Docker Course by Oleksandr Kovalov (JS developer at Binary Studio).

1. Docker
Academy PRO

2. Course’s
Agenda
Introduction to Docker
Containerization Basics
Orchestration Basics
Miscellaneous

3. Today’s
Agenda
What is containers?
Challenges & Solutions
How it works?

4. What is Docker?
Docker is an open platform that helps companies build, ship and run their
applications everywhere.

5. Evolution of IT
Earlier
● Thick client
● Well defined
stack
● Monolith
infrastructure
Today
● Thin client
● Many different
services
● Running on
different set of
resources

6. Static website
UserDB
API
Web Frontend Queue
Redis + Redis-sentinel
Node.js + Express + Mongoose
MongoDB
Webpack + React + Redux
nginx + bootstrap
Development VM
QA server
Public cluster
Production server
Contributors laptop
Customer datacenter

7. Cargo transport pre 1960

8. Matrix from hell

9. Solution

10. Linux Container (LXC)

11. cgroups - Linux kernel feature that limits, accounts for,
and isolates the resource usage (CPU, memory, disk I/O,
network, etc.) of a collection of processes.
namespaces - feature of the Linux kernel that isolates
and virtualizes system resources of a collection of
processes (pid, mnt, net..)
Linux Containers - operating-system-level virtualization
method for running multiple isolated Linux systems
(containers) on a control host using a single Linux kernel.
LXC combines the kernel's cgroups and support for
isolated namespaces to provide an isolated environment
for applications.

12. High level approach: lightweight VM
● own process space
● own network interface
● can run stuff as root
● can have own sbin/init

13. Low level approach: chroot on steroids
● can also not have its own sbin/init
● container = isolated process(es)
● share kernel with host
● no device emulation

14. Separation of concerns
Inside:
● code
● libs
● package manager
● app
● data
Outside:
● logging
● remote access
● network configuration
● monitoring

15. Build once - run everywhere!
Linux containers is units of software development
● run everywhere
○ regardless of kernel version
○ regardless of host distro
○ BUT container and host architecture must match
● run anything
○ if you can run it on host - you can run in the container
○ e.g. if it can run on Linux kernel, it can run

16. VMs vs Containers

17. Virtualization
Advantages:
● Multiple OS on same machine
● Easy maintenance and recovery
● Lower total cost of ownership
Disadvantages:
● Multiple VMs Lead to Unstable performance
● Hypervisors are not as efficient as host OS
● Long boot process

18. Containerization
Advantages over virtualization:
● Containers on same OS kernel are lighter
and smaller
● Better resource utilization
● Short boot-up process

19. Resource/Memory Utilization
16Gb 3Gb
2Gb
1Gb
4Gb
4Gb2Gb
16Gb 3Gb
4Gb
2Gb
VM Containers
7 Gb of Memory blocked and
cannot be used for new VMs

21. Containerd - industry-standard container runtime
with an emphasis on simplicity, robustness and
portability. It is available as a daemon for Linux and
Windows, which can manage the complete container
lifecycle of its host system: image transfer and
storage, container execution and supervision, low-
level storage and network attachments, etc..
runC - CLI tool for spawning and running
containers according to the OCI (Open Container
Initiative) specification.

22. What is Docker? #2
Docker is containerization platform which packages your application and all its
dependencies together in the form of containers so as to ensure that your
application works in the same way in any environment be it Development or
Test or Production

23. Why Docker?
● Isolation
● Lightweight
● Simplicity
● Workflow
● Community

24. Community

25. Community

26. Docker Adoption

27. Docker Adoption

28. Docker Adoption

29. Official Docker Images
https://hub.docker.com/explore/?page=1

30. Hello World!
$ docker run hello-world

31. Any questions?

32. The end
for today :)