You are running a multi-tier architecture on AWS with webserver instances running Nginx. Your users are getting errors when they use the web application. How can you diagnose the errors quickly and efficiently?

Answer options:

A.Install the CloudWatch Logs agent and send Nginx access log data to CloudWatch. From there, pipe the log data through to a third party logging and graphing tool.
B.Install the CloudWatch Logs agent and send Nginx access log data to CloudWatch. Then, filter the log streams for searching the relevant errors.
C.Send all the errors to AWS Lambda for processing.
D.Send all the errors to AWS Config for processing

Answer – B
The AWS Documentation mentions the following
You use metric filters to search for and match terms, phrases, or values in your log events. When a metric filter finds one of the terms, phrases, or values in your log events, you can increment the value of a CloudWatch metric. For example, you can create a metric filter to search for and count the occurrence of the word ERROR in your log events.
For more information on Cloudwatch logs Analysis,please see the below link:
http://docs.aws.amazon.com/AmazonCloudWatch/latest/logs/FilterAndPatternSyntax.html