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CloudWatch

Amazon CloudWatch is a monitoring service to monitor your AWS resources, as well as the applications that you run on AWS.

CloudWatch monitors things like:

  • Compute
    • Autoscaling Groups
    • ELBs
    • Route53 Health Checks
  • Storage and Content Delivery
    • EBS Volumes
    • Storage Gateways
    • CloudFront
  • Databases and Analytics
    • DynamoDB
    • Elasticache Nodes
    • RDS Instances
    • Elastic MapReduce Job Flows
    • Redshift
  • Other
    • SNS Topics
    • SQS Queues
    • Opsworks
    • CloudWatch Logs
    • Estimated Charges on your AWS Bill

CloudWatch and EC2

Host Level Metrics Consist of:

  1. CPU
  2. Network
  3. Disk
  4. Status Check

Exam Tip: RAM Utilization is a custom metric! By default, EC2 monitoring is 5 minute intervals, unless you enable detailed monitoring, which will then make it 1 minute intervals.

Basically, anything that's not in the 4 items listed above is a custom metric.

How Long are CloudWatch Metrics Stored

You can retrieve data using the GetMetricStatistics API or by using third party tools offered by AWS partners.

You can store your log data in CloudWatch Logs for as long as you want. By default, CloudWatch Logs will store your log data indefinitely. You can change the retention for each Log Group at any time.

Note: You can retrieve data from any terminated EC2 or ELB instance after its termination

Metric Granularity

It depends on the AWS service. Many default metrics for many default services are 1 minute, but it can be 3 or 5 minutes depending on the service.

Exam Tip: For custom metrics, the minimum granularity that you can have is 1 minute.

CloudWatch Alarms

You can create an alarm to monitor any Amazon CloudWatch metric in your account. This can include EC2 CPU Utilization, ELB Latency or even the charges on your AWS bill. You can set the appropriate thresholds in which to trigger the alarms and also set what actions should be take if an alarm state is reached. This will be covered in a subsequent lecture.

CloudWatch Exam Tips

  • Amazon CloudWatch is a monitoring service to monitor your AWS resources, as well as the applications that you run on AWS.
  • Host Level Metrics Consist of:
    • CPU
    • Network
    • Disk
    • Status Check
  • RAM Utilization is a custom metric
  • Custom Metrics: Minimum granularity is 1 minute
  • Terminated Instances: You can retrieve data from any terminated EC2 or ELB instance after its termination. CloudWatch Logs by default are stored indefinitely.
  • Metric Granularity
    • 1 minute for detailed monitoring
    • 5 minutes for standard monitoring
  • CloudWatch can be used on presmise: Not restricted to just AWS resources. Can be on premise too. Just need to download and install the SSM agent and CloudWatch agent.