External Monitoring#

With an EC2 instance running, we get some monitoring data automatically and at no extra charge.

There are certain things that a running instance must communicate to the hardware/system that hosts it. AWS needs to track this information “from the outside” in order to manage its infrastructure. For example:

  • How much CPU is the instance using?
  • How much network bandwidth is it taking up?
  • How much data is it reading from and/or writing to disk?

All these things can be monitored externally by AWS, and they package it into a service called CloudWatch Metrics. The metrics allow us to answer questions like:

  • Is my server doing anything? (If not, you’ll see idle CPU usage.)
  • Is my server overloaded? (Watch for sustained high CPU usage.)
  • Is my server consuming too much bandwidth? (Watch network usage.)

These are a great start, and for some services they’re all you need.

Assignment#

Cost check: Basic CloudWatch metrics for EC2 (CPU, network, disk) are included at no extra charge. CloudWatch dashboards have a small monthly cost, so delete your test dashboard when you clean up resources.

Create a dashboard for patientping-web-v2, force CPU usage high, verify the spike, then stop the load.

  1. In the AWS Console, go to “CloudWatch” → “Dashboards” and click “Create dashboard.”
  2. Name the dashboard patientping-dashboard and click “Create dashboard.”
  3. Add a line widget for patientping-web-v2 CPU:
    1. Choose “Line” when prompted for widget type.
    2. In metric namespaces, select “EC2” → “Per-Instance Metrics.”
    3. Search for your instance ID, and select the row where the metric is CPUUtilization, then check it.
    4. Click “Create widget.”
    5. Set the dashboard timeframe to “15 minutes”.
    6. Click “Save dashboard.”
  4. SSH into patientping-web-v2 and start CPU load:
yes > /dev/null
  1. Keep the load running for at least 5 minutes so the dashboard shows a clear CPU spike!
  2. Once you’re satisfied that your monitoring is working, stop the load by pressing Ctrl+C in the terminal where you ran the yes command.
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