Devops Classroom Series – 29/Jan/2021

Chef Supermarket

• There are lot of community cookbooks available for usage, we can use them instead of writing/developing cookbooks from scratch

• They are hosted at Chef Supermarket website Refer Here

• Scenario: Lets make use of chef supermarket cookbooks to install mysql and tomcat on ubuntu and centos machines

• Refer Here for the mysql cookbook that can be used

• Lets create a cookbook called as supermarket demo

• Lets configure kitchen.yaml to create centos and ubuntu machines

• Mention about the depencies in the metadata.rb file.

  • ~> refers to pesimistic versioning. (~> 1.0.0 => will accept 1.0.x)
  • = refers equals (=> 1.0.1 )
  • > < <= >= for less and grater than particular version numbers

• Add depends to the metadata.rb to define dependency

• Now execute berks install

• Refer Here for the changeset

• Now lets add the dependency to install tomcat server. Refer Here for supermarket docs

• Refer Here for the changeset

• Now lets try to install mongo db Refer Here

• Whenever we use supermarket cookbooks as dependencies, there are two possible ways of using dependency

  • use the custom resources developed to perform some action

    tomcat_install 'helloworld' do
        version '8.0.36'
    end
  
    tomcat_service 'helloworld' do
        action :start
    end
  

  • Include the recipe of the dependency in run_list or use include_recipe. In this case we might also define some attributes to change the behavior

  include_recipe "sc-mongodb::default"
  

• Best Practices

  • Always use the cookbooks from supermarket which have recent updates and lot of followers
  • For Production try to use equals operator in metadata.rb as the results will be consistent

• Exercise:

  • Try install postgres server using supermarket cookbooks