Default free metrics are 5 min intervals. Custom metrics are 1 min intervals.
Stored for 2 weeks
Only host level metrics such as below are available free
Memory metrics are not available by default. Its a custom metric done by scripts run in EC2
You can create dashboards to customize your cloud watch metrics
Alarms can be created to monitor resources such as EC2 or ELB
Choose resource (EC2 or ELB or DynamoDB etc)
Threshold: Example: CPU utilization >= 70% for 2 out of 5 data points
Actions: Example: Send email
Events help you respond to events (state changes) in AWS resources
Example: Update DNS with public ip after EC2 starts successfully
Help you aggregate, store and monitor logs
Cloud Trail is for auditing. Totally different from CloudWatch. Cloud trail logs all changes (create user, delete user, launch EC2 delete bucket etc) to your AWS account’s resources so you can go and see what changed when by who.