Automated configuration management for small teams; Chef, Capistrano, Cuoco

7/30/2019 Automated configuration management for small teams; Chef, Capistrano, Cuoco

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Add some Chef to yourCapistrano

Moving towards automated server configuration with a small team

@leonid_shevtsov for @RubyGarage, 2012Thursday, December 6, 12


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About me

Im Leonid Shevtsov, http://l-s.me

I code Ruby and Javascript at Railsware http://railsware.com

Ive configured and deployed tens of applications.

(though no 100-server ones).

Thursday, December 6, 12
http://railsware.com/http://railsware.com/http://l-s.me/http://l-s.me/


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Why bother with CM tools

You have to manage an infrastructure of hundreds of servers.



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You have to manage an infrastructure of hundreds of servers.



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Dont Use Manual ProcedureThe Pragmatic Programmer



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Make implicit knowledge explicit;

Turn configuration into code;

Make configuration reusable.



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What is server configuration

Imperatively: a list of commands executed by the sysop.

Declaratively: a list of modifications of the files on the server.



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Where is the server configurati

Best case scenario: in a log file/readme maintained by the syso

Worst case scenario: just in the file modifications.



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Make implicit knowledge expli

All configuration in one place;

Indicate what options are customized/important;

What if the sysadmin (or the server guy) gets sick (or fired)

Discourages (though doesnt prohibit) cowboy debugging;



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Turn configuration into code

Programmers understand code.

Code can be diffed

Code can be merged

You can collaborate on code

You can share code between projects

You can refactor code



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Make configuration reusable

Scaling is a matter of refactoring;

Reallyidentical staging environment;

Test entire stack on a virtual machine;



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Automated server configuratiothe future



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Chef



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What is Chef?

A framework to build server configuration scripts powered byand JSON.

No more powerfulthan shell script, but much more effective.

Encapsulates common configuration patterns into resources.



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user app_name do

home "/home/#{app_name}"

supports :manage_home=>true

end

directory "/home/#{app_name}/apps/#{app_name}"do

owner app_name

group app_name

mode 0700

recursive true

end

# nginx site record

template "/etc/nginx/sites-available/#{app_name}"do

source "nginx_site.erb"

variables

:app_name=> app_name,

:server_name=> params[:server_name],:alternate_names=>Array(params[:alternate_names])

end

execute "ln -s /etc/nginx/sites-available/#{app_name} /etc/nginx/sites-enabled/#{app_name}

creates "/etc/nginx/sites-enabled/#{app_name}"

notifies :reload, 'service[nginx]'

end



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Push vs Pull

Pull configuration - suitable for major web sites

Servers update configuration automatically based on central

Requires infrastructure

Push configuration - suitable for less than major sites

You update configuration manually on demand

Natural next step from Capistrano



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Cuoco

Capistrano can connect to and run commands on your server

Chef Solo can configure your server if its already there;

Lets use them together!

https://github.com/leonid-she

https://github.com/leonid-shevtsov/cuocohttps://github.com/leonid-shevtsov/cuoco


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How to add Chef to Capistra

Capistrano should already have servers and roles

Add Cuoco to your project

Add a config/chef directory

Start cooking!

To run Chef, run cap cuoco:run_roles or just cap deploy:setup



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To bootstrap & run Chef, run cap cuoco:update_configuration

Works with capistrano multistage!

Works with host & role filters!

Servers pick up roles from Capistrano configuration



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How do I start?



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Requirements

Some experience with manual server configuration.

Some experience with Ruby.

A couple of days of free time.



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https://github.com/leonid-shevtsov/cuoco_starter_kit

Setup a virtual machine for development.

Describe what you are already doing.

DONT overspecify & DONT fix what is not broken.

DONT use a cookbook just because it exists.

Start small

https://github.com/leonid-shevtsov/cuoco_starter_kithttps://github.com/leonid-shevtsov/cuoco_starter_kit


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Questions? Comments?

[email protected] to RailsWare http://railsware.com

mailto:[email protected]:[email protected]:[email protected]:[email protected]:[email protected]

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Automated configuration management for small teams; Chef, Capistrano, Cuoco