CPU 100% starts at 12:20-12:30 EST

Hello aws_lover (Great name by the way :D), sorry to hear about your experience with CPU spiking to 100% at 12:20-12:30 EST.

One of the first things I would check is the crontab of your instance (assuming this is a Linux or Unix instance) to see if you have a scheduled backup or some sort of batch job running at the same time every day. I've seen this in the past when nightly data backups would run at the same time every night and consume all compute resources. See the following link for more details -> https://docs.aws.amazon.com/lambda/latest/dg/services-cloudwatchevents-expressions.html

Another option you might consider is "Scheduled Scaling" as part of Amazon EC2 Auto-Scaling. Scheduled scaling helps you to set up your own scaling schedule according to predictable load changes. In your scenario, each day between 12:20-12:30 you know that the cpu is going to spike. You can configure a schedule for Amazon EC2 Auto Scaling to increase capacity at 12PM and decrease capacity at 1PM. See the following link for more details -> https://docs.aws.amazon.com/autoscaling/ec2/userguide/ec2-auto-scaling-scheduled-scaling.html

I would also recommending looking at CloudWatch logs to see what is consuming the CPU as well as setting up a CPU usage alarm that will get triggered when CPU goes above the high water mark that you set for it. You can create an CloudWatch alarm that sends an email or SMS notification using Amazon SNS when the alarm changes state from OK to ALARM. See the following link for more details -> https://docs.aws.amazon.com/AmazonCloudWatch/latest/monitoring/US_AlarmAtThresholdEC2.html

Hopefully this helps. Thank you and good luck!