Amazon CloudWatch provides monitoring for Amazon Web Services (AWS) and the applications that make use of AWS. There are many alternatives to collecting resource utilization metrics from EC2 instances, however when AWS services like ELB, RDS, DynamoDB, SQS, etc. are used, CloudWatch metrics play a critical role in the monitoring of the applications running on AWS cloud. One of the key capabilities of CloudWatch service is the alarms. A CloudWatch alarm can watch a single metric over a specified time period and execute automated actions based on the value of the watched metric and given threshold. The automated action may be sending emails, or calling HTTP/S end points, etc.