CloudWatch

AWS monitoring streams as a service

3 Major Services

Metrics

• Used to monitor most AWS services

• You monitor your environment by configuring and viewing CloudWatch metrics

• Metrics are specific to each AWS service or resource, and include such metrics as:

  • EC2 per-instance metrics:

    • CPUUtilization

    • CPUCreditUsage

  • ELB metrics:

    • RequestCount

    • UnhealthyHostCount

  • S3 metrics:

    • NumberOfObjects

    • BucketSizeBytes

• EC2 Standard level monitoring: 5 minute periods (DEV)

• EC2 Detailed monitoring: 1 minute periods (PROD) at extra charge

• Cloudwatch Alarms can be created to trigger alerts (or other actions in your AWS accounts, such as an SNS topic) based on threshold you set on CloudWatch metrics

• Auto Scaling heavily utilizes CloudWatch - relying on threshold and alarms to trigger the addition (or removal) of instances from an auto-scaling group.

Logs

• Centralized Repository

• Log Streams (e.g. EC2 CloudWatch Logs Agent)

  • Push streams of logs folders into a central repo to monitor, like Apache Server logs!!!

• Metrics can be made from Log Streams

Events

• Create rules to respond to events in Events Stream

  • Trigger Lambda function when EC2 instance enters running state

• Schedule Events

• Make simple timers or date-based events

EC2 Monitoring

• System Status Checks: (Outside of our control)

  • Loss of network connectivity

  • Loss of system power

  • Software issues on the physical host

  • Hardware issues on the physical host

  • How to solve: Generally stopping and restarting the instance will fix the issue. This causes the instance to launch on a different physical hardware device.

• Instance Status Checks: (software issues in our control)

  • Failed system status checks

  • Misconfigured networking or startup configuration

  • Exhausted memory

  • Corrupted file system

  • Incompatible kernel

  • How to solve: Generally a reboot, or solving the file system config issue

• By default, CloudWatch will automatically monitor metrics that can be viewed at the host level (not the software level), such as:

  • CPUUtilization

  • Network in/out

  • CPUCreditBalance

  • CPUCreditUsage

• OS level metrics that required a third party script (perl) to be installed (provided by AWS)

  • Memory utilization, memory used, and memory available

  • Disk Swap utilization

  • Disk space utilization, disk space used, disk space available.

CloudWatch Alarms

• Allow for you (or the sysadmin) to be notified when certain defined thresholds are met on CloudWatch Metrics

• For example, you can setup an alarm to be triggered whenever the CPUUtilization metric on an EC2 instance goes above 70%

• Alarms can also be used to trigger other events in AWS like publishing to an SNS topic or triggering auto scaling.