DevOps - Chef

Chef is a configuration management and automation platform from Opscode. Chef used to automate, test and replicate infrastructure with ease.

Chef available in two format 

  1   Chef – Solo 

     a   Used to install, configure and manage the packages on single environment

  2   Chef - client and server configuration

     a   Chef – Server will be used 

     b   Chef – Client will deployed on linux/windows machine and configured with server

How to Use Chef – Client and server

Setup Chef Server

  1   Download the latest Chef server core

  2   Install the server

  3   Run the chef-server-ctl command to start the Chef server services

  4   Create a User and Organization to link your Chef server with workstations and nodes

Workstations (Client)

Chef workstation is used create and configure any recipes, cookbooks, attributes, and other changes made to Chef Configurations

  1   Download the latest Chef Development Kit for Windows/Linux 

  2   Install ChefDK (based on DK you downloaded)

  3   Generate the chef-repo 

     a   For Linux - mkdir .chef

  4   Navigate/Move to the newly-created directory (/.chef)

  5   Add the RSA Private Keys (You can download same from chef website)

     a   https://manage.chef.io/login

     b   Open the Chef management console.

     c   Click Policy.

     d   Click Clients.

     e   Click Create.

     f   Copy the private key or download and save the private key locally

 6   Generate knife.rb

 7   Create a knife configuration file by navigating to ~/chef-repo/.chef folder and create a file named knife.rb

 8   Add following details into file and save

log_level                :info

log_location             STDOUT

node_name                'username'

client_key               '~/chef-repo/.chef/username.pem'

validation_client_name   'shortname-validator'

validation_key           '~/chef-repo/.chef/shortname.pem'

chef_server_url          'https://123.45.67.89/organizations/shortname'

syntax_check_cache_path  '~/chef-repo/.chef/syntax_check_cache'

cookbook_path [ '~/chef-repo/cookbooks' ]

Node (Client)

chef-client will be run from node system. 

The chef-client checks the current configuration of the node against the recipes and policies stored in the Chef server and brings the node up to match. 

The process begins with the chef-client checking the node’s run list, loading the cookbooks required, then checking and syncing the cookbooks with the current configuration of the node.

Cookbooks

Cookbooks are the main component of configuring nodes on a Chef infrastructure. Cookbooks are comprised of recipes, metadata, attributes, resources, templates, libraries,

Recipes

Recipes are the fundamental part of cookbooks

Recipes are written in Ruby and contain information in regards to everything that needs to be run, changed, or created on a node

Attributes

Attributes define specific values about a node and its configuration