SOA-C02 Deployment, Provisioning, and Automation Practice Question

Answer analysis

Option-by-option breakdown

For each option: why learners choose it and why it is or isn't the right answer here.

• ✓

  Add a CreationPolicy with a resource signal to the EC2 instance resource and have the user data script send a success signal using cfn-signal.

  Why this is correct

  A CreationPolicy on the EC2 instance resource makes CloudFormation hold the stack creation in the CREATE_IN_PROGRESS state until it receives the specified number of success signals. The user data script must invoke cfn-signal after completing its configuration steps, which directly ties the instance's readiness to the stack creation workflow. This is the only option that explicitly synchronizes CloudFormation with the completion of the user data script during initial stack creation.

• ✗

  Add a DependsOn attribute to the EC2 instance resource to wait for another resource.

  Why it's wrong here

  The DependsOn attribute only affects the order in which CloudFormation creates resources; it does not pause creation to wait for any activity inside a resource such as user data execution. Since the EC2 instance in this scenario has no other resource that must be created before it, adding DependsOn to the instance would either have no effect or, if pointed at a resource that completes later, would merely order creation without guaranteeing the user data script has finished. Therefore, it cannot ensure that the configuration tasks in user data are complete before the stack is marked as successfully created.

• ✗

  Add an UpdatePolicy with a resource signal to the EC2 instance resource.

  Why it's wrong here

  An UpdatePolicy with a resource signal is designed to control behavior during stack updates, such as specifying how many instances must report healthy before a rolling update continues. It has no effect during the initial creation of the stack, and CloudFormation will not wait for any signal from the user data script at creation time if only an UpdatePolicy is present. Thus, this approach fails to address the requirement to wait for user data completion when the stack is first being created.

• ✗

  Add a WaitCondition resource and a WaitHandle, and have the user data script send a signal to the WaitHandle.

  Why it's wrong here

  A WaitCondition and WaitHandle pair can be used to make CloudFormation wait for an external signal, but it requires the user data script to call the SignalResource API or use cfn-signal with the WaitHandle URL, not the simpler cfn-signal success call used with a CreationPolicy. While this could technically work, it adds unnecessary complexity and is not the native or recommended mechanism for an EC2 instance's user data to signal readiness. The CreationPolicy with cfn-signal is the idiomatic, straightforward way to achieve the same result during stack creation.

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