EnableAlarm creates an alarm that reboots an EC2 instance whenever the CPU utilization is greater than 70% Inputs: sess is the current session, which provides configuration for the SDK's service clients instanceName is the name of the EC2 instance instanceID is the ID of the EC2 instance alarmName is the name of the alarm Output: If successful, nil Otherwise, the error from a call to PutMetricAlarm or EnableAlarmActions.