CloudWatch

What is it

• https://aws.amazon.com/cloudwatch/

• monitoring service to monitor health and performance metrics of you applications and AWS resources

  • by default can monitor compute, storage & content delivery, database & analytics, and a variety of other AWS services
  • can even monitor estimated AWS charges

• CloudWatch Agent - allows you to define your own metrics to monitor

• OperatingSystem-Level metrics

  • by default OS-level metrics are not sent to CloudWatch - need to use the CloudWatch agent to do this

    • memory usage, processess, CPU idle time, etc

  • metric frequency - by default sent in 5-min intervals

    • can enable detailed monitoring for 1-min intervals for an extra charge
    • custom metrics default to 1-min intervals but high resolution metrics can be configured for 1-sec intervals (extra charge)

• host-level metrics

  • default EC2 metrics include CPU, network, disk, status check

• CloudWatch Logs - allows you to monitor OS and application logs

  • system and application logs - useful to track errors and troubleshoot

• CloudWatch Alarms

  • alarms you can create to monitor any CloudWatch metric

    • cpu or memory ulitization, latency, AWS bill charges, etc.
    • can set thresholds on the metric to trigger the alarm

  • alarms can trigger things e.g. executing an Auto Scaling policy

CloudWatch Metric

• a variable you want to monitor using CloudWatch

• time-ordered sequence of data-points that are published to Cloudwatch

  • each data-point has a timestamp and optional unit of measurment

• for example, logging the CPU usage on an instance

• uniquely defined by a name, namespace, and zero or more dimensions

CloudWatch Namespaces

• a container for CloudWatch metrics

• AWS provides its own (e.g. AWS/EC2 for EC2 metrics) and you can create your own for custom metrics data

  • each data-point you want to publish to CloudWatch must have a specified namespace
  • each metric you create must have a specifiec namespace

• metrics in different namespaces are isolated from one another - they are not aggregated together

CloudWatch Dimensions

• similar to a filter
• name-value pair used to filter CloudWatch data
• CloudWatch can aggregate data across dimensions for some service (like EC2)

CloudWatch Dashboards

• custom dashboard views you can create in CloudWatch to visualize/display specified metrics

CloudWatch Actions

• CloudWatch API supports a long list of actions, https://docs.aws.amazon.com/AmazonCloudWatch/latest/APIReference/API_Operations.html

  • actions allow you to publish, monitor, and alert on metrics

• very useful when creating custom metrics

• PutMetricData (super common action)

  • publishes metric data-points to CloudWatch
  • define the name of the metric, the namespace to publish it to, the value to publish, and timestamp for the data-point

• PutMetricAlarm (super common action)

  • creates an alarm associated with a metric to alert you if a threshold has been reached

CloudTrail

What is it

• https://aws.amazon.com/cloudtrail/

• records API calls (user activity) in your AWS account - events related to creation, modification, or deletion of resources (also includes failed logins)

  • stores log files in an S3 bucket

• by default shows the last 90 days of activity

• can be integrated with CloudWatch Logs

• used for audit logs, not performance and metrics