The exam covers different domains of knowledge and the first one focuses on testing your understanding of how to monitor your environment and manage costs in your environment. This section will look at your ability to understand the CloudWatch monitoring environment and what kinds of metrics and logs it can store and display in the management console. There are several crucial aspects to remember about CloudWatch:

• By default, there's no cost associated with the metrics unless you enable detailed monitoring.
• You can deliver any kind of custom metrics to CloudWatch with detailed monitoring down to one second.
• CloudWatch doesn't have access to the EC2 operating system, meaning that any metrics or logs that can't be collected by the hypervisor require the delivery of custom metrics or the use of the CloudWatch agent to stream logs.
• Remember, you can always deliver logs either to CloudWatch or store them in S3 
• Tagging is very useful when monitoring as it can help analyze metrics from several different services in one visualization.

To test your understanding of how to understand and control costs in AWS, the exam will probe your general understanding of how billing works in AWS and what the cost structure of services in AWS is. You should be able to demonstrate a fairly high level of understanding of costs—for example, whether it is cheaper to store files on S3 or EBS. There are several crucial aspects to remember about cost management: 

• Make sure you understand which services are charged on what kind of use. Some services have charges for provisioned resources, some for requests, some for the amount or time consumed, and so on.
• CloudWatch billing alarms can help with controlling costs and projecting usage amounts.
• Consolidated billing is the right approach when you need to centralize billing for several AWS accounts.
• Read the questions carefully and look for the crucial metric that would cause one service to be more expensive than the other—be it the number of requests, the size of the data, whether the data is being sent in out of AWS, are we crossing regions, and so on.