COA OpenStack Heat & Orchestration 3

Question 1

What is the purpose of the 'OS::Heat::AutoScalingGroup' resource?

Accepted Answer

To create a group of identical resources that can scale in or out

Answer

To automatically resize Cinder volumes based on usage

Answer

To balance load across multiple Heat stacks

Answer

To auto-recover failed instances using Ceilometer alarms

Question 2

What does 'stack rollback' do in OpenStack Heat?

Accepted Answer

Automatically deletes a stack if its creation fails, restoring the prior state

Answer

Reverts the stack to a previous template version stored in Swift

Answer

Pauses stack creation and waits for administrator approval

Answer

Rolls back only the most recently added resource in the stack

Question 3

Which command updates an existing Heat stack with a modified template?

Accepted Answer

openstack stack update

Answer

openstack stack replace

Answer

openstack stack redeploy

Answer

openstack stack patch

Question 4

What is the 'OS::Heat::WaitCondition' resource used for in Heat templates?

Accepted Answer

To block stack completion until an application inside an instance signals readiness

Answer

To pause stack creation until a time-based schedule is met

Answer

To wait for Ceilometer alarms to clear before proceeding

Answer

To enforce rate limits on Heat API requests

Question 5

Which HOT intrinsic function is used to substitute strings within a template, such as inserting a parameter value into a script?

Accepted Answer

str_replace

Answer

get_param

Answer

concat

Answer

list_join

Question 6

What does the 'openstack stack show' command display for a given stack?

Accepted Answer

Detailed information including status, creation time, parameters, and outputs

Answer

Only the resource types defined in the stack template

Answer

A graphical dependency diagram of the stack resources

Answer

The raw HOT template used to create the stack

Question 7

What Heat feature allows operators to define rules that prevent specific stack update operations, such as replacing or deleting critical resources?

Accepted Answer

Stack policies

Answer

Stack constraints

Answer

Resource guards

Answer

Update locks