DevOps Classroom Series – 20/Apr/2020

Practical Explanation (contd)

• The manual steps were

Ubuntu:
sudo apt-get update
sudo apt-get install apache2 -y
sudo systemctl enable apache2
sudo systemctl start apache2
sudo apt install php libapache2-mod-php php-mysql php-cli
sudo systemctl restart apache2
sudo vi /var/www/html/info.php
<?php phpinfo(); ?>
sudo systemctl restart apache2

Centos:
sudo yum install httpd -y
sudo systemctl enable httpd
sudo systemctl start httpd
sudo yum install php php-mysql php-fpm
sudo systemctl restart httpd
sudo vi /var/www/html/info.php
<?php 
phpinfo(); 
?>
sudo systemctl restart httpd

• Pending steps to be automated

Ubuntu:
sudo vi /var/www/html/info.php
<?php phpinfo(); ?>
sudo systemctl restart apache2

Centos:
sudo vi /var/www/html/info.php
<?php phpinfo(); ?>
sudo systemctl restart httpd

• To create a file we can
  • Create a file on workstation and upload to chef nodes
    • Create files in chef cookbook
    • use a cookbook_file resource
  • Download the file from some url into chef nodes
    • use remote_file resource
  • Create a file on the chef nodes
    • use file resource
• For the current cookbook i would create a file in cookbook and upload it.
  • Execute the following commands on terminal in workstation

chef generate
chef generate file --help
chef generate file . info.php
# a new folder files will be created in the cookbook

• Now navigate to install recipe and use the cookbook_file resource

#
# Cookbook:: .
# Recipe:: install
#
# Copyright:: 2020, The Authors, All Rights Reserved.

# using the attribute defined in the attributes/default.rb file

package_name = node['apache']['package_name']


package node['apache']['package_name'] do
    action :install
    notifies :enable, 'service[apache]'
end

service 'apache' do
    service_name node['apache']['package_name']
    action :nothing
end

packages = node['apache']['php_packages']

packages.each do |package_now|
    package package_now do
        action :install
        notifies :restart, 'service[apache]'
    end
end

cookbook_file '/var/www/html/info.php' do
    source 'info.php'
    action :create
    notifies :restart, 'service[apache]'
end

• Now before uploading the cookbook to chef server, i want to review the cookbook i have written. chef has a tool called a foodcritic

cd <cookbook folder>
foodcritic .

• Now lets upload our cookbooks
• Wait for the convergance to happen or manually force convergance, then navigate to http://<ipaddress-of-node>/info.php

Practical Explanation Scenario with Tomcat Installation on Ubuntu

• Refer Here
• Try to use this on ubuntu 18 for installing tomcat-8

sudo apt-get update
sudo apt-get install tomcat8
sudo service tomcat8 restart
sudo apt-get install tomcat8-docs tomcat8-admin tomcat8-examples
sudo service tomcat8 restart

Is there a Need to write a cookbook from scratch all the time

• Many user might have written lot of cookbooks, can i reuse them
• Chef provides Chef-Supermarket, where there are cookbooks already written and ready to use, these are called as community cookbooks
• Our tasks:
  • We need to learn how to use community cookbooks
  • We also need to learn how to write wrapper cookbooks