Alexey Vasiliev

6+ years experience
- Linux and Databases administrator
- Web and Mobile developer (Ruby, Java, JavaScript, Objective-C, C/C++)
Open-Source developer
- WebP-ffi
- MongodbLogger for Rails
- Piro - Chrome extension for PivotalTracker
- SMTRails and SHTRails (shared templates for rails)
- SkypeKit for Ruby

Chef

Chef is an open-source systems integration framework built specifically for automating the cloud.

Why Chef?

Efficiency
Scalability
Reusing
Save money
Documentation

Why Chef?

Chef is like unit tests for your servers.

Ezra Zygmuntowicz

Main idea of Chef: Idempotence

Idempotence

It can safely be run multiple times. Once you develop your configuration, your machines will apply the configuration and Chef will only make any changes to the system if the system state does not match the configured state.

What doesn't Chef do?

"Magically" configure your server
Blindly reuse cookbooks and recipes
Monitor your servers or softwares
Undoing concept

Chef Types

Chef Solo
Chef Server
Hosted Chef (Chef Server by Opscode)

Terminology

Node
Chef Server
Chef Client
recipe
cookbook
role
run list
attribute

Knife

Chef

Knife is a powerful command-line interface (CLI) that comes with Chef.

Example for Chef Solo:

  gem install knife-solo

Main commands:

kitchen
prepare
cook
wash_up

Kitchen

Chef

Kitchen is a place where you build and store recipes. And cook!

  knife kitchen mychefrepo

The kitchen command simply takes a name of the directory to store the kitchen structure.


      mykitchen/
      ├── cookbooks
      ├── data_bags
      ├── nodes
      ├── roles
      ├── site-cookbooks
      └── solo.rb

Prepare & Cook

Chef

  knife prepare ubuntu@10.0.0.201

  knife bootstrap --template-file bootstrap.centos.erb -u root 10.0.0.201
  echo '{"run_list":[]}' > nodes/10.0.0.201.json

  knife cook ubuntu@10.0.0.201

That's it!

Librarian

Chef

  gem install librarian
  librarian-chef init
  librarian-chef install

Librarian

Chef

  $ cat Cheffile
  #!/usr/bin/env ruby
  site 'http://community.opscode.com/api/v1'

  cookbook 'nginx',
    :git => 'git://github.com/opscode-cookbooks/nginx.git'
  cookbook 'rvm'
  cookbook 'ruby_build'
  cookbook 'rbenv',
    :git => 'https://github.com/fnichol/chef-rbenv'
  cookbook 'postgresql',
    :git => 'git://github.com/opscode-cookbooks/postgresql.git'

Berkshelf

Chef

  gem install berkshelf
  berks install

Berkshelf

Chef

  $ cat Berksfile
  #!/usr/bin/env ruby
  site :opscode

  cookbook 'mysql'
  cookbook 'nginx', '~> 0.101.5'

Recipe

Chef

    ├── CHANGELOG.md
    ├── CONTRIBUTING
    ├── Gemfile
    ├── LICENSE
    ├── README.md
    ├── attributes
    ├── definitions
    ├── files
    ├── metadata.rb
    ├── recipes
    ├── templates
    └── test

Recipe definitions

Chef

        template "#{node[:nginx][:dir]}/sites-available/#{node[:app][:name]}.conf" do
          source "nginx.conf.erb"
          mode "0644"
        end
        nginx_site "#{node[:app][:name]}.conf"

        $ cat nginx.conf.erb
        upstream prod_unicorn {
          server unix:<%= node[:app][:web_dir] %>/shared/tmp/sockets/unicorn.sock fail_timeout=0;
        }
        server {
            listen 80 default;
            ...

Recipe execution

Chef

        "run_list": [
          "nginx[source]"
        ]

        include_recipe "nginx::source"

Simple example of own recipe

Chef

        ├── recipes
        │   └── default.rb
        └── templates
            └── default
                ├── database.yml.erb
                ├── nginx.conf.erb
                └── unicorn.rb.erb