OpenStack OpenStack Orchestration (Heat) 3

Question 1

What is the role of the 'heat-api-cfn' service in OpenStack Heat?

Accepted Answer

Provides an AWS CloudFormation-compatible API endpoint for Heat

Answer

heat-api-cfn exposes a CloudFormation-compatible REST API so that AWS CloudFormation tools and templates can be used against an OpenStack Heat deployment.

Question 2

What does the 'str_replace' intrinsic function do in a Heat template?

Accepted Answer

Substitutes a substring within a string value using a template

Answer

'str_replace' is an intrinsic function that performs string substitution within a template, replacing specified placeholders with dynamic values.

Question 3

Which resource type is used in Heat to configure software on an instance after it launches?

Accepted Answer

OS::Heat::SoftwareConfig

Answer

OS::Heat::SoftwareConfig stores a software configuration script that can be applied to an instance via OS::Heat::SoftwareDeployment.

Question 4

How does Heat handle a stack update when a resource property change requires replacement?

Accepted Answer

It creates a new replacement resource before deleting the old one (by default), ensuring continuity

Answer

By default, Heat uses an 'update_replace_policy' of CREATE_BEFORE_DELETE, creating the new resource first to minimize downtime before removing the old one.

Question 5

What is a 'nested stack' in OpenStack Heat?

Accepted Answer

A stack defined by a template that is referenced as a resource within another template

Answer

A nested stack is created when a Heat template references another template as a resource (OS::Heat::Stack), enabling modular and reusable template composition.

OpenStack Practice Test

OpenStack Practice Test

OpenStack OpenStack Orchestration (Heat) 3