This document discusses application deployment as system state using configuration management tools like Chef. It describes how tools like Chef allow you to declaratively define system resources like users, packages, and applications. Chef recipes and cookbooks can be used to provision, configure, and integrate application code and dependencies. Roles in Chef describe nodes and contain recipes. Tools like Fabric, Capistrano, and chef-deploy can be used to deploy application code changes to servers defined through roles in Chef.

1. Application Deployment is System State
Joshua Timberman
@jtimberman
joshua@opscode.com
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2. % whoami
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5. Who are you?
• Developers?
• System administrators?
• DevOps?
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6. System State
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7. Configuration Management
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8. System Integration
http://www.flickr.com/photos/opalsson/3773629074/
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9. WAT?
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10. n-Tier Infrastructure
Load Balancer
App Server { { App Server
•
•
•
Provision
Configure
Integrate
Database Master
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12. We're hiring!
opscode.com/careers/
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13. Resources
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14. Declarative interface to
system resources
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15. user "django_app" do
shell "/bin/false
comment "Django App User"
system true
action :create
end
package "python" do
action :install
end
python_pip "gunicorn" do
action :install
end
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16. Describe *what*.
Not how.
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17. def install_package(name, version)
package_name = "#{name}=#{version}"
package_name = name if @is_virtual_package
run_command_with_systems_locale(
:command => "apt-get -q -y
#{expand_options(@new_resource.options)}
install #{package_name}",
:environment => {
"DEBIAN_FRONTEND" => "noninteractive"
}
)
end
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18. package “python”
{ yum install python
apt-get install python
pacman sync python
pkg_add -r python
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19. Recipes
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20. Ruby Internal Ruby DSL Ruby
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21. def method_missing(method_symbol, *args, &block)
return "lol method_missing"
end
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22. user "django_app" do
shell "/bin/false
comment "Django App"
system true
end
package "python"
python_pip "gunicorn" do
action :install
end
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23. Cookbooks
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24. opscode/cookbooks/python
├── README.md
├── attributes
│ └── default.rb
├── metadata.rb
├── providers
│ ├── pip.rb
│ └── virtualenv.rb
├── recipes
│ ├── default.rb
│ ├── package.rb
│ ├── pip.rb
│ ├── source.rb
│ └── virtualenv.rb
└── resources
├── pip.rb
└── virtualenv.rb
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25. Roles
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26. Roles describe nodes.
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27. name "django_cms"
description "django app app server"
run_list(
"recipe[mysql::client]",
"recipe[application]"
)
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28. Roles contain recipes
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29. name "base"
description "All nodes have the base role"
run_list(
"recipe[zsh]",
"recipe[sudo]",
"recipe[apt]",
"recipe[git]",
"recipe[build-essential]"
)
override_attributes(
:authorization => {
:sudo => {
:users => ["ubuntu"],
:passwordless => true
}
}
)
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30. Application Deployment
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36. Build your own
• Let's be realistic.
• You own your availability.
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37. Application Deployment vs...
• Configuration management
• Ad-hoc system administration
• Going against policy
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40. Package management
• Rpm
• Deb
• Pkgsrc
• Gems
• Eggs
• Not a solved problem.
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41. git "/srv/django_app" do
repository "git://github.com/me/django_app.git"
reference "master"
action :sync
end
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42. Fabric
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43. Capistrano
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44. chef-deploy
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45. deploy_revision[/srv/django_app]
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46. deploy_revision "/srv/django_app" do
revision "2.0.17"
repository "git://github.com/me/django_app.git"
user "django_app"
group "www-data"
before_migrate do
requirements_file = "#{release_path}/requirements.txt"
execute "pip install -r #{requirements_file}" do
cwd release_path
end
end
action :deploy
end
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47. Ad-Hoc Deployment
• knife ssh
• capistrano
• fabric (use pychef!)
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48. require 'chef/knife'
require 'chef/search/query'
Capistrano::Configuration.instance.load do
Chef::Knife.new.configure_chef
def chef_role(name, query = "*:*", options = {})
attr = options.delete(:attribute) || :ipaddress
nodes = Chef::Search::Query.new.search(:node, query)
[0].map {|n| n[attr] }
role name, *nodes, options
nodes
end
end
https://github.com/cramerdev/capistrano-chef
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49. from fabric.api import env, run, roles
from chef.fabric import chef_roledefs
env.roledefs = chef_roledefs()
@roles('web_app')
def mytask():
run('uptime')
http://pychef.readthedocs.org/en/latest/fabric.html
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50. Further Resources
• https://us.pycon.org/2012/schedule/
presentation/286/ (Noah Kantrowitz)
• http://wiki.opscode.com/display/chef/
Build+a+Django+Stack
• http://community.opscode.com/
cookbooks/application
• http://pychef.readthedocs.org/en/latest/
index.html
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51. Questions?
Joshua Timberman
joshua@opscode.com
@jtimberman (twitter, github)
lists.opscode.com
irc.freenode.net/chef
http://www.flickr.com/photos/oberazzi/318947873/
Wednesday, February 22, 12