DevOps Classroom Series – 28/May/2021

Installing apache server on ubuntu

• Launch a ubuntu VM
• Login into the VM and execute the following commands

sudo apt update
sudo apt install apache2 -y

• Verify the installation by navigating to public IP
• Verify the installation from command line

Lets do this in Chef

• Now lets try to create a cookbook in chef which automates the above activity

• We need a cookbook:

  • Navigate to chef-repo\cookbooks folder
  • Lets create a chef cookbook Refer Here
  • I will be creating a cookbook for installing apache using the following

  chef generate cookbook myapache -b --chef-license accept
  

  

• A new directory will be created. will have some files and folders

• Chef is developed using ruby language. Chef has its own DSL (Domain Specific Language). If required we can directly use ruby in chef cookbooks.

• Launch the cookbook in visual studio code, install chef extension

• Now execute the command berks install

• In Chef cookbook there is already a recipe created called as default (recipes\default.rb)

• In chef recipe we will be using resources to automate the manual steps

• The resources in chef will have following syntax

<resource type> 'name' do 
   property1 value1
   ...
   propertyn valuen
   action <action to acheive>
end

• In recipes\default.rb

apt_update 'ubuntu packages' do
  action :update
end

# sudo apt install apache2 -y
apt_package 'apache2' do
    action :install
end

• Now upload the recipe to the chef server

berks upload

• Once the cookbook is uploaded, we need to specify to chef server on which nodes should the recipes be executed.

• Now we need to change the nodes run_list

• Do this for the other ubuntu node

• Now we can wait till the nodes query the server about the work that needs to be done (Convergence)

• For lab purposes lets manually force the convergence

  • login into the node & execute sudo chef-client

• Creating and making cookbooks work is the major activity in the cookbook development

• Uploading cookbook to the server adding it to run_list etc can be done once our cookbooks are working.

• Next Steps:

  • Becoming good at writing cookbooks
  • Local development of cookbooks, testing them and upload right versions to server

Cookbook

• Cookbook is fundamental unit of configuration and distribution in chef.
• A cookbook defines a scenario and contains everything needed to support that scenario
  • Recipe
  • Attributes
  • Files
  • Templates
  • Custom Resources