You use Amazon CloudWatch as your primary monitoring system for your web application. After a recent software deployment, your users are getting Intermittent 500 Internal Server Errors when using the web application. You want to create a CloudWatch alarm and notify an on-call engineer when these occur. How can you accomplish this using AWS services? Choose three answers from the options given below.

Answer options:

A.Deploy your web application as an AWS Elastic Beanstalk application. Use the default Elastic Beanstalk Cloudwatch metrics to capture 500 Internal Server Errors. Set a CloudWatch alarm on that metric.
B.Install a CloudWatch Logs Agent on your servers to stream web application logs to CloudWatch.
C.Use Amazon Simple Email Service to notify an on-call engineer when a CloudWatch alarm is triggered.
D.Create a CloudWatch Logs group and define metric filters that capture 500 Internal Server Errors.Set a CloudWatch alarm on that metric.
E.Use Amazon Simple Notification Service to notify an on-call engineer when a CloudWatch alarm is triggered.

Answer – B, D and E
You can use CloudWatch Logs to monitor applications and systems using log data.
CloudWatch Logs uses your log data for monitoring; so, no code changes are required. For example, you can monitor application logs for specific literal terms (such as "NullReferenceException") or count the number of occurrences of a literal term at a particular position in log data (such as "404" status codes in an Apache access log). When the term you are searching for is found, CloudWatch Logs reports the data to a CloudWatch metric that you specify. Log data is encrypted while in transit and while it is at rest.
For more information on Cloudwatch logs, please refer to the below link:
http://docs.aws.amazon.com/AmazonCloudWatch/latest/logs/WhatIsCloudWatchLogs.html
Amazon CloudWatch uses Amazon SNS to send email. First, create and subscribe to an SNS topic. When you create a CloudWatch alarm, you can add this SNS topic to send an email notification when the alarm changes state.
For more information on SNS and Cloudwatch logs, please refer to the below link:
http://docs.aws.amazon.com/AmazonCloudWatch/latest/monitoring/US_SetupSNS.html