Fixing Capacity Error in Placement Group
Question
You currently have 9 EC2 instances running in a Placement Group.
All these 9 instances were initially launched at the same time and seem to be performing as expected.
You decide that you need to add 2 new instances to the group; however, when you attempt to do this you receive a 'capacity error'
Which of the following actions will most likely fix this problem? Choose the correct answer from the options below.
Answers
Explanations
Click on the arrows to vote for the correct answer
A. B. C. D.Answer - B.
AWS recommends to try and launch the instances again.
For more information on this error , just browse to the below URL:
http://docs.aws.amazon.com/AWSEC2/latest/UserGuide/instance-capacity.htmlThe correct answer is: C. Request a capacity increase from AWS as you are initially limited to 10 instances per Placement Group.
Explanation:
A Placement Group is a logical grouping of instances within a single Availability Zone (AZ) that enables applications to participate in a low-latency, 10 Gbps network. When instances are launched in a Placement Group, they are placed in close physical proximity to each other, which can significantly reduce network latency and improve network throughput.
By default, you are limited to launching up to 10 instances per Placement Group, and it's not possible to add more instances to the group once it has been created.
In the given scenario, since there are already 9 instances running in the Placement Group, attempting to launch two more instances will result in a capacity error. This error indicates that the Placement Group has already reached its capacity limit of 10 instances.
Therefore, the most appropriate solution in this case is to request a capacity increase from AWS. This can be done by submitting a support ticket through the AWS Management Console or by contacting AWS Support directly.
Option A, creating a new Placement Group and launching the new instances in the new group, is not a viable solution since instances in different Placement Groups cannot communicate with each other using low-latency networking.
Option B, stopping and restarting the instances in the Placement Group and then trying the launch again, is also not a viable solution since it does not address the underlying capacity limit issue.
Option D, making sure all the instances are the same size and then trying the launch again, is not relevant to the capacity limit issue and would not solve the problem.
