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

Handles only internal Heat RPC calls

Answer

Manages Heat template versioning

Answer

Provides the Horizon dashboard for Heat

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

Replaces an entire resource definition

Answer

Converts a resource reference to a string

Answer

Replaces a parameter default value

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::Nova::UserData

Answer

OS::Heat::InstanceConfig

Answer

OS::Compute::SoftwareSetup

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

It immediately deletes and recreates the resource with no overlap

Answer

It refuses the update and returns an error

Answer

It only updates the metadata without touching the resource

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 stack running inside a container

Answer

A stack within a private tenant network

Answer

A stack with more than 100 resources

Question 6

Which Heat policy resource is used to trigger auto-scaling actions based on Ceilometer alarms?

Accepted Answer

OS::Heat::ScalingPolicy

Answer

OS::Nova::ScaleAction

Answer

OS::Ceilometer::ScalingTrigger

Answer

OS::Heat::AlarmAction

Question 7

What does the 'rollback_on_failure' option do when creating a Heat stack?

Accepted Answer

Automatically deletes all created resources if the stack creation fails, returning to a clean state

Answer

Reverts only the last resource change on failure

Answer

Logs the failure but keeps partial resources

Answer

Retries the stack creation three times before failing