development life cycle while delivering features, fixes,
and updates frequently.
● Combining the right tools and culture to innovate rapidly
● DevOps is a culture
○ Agile principles
○ Error tolerance
○ Post mortems
● You can’t buy DevOps

5. What is Docker?
● Containers
○ Decouple applications (and their environments) from operating system
○ Virtualizes user space
○ More lightweight and portable compared to HyperVisor based virtualization
○ Go to option for microservice architecture
○ Ephemeral storage by default*
● Docker
○ Development tool and runtime environment for containers
○ Released March 13, 2013
○ Runs on Linux, MacOS and Windows
○ Alternatives: lxc, rkt, containerd*

6. Containers vs VM
Twistlock

7. Advantages of Docker
● Shorten development time
● Portable
● Standardization
● Minimal resource overhead
● Isolation
● MicroService architecture

8. Docker Concepts
● Dockerfile
○ Set of instructions or specifications that define the
structure of a container
● Image
○ Read-only templates
○ Static specification of what a container should be at
runtime
● Registry
○ Storage and distribution of images
○ Can be private
○ Local, DockerHub, Quay, AWS ECR, Red Hat
Container Catalog etc
Twistlock

9. General Guidelines
● Follow the Twelve-Factor App guidelines
● Keep images as small as possible
● Databases
○ Be careful. Especially in production
○ Caches - Memcache, Redis
● Security
○ Use trusted images from trusted sources
○ Code defensively
○ Don’t run as root

10. Honourable Mention: Kubernetes (k8s)
● Orchestration engine
● Initial release: 7 June 2014
○ Built by Google, mid-2014
○ Handed over to CNCF
● Cluster
○ Control
○ Data
○ Workers
● Competition
○ Docker Swarm
○ Mesosphere
○ Cattle (Rancher)
○ Portainer*
● k3s

11. Resources
● The Twelve Factor App
● Docker Docs
● Landscape CNCF
● Gists (BlitzinBuffalo)

12. QA

13. DEMO

14. The End
To God Be The Glory