---
tags:
  - puppet
references:
  - https://www.puppet.com/docs/puppet/7/lang_classes#lang_class_declare
---
Prefer include over resource-like; more flexible and idempotent. Resource-like to pass args without needing to use hieradata.

> Mixing declaration types for the same class can lead to compilation errors.

# Include-like <- preferred
Relies on external data, e.g hieradata, and defaults.
Idempotent: it is only added to the catalog once.

### `include`
Accepts: single class, class reference (`Class[..]`), comma-seperated list of those or an array of them.

## `require`
Same as above - but the class becomes a dependency of the container. #clarify dependency.

## `contain`
Adheres to same rules as above. Relationships of the containing class extend to the contained class.
See [[Containment]].

# Resource-like
Can be declared only once. 
Must be unique to avoid conflicting parameter values.