Chef.md

🧑‍🍳 Chef Cheat Sheet

📘 Introduction

Chef is a configuration management tool written in Ruby and Erlang. It automates the process of configuring, deploying, and managing servers and infrastructure.

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🟢 Beginner Level

🔹 Key Concepts

• Node: A machine (physical/virtual) managed by Chef.
• Cookbook: A collection of recipes and other config files.
• Recipe: The fundamental unit for configuration — contains Ruby code to define resources.
• Resource: A statement of configuration like package, service, file, etc.
• Runlist: A list of recipes/roles applied to a node.

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🍳 Chef Commands

🟢 Beginner Commands (Click to Expand)

🔹 Check Version

chef --version

🔹 Generate Cookbook

chef generate cookbook my_cookbook

🔹 Generate Recipe

chef generate recipe my_cookbook default

🔹 Run Chef Client (Local Mode)

chef-client --local-mode --runlist 'recipe[my_cookbook]'

🔹 Validate Ruby Syntax

ruby -c recipes/default.rb

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🟡 Intermediate Commands (Click to Expand)

🔹 Knife Bootstrap Node

knife bootstrap <IP_ADDRESS> -x user -P password --node-name node1

🔹 Upload Cookbook to Server

knife cookbook upload my_cookbook

🔹 Show Node Information

knife node show node1

🔹 Run Chef Client on Remote Node

knife ssh 'name:node1' 'sudo chef-client' -x user

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🔴 Advanced Commands (Click to Expand)

🔹 Search Nodes or Data Bags

knife search node 'role:web'
knife data bag show users

🔹 Edit Node or Role

knife node edit node1
knife role edit webserver

🔹 Generate Role or Environment

chef generate role webserver
chef generate environment dev

🔹 Upload Roles/Environments

knife role from file roles/webserver.rb
knife environment from file environments/dev.rb

🔹 Test Cookbook (ChefSpec, InSpec)

chef exec rspec
chef exec inspec exec test/integration/default

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🔹 Chef Setup

# Install Chef Workstation
curl -LO https://packages.chef.io/files/stable/chef-workstation/latest/el/7/chef-workstation-*.rpm
sudo rpm -Uvh chef-workstation-*.rpm

# Verify installation
chef -v

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🔹 Create a Cookbook

chef generate cookbook my_cookbook
cd my_cookbook

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🔹 Basic Recipe

# recipes/default.rb
package 'nginx'

service 'nginx' do
  action [:enable, :start]
end

# Run recipe on local machine (Test Kitchen or chef-run)
chef-run 'localhost' my_cookbook

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🔹 Common Resources

Resource	Example
package	package 'nginx'
service	service 'nginx' { action [:start, :enable] }
file	file '/etc/motd' { content 'Hello Chef' }
user	user 'deploy' { shell '/bin/bash' }

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🟡 Intermediate Level

🔸 Attributes

# attributes/default.rb
default['my_cookbook']['greeting'] = 'Welcome to Chef!'

# Use in recipe
file '/etc/motd' do
  content node['my_cookbook']['greeting']
end

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🔸 Templates

Templates are ERB files used to manage config files.

# generate template
mkdir templates/default
touch templates/default/index.html.erb

<!-- templates/default/index.html.erb -->
<h1>Hello <%= node['hostname'] %>!</h1>

# recipes/default.rb
template '/var/www/html/index.html' do
  source 'index.html.erb'
end

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🔸 Data Bags

# Create data bag and item
knife data bag create users
knife data bag from file users user1.json

// users/user1.json
{
  "id": "user1",
  "uid": "1001",
  "shell": "/bin/bash"
}

# Use in recipe
user_data = data_bag_item('users', 'user1')

user user_data['id'] do
  uid user_data['uid']
  shell user_data['shell']
end

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🔸 Roles

# Create role file
knife role create webserver

{
  "name": "webserver",
  "run_list": [
    "recipe[my_cookbook::default]"
  ]
}

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🔸 Environments

Used to manage differences between dev, test, prod.

# Create environment
knife environment create dev

{
  "name": "dev",
  "default_attributes": {
    "my_cookbook": {
      "greeting": "Welcome to Dev Environment"
    }
  }
}

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🔴 Advanced Level

🔹 Custom Resources

# inside cookbooks/my_cookbook/resources/hello.rb
resource_name :hello

property :name, String, name_property: true

action :create do
  file "/tmp/#{name}" do
    content "Hello, #{name}!"
  end
end

# recipes/default.rb
hello 'chef_user'

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🔹 ChefSpec (Unit Testing)

# spec/unit/recipes/default_spec.rb
require 'chefspec'

describe 'my_cookbook::default' do
  let(:chef_run) { ChefSpec::SoloRunner.new.converge(described_recipe) }

  it 'installs nginx' do
    expect(chef_run).to install_package('nginx')
  end
end

Run tests:

rspec

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🔹 Test Kitchen (Integration Testing)

# .kitchen.yml
driver:
  name: vagrant

provisioner:
  name: chef_zero

platforms:
  - name: ubuntu-20.04

suites:
  - name: default
    run_list:
      - recipe[my_cookbook::default]

kitchen converge
kitchen verify

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🔹 Policyfiles

Alternative to Berkshelf and runlists.

chef generate policyfile my_policy

# Policyfile.rb
name 'my_policy'
run_list 'my_cookbook::default'
default_source :supermarket
cookbook 'my_cookbook', path: '.'

chef install
chef push my_org my_policy.lock.json

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🔹 Chef Automate

Chef Automate provides UI and compliance, visibility, and workflow capabilities.

• Setup dashboards
• Integrate with InSpec for audits
• Workflow pipelines for cookbook CI/CD

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🔹 Knife Tips

knife bootstrap IP_ADDRESS -x user -P password --node-name NODE_NAME
knife node list
knife cookbook upload my_cookbook
knife role from file webserver.json

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📌 Best Practices

• Keep cookbooks modular and reusable.
• Use Berkshelf or Policyfiles to manage dependencies.
• Write tests (ChefSpec/Test Kitchen) for stability.
• Avoid hardcoding; use attributes or data bags.
• Prefer custom resources over LWRPs.