• Provisioning - Server is ready with OS, Software and Networking

• Deployment - Adding or upgrading software on server

• Orchestration - Coordinated operations on multiple systems.
  When there is multiple server the coordination between them is orchestration.

• Configuration - Managing server config via files such as ram, space, dependencies etc.

• Imperative procedural - Commands to produce desired state.

• Declarative procedural - Desired state is defined and tools will achieve it.

Let's say a software need 'x' amount of resources with 'y' port open to run.To achieve this we have two approach Imperative and Declarative. In the imperative approach we write instructions and the (cloud) API is called to achieve our requirements. Where as in declarative approach, we say i need this certain infrastructure,now how you can achieve it not my concern (you may run a code endlessly or hit APIs) Eg:- Terraform tool

• Idempotent - Repeat execution and same result
  When we executing it no matter how many times,will get same result
  
  

• Blue Green Deployment - Identical deployment ,used as switch.

Almost 100% uptime is achieved

Two server all of the traffic pointed to S1 what happens is when there is new updates pointed to S2 one called blue one called green, so people are visiting on S1 therefore update is pushed on S2, after verifying all the things are working the point shifts S1 to S2 and S2 became the main server.And then new update we can push to S2

• Continuous Integration CI - Build and unit test at every checking.
  No matter what code you have written check it's integrity/integration with the existing software in your machine) it does't mean jenkins,puppet it does not means anything else.
  
  

• Continuous Delivery - Deploy on production live environment at every checking.
  Supports continuous delivery i.e in the small batches shipment should be released out to the users of the software,so that in case there is a bug or fix we can rollback and get it fixed_
  
  

• Continuous Deployment CD - After unit testing, deploy changes to production in small batches.
  In small batches push out your code to the end user,so that everything is going on smoothly