Model Description

Note

Document explains the Model Definition and its components.

The Model is essentially a configuration of a system. It serves two purposes:

• An assertion verification about system integrity (information only)

• A state enforcement as a configuration management system does

The Aodel is written in YAML format, and it is following a specific expression schema and logic.

This document explains each part of the Model Description.

• Layout and Setup
• Entities
• Actions
• Constraints
• Relations
• Entity States
• Event Processing
• Fact Functions
• Inheritance
• Telemetry

Model Description is written in YAML format, using declarative method. Declarative approach is considered better than imperative approach for several reasons.

Declarative Approach

It allows to define the desired end state of the system without specifying the step-by-step instructions to achieve it. With declarative configuration, one can abstract away the low-level details and apply the same configuration across many systems or environments. This allows to reuse the same Model Description, only inheriting specific parts to be changed.

Declarative configurations are usually shorter and easier to maintain because they allow to focus only on the final result, instead on the individual steps. Changes are more intuitive and involve only describing how the system should look after the change.

Imperative Approach

It requires describe the steps explicitly in order to get the system to the desired state. Imperative approach requires writing detailed code for each environment. This usually leads to a complex, difficult-to-manage configurations when scaling across many systems. Imperative instructions tend to grow more complex as more steps are added, making them very hard to debug and maintain over time.

The declarative approach is much easier to comprehend and use, because it focuses on what the system should do, rather than how to achieve it. In this way more readable and maintainable configurations are achieved. Maintenance is easier because the configurations remain simple and predictable.

Important

In a nutshell, declarative configurations are easier for teams to understand, update, and share for collaboration.