🔔Alerting

Monitor as you will, but don't forget to set alarms to inform you of any incoming dumpster fires!

Alerts (or alarms; same thing) are usually connected to metrics. When the metric is triggered, the alert goes off. Easy peasy.

🎯 Example: We set up an alarm in serverless.yml on lines 75-83. This particular alarm gets attached to the deploymentSettings object and was (as seen previously) part of how we ensure that an alarm can cancel a canary deployment.

serverless.yml

custom:
  alerts:
    dashboards: true

functions:
  FakeUser:
    [...]
    alarms:
      - name: CanaryCheck
        namespace: 'AWS/Lambda'
        metric: Errors
        threshold: 3
        statistic: Sum
        period: 60
        evaluationPeriods: 1
        comparisonOperator: GreaterThanOrEqualToThreshold
    deploymentSettings:
      [...]
      alarms:
        - FakeUserCanaryCheckAlarm

You can extend this behavior to, for example, communicate the alert to an SNS topic which in turn can inform a pager system, Slack/Teams, or send an email to a relevant person. A better way of doing this would probably use a shared service that can also keep a stored log of all events, rather than just relaying the alert directly to a source.