DevOps Classroom Series – 11/Apr/2020

Configuration Mangement(CM) in Chef

• To do CM ensure (Are aware of manual way)
  • You are aware of all the prerequisite softwares to be installed.
  • You have a list of commands to be executed to deploy the application

Hello-World Chef Scenario

• As of now we have a Lab setup

• Now Scenario is

  • We want all of our chef-client nodes to have the following softwares installed
    • tree
    • git
    • elinks

• Commands for installing the above on

  • Ubuntu:

  sudo apt-get update
  sudo apt-get install git -y
  sudo apt-get install tree -y
  sudo apt-get install elinks -y
  

  • Centos:

  sudo yum install git -y
  sudo yum install tree -y
  sudo yum install elinks -y
  

• To develop cookbooks we will be using visual studio code

• Workflow to be followed in Chef:

  1. Generate a cookbook if required or else use the existing cookbook
  2. Generate a recipe or use the existing recipe
  3. Find a chef resource for every linux command you have noted (as above)
  4. Test whether the recipe (or the changes) are working or not
  5. upload the Cookbook to Chef Infra Server
  6. make changes if necessary to the run list of the nodes and wait for convergance

• How to realize the above workflow

  1. To generate a cookbook, when we install chefdk on workstation we get generators and we can generate using command. Navigate to chef-repo and with in chef-repo you have cookbooks folder cd into that

  cd C:\DevOps\Chef\Apr20\chef-starter\chef-repo\cookbooks
  chef generate --help
  chef generate cookbook --help
  chef generate cookbook helloworld -b
  

  

  2. To generate a recipe in the cookbook use the command chef generate recipe --help. But in this scenario, i will be using a default recipe called as default.rb already generated with cookbook ![Previewhttps://directdevops.blog/wp-content/uploads/2020/04/chef25.png)

  3. To find the resource Naviagate to here and find the resources in the highlighted section as shown below

     • Easier way to do this is understand resources syntax and then google
     • Resource syntax

     <resource type> 'name' do 
         attribute 'value'
         action :action_type
     end
     

     • Resource example:

     file 'readmeattempt' do
         path '/home/ubuntu/test/readme.txt'
         action :create
     end
     

     • Now if you want to find resource easily google ‘<linux command> in chef’ for example ‘yum in chef’

  4. My default.rb looks as shown below

  #
  # Cookbook:: helloworld
  # Recipe:: default
  #
  # Copyright:: 2020, The Authors, All Rights Reserved.
  
  # install git 
  yum_package 'git' do
      package_name 'git'
      action :install
  end
  

  5. Now i will upload the cookbook to chef server

  cd helloworld
  berks install 
  berks upload
  

  6. Navigate to manage.chef.io and login
  7. Now edit run lists
  8. Now wait for convergance on the node or manually force converge sudo chef-client

Dev IDE Setup

• Open the folder with visual studio code
• Navigate to extensions
• Search for chef and install