Deployment in a new Cloud Era

presentation about shipping and tooling

Created by Rach Belaid / @rachbelaid

Who I am.

• Python charmer
• Git Lover
• PostgreSQL Fan

I build web products and love learning something new.

Version controle matters!!

It keeps the history of the application.

What about servers?

How do I version them? Unfortunately I cannot do:

git reset --hard <previous>

What is an application?

Is it just code?

Or, does it include all its components?

This is a talk about shipping release.

Warning: There is no silver bullet for all cases.

What's a Good release?

• Self Contained
• Easy to rollback
• Fast to deploy
• Easy to upgrade (less legacy)
• Easy to duplicate
• Testable in parallel

What's the cloud?

• Buzzword
• Flexible resources
• More resources on demande
• Pay for what you use

What to ship then?

• Source Code
• Python package
• Distribution Package
• LXC
• Images

Tools

• Python Wheels
• FPM
• Docker
• Packer

Use tools or contribute but don't reinvent the wheel ;)

Python Wheels

PEP 427 - A wheel is a ZIP-format archive.

Example: Create Wheels

pip install wheel
pip wheel --wheel-dir=/local/wheels -r requirements.txt
pip wheel --wheel-dir=/local/wheels ./app

Example: Install Wheels

pip install --use-wheel --no-index --find-links=http://myfancyurl/

Downsides

• Not self-contained.
• Just code.
• Not easy to rollback.
• Portability.

Distro Package via FPM

Fundamental Principle:

Example: Create Package

fpm -s python -t deb ./app/setup.py
fpm -s dir -t deb app_folder_with_venv/

Upsides

• Easy to rollback.
• Make migration easier.
• Wrap your dependencies.

Downsides

• Not self-contained (enough).
• Just code.
• Platform dependant.

What about the big picture

Application are more complex and not just code

they have dependencies!!

• Redis
• Postgres
• System Libs

Configuration managment?

I love sensible configuration managment

• Salt
• Ansible

But they are not easy to rollback

... even if you keep it in a VCS. It's not enough.

Immutable servers

From

Credit: Martin Fowler blog post on Immutable Server

Immutable servers

To

Credit: Martin Fowler blog post on Immutable Server

Versionning Server State!

LXC, made easy with Docker

What's docker

Docker, the Linux Container Runtime, an application to pack, ship and run any application as a lightweight container

What container matter

• Content Agnostic
• Hardware Agnostic
• Content isolation
• Automation
• Separation of duties

Get Started

git clone https://github.com/dotcloud/docker.git
cd docker
vagrant up
vagrant ssh
sudo docker

Docker Awesomeness

• Versionning
• Push / Pull
• Remote/Private Registery
• Logs
• Diff
• REST API

Downsides

• Kernel version
• Auto-scalling

Images, made easy via Packer

What's packer

Simple JSON to describe 3 steps:

• Provisioning (shell, files, Salt, Chef)
• Build (AWS, DigitalOcean,...)
• Post-Process (Vagrant, Compress)

Examples

{
  "builders": [{
    "type": "amazon-ebs",
    "region": "us-east-1",
    "source_ami": "ami-e50e888c",
    "instance_type": "t1.micro",
    "ssh_username": "ubuntu",
    "ami_name": "packer-example {{timestamp}}"
  }],
  "provisioners":[
  {
	"type": "shell",
	"inline": ["echo 'I can chain Provisioners'"]
  },
  {
	"type": "salt-masterless",
	"bootstrap_args": "git v0.16.0",
	"local_state_tree": "path/to/states",
	"local_pillar_roots": "path/to/pillar"
  }]
}

What to use where

There is no rules. They all can play well together (with a shoehorn)

Wheels

FPM

Docker

Packer

A Final Word

Have Fun and Pick your tools.