How to containerize your monolith and/or microservices using Docker

Anton Antonov

https://github.com/syndbg/

https://www.linkedin.com/in/syndbg

Questions that are going to be addressed:

• What's Docker?
• What's really Docker?
• Docker container vs Virtual machine - what's better?
• How to create a Docker container?
• What's Docker-Compose?
• What's Docker-Machine?
• How to orchestrate services using Docker-compose
• How to run Hype CRM, Picard, Sidious in containers and every modern OS (incl. Windows)?

What's Docker?

It's actually a company that was previously called dotCloud.

It started off as a side-project and was only open-sourced recently in 2013.

What people commonly call Docker is actually the Docker Engine

What's Docker Docker Engine?

The Docker Engine is a:

• lightweight container runtime
• robust tooling that builds and runs your container.

What's Docker Docker Engine?

Docker Engine allows you to package up application code

and dependencies together in an isolated container

that share the OS kernel on the host system.

The in-host daemon communicates with

the Docker Client to execute commands to

build, ship and run containers.

What's really Docker 

Docker Engine?

Docker Engine is really an extension of the

Linux Containers (LXC in short) capabilities.

What's really Docker 

Docker Engine?

It provides a high-level API that provides a lightweight

virtualization solution to run processes in isolation.

What's really Docker 

Docker Engine?

It's written in Go (therefore I love it) and also utilizes cgroups and the Linux kernel itself.

What's really Docker 

Docker Engine?

Since it's based on LXC it does not include a separate Operating System (OS)

Docker container vs Virtual Machine

- what's better?

Here's a single Linux OS running several Docker containers - APP 1, APP2, APP3

Docker container vs Virtual Machine

- what's better?

Here's a single Linux OS running several VMs including - APP 1, APP2, APP3

Docker container vs Virtual Machine

- what's better?

Docker containers enable:

• Portable deployment across machines - you can transfer images quickly into other Docker-enable Linux hosts
• Versioning (more further in the presentation)
• Component reuse - using prebuilt images or creating base images and reusing them
• Shared libraries - using community build images from the official Docker Hub 
• Read even more at https://docs.docker.com/engine/faq/#/how-do-containers-compare-to-virtual-machines

How to create a Docker container

# Dockerfile
# Read more about Dockerfile syntax
# at https://docs.docker.com/engine/reference/builder/
FROM docker/whalesay:latest

RUN apt -y update && apt install -y fortunes

CMD /usr/games/fortune -a | cowsay

docker build -t docker-whale .

1. Create a Dockerfile that describes what your container wants to have. File syntax:

3. Run a Docker container using the prebuilt Docker image

docker run docker-whale

2.  Build a Docker image by using the Dockerfile

How to create a Docker container

Now a more "complex" container that communicates with another container.

Container 1: Sinatra Application

Container 2: Postgres DB