Basic metrics in CloudWatch for AWS services
CloudWatch automatically monitors a basic set of metrics at 5-minute intervals for free. Most AWS services send metrics automatically for free to CloudWatch metrics. These include foundational services such as EC2, S3, EBS, Kinesis, Lambda, and many others.
Basic monitoring for the EC2 service
When an instance is created, seven metrics are pushed out to CloudWatch at a frequency of every 5 minutes. You can change this frequency to 1-minute intervals for an additional charge. CloudWatch also makes a binary status check available as part of their Free Tier. Using this check is an essential measurement to see if your instance is up and running. It is not a good check to ensure that your application is performing correctly. The status check can be a canary in the coalmine for things such as AMI issues, accidentally (or purposefully) terminating an instance, or even Availability Zone or regional failures.
Besides the status check...
