What are the two main methods of describing infrastructure using Infrastructure as Code (IaC)?

Declarative and imperative.

• Declarative (Declarative IaC): Describes the desired end state of the infrastructure. The IaC tool itself determines the steps to achieve this state. Focus on "what", not on "how".

  Examples of tools: Terraform, AWS CloudFormation, Pulumi.

• Imperative (Imperative IaC): Describes the sequence of commands or steps needed to configure the infrastructure. Focus on "how", not on "what".

  Examples of tools: Chef, Puppet (classic approach), Ansible (with declarative elements).

Characteristic	Declarative approach	Imperative approach
Description	Desired end state	Sequence of steps (script)
User	Describes "what"	Describes "how"
Idempotency	Built into the tool	Achieved manually or with plugins
Conciseness	Often more concise and readable	Can be more verbose
Flexibility	Less flexible for complex logic	More flexible for non-standard scenarios
Examples	Terraform, CloudFormation, Pulumi	Chef, Puppet, OpsCode, Ansible