DevOps Classroom Series – 07/Apr/2020

Configuration Management

• To Understand configuration management lets take an example of a growing application like practo.
• Initially when they start, less resources (hardware) might be enough
• As the users increase we might need more servers to handle the load, so doing the configuration/installation on multiple servers becomes manadatory
• Along with this user increase or traffic increase new features are added to the application and we need to deploy them to servers.
• To handle these kind of variables we need a disciple(or process) that ensures all the software and hardware assets of the application are tracked and any future changes of the assets are also tracked.

How to do Configuration Management (CM)

• Procedural:
  • We need to describe CM steps in how it has to done
  • Examples: Shell, Powershell Scripting
  • Scenario: Creating a file and adding some content to it

  touch file.txt
  echo "some content" >> file.txt
  

• Declarative:
  • We need to describe CM Steps in what has to be done
  • Examples: Ansible, Chef
  • Scripts are written to maintain state
  • Scenario: Creating a file and adding some content to it

  Ensure a file called as file.txt is present with "some content" 
  

Configuration Management Architecture

• There are two kinds of Servers

  • Configuration Management Servers:
    • They are responsible for ensuring the configuration on nodes
    • Change history is maintained over here
  • Nodes:
    • These are the servers where the configurations/deployments/installations have to be done

• In CM We have two popular architectures

  • PULL:
    • Nodes will communicate with CM Server to understand what has to be executed
    • In this mode nodes will have an agent installed and this agent is responisble for communication with CM Server.
  • PUSH
    • CM Server will communicate with Node to inform what has to be execute
    • CM Server will login into the node and execute configuration, so credentials have to be maintained

Work to be done

• Create an Hosted Chef Account over here
• Create an AWS/Azure Account Account Refer Video Content section