How should the SysOps administrator resolve this error?
Run cfn-signal at the completion of the user data script.
Modify the EC2 instances’ security group to allow outgoing traffic on port 443.
Reduce the Auto Scaling group’s DesiredCapacity value in the CloudFormation template.
Set the AssociatePublicIpAddress property to True in the Auto Scaling group launch template.
Explanations:
Thecfn-signalcommand is necessary for the CloudFormation wait condition to receive signals from the EC2 instances. This command should be run at the completion of the user data script to indicate successful initialization. If the signal is not sent, the wait condition will time out, causing the Auto Scaling group creation to fail.
Modifying the EC2 instances’ security group to allow outgoing traffic on port 443 may not resolve the issue, as the problem lies with the signaling to the CloudFormation stack rather than connectivity to the internet. Even with outgoing traffic allowed, ifcfn-signalis not executed, the wait condition will still not receive the required signals.
Reducing the DesiredCapacity value will not fix the signaling issue. The DesiredCapacity affects how many instances are launched but does not address the failure of the wait condition to receive signals from the instances. The issue is related to communication and not the number of instances.
Setting the AssociatePublicIpAddress property to True in the launch template would only ensure that the instances receive public IP addresses. While this can aid in connectivity, it does not resolve the core issue of the wait condition not receiving the required signals. The key is to runcfn-signal, which is not related to IP addressing.
I surmise that the answer is:
Run cfn-signal at the completion of the user data script.