Seeing nodes are in DOWN state with Reason (Code:InsufficientInstanceCapacity)... - Amazon ParallelCluster
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Seeing nodes are in DOWN state with Reason (Code:InsufficientInstanceCapacity)...

You are experiencing an insufficient capacity issue. Follow https://aws.amazon.com/premiumsupport/knowledge-center/ec2-insufficient-capacity-errors/ to troubleshoot the issue. For more information about Amazon ParallelCluster's fast insufficient capacity fail-over mode, see Slurm cluster fast insufficient capacity fail-over.