Route 53 - Health Checks¶

• HTTP Health Checks are only for public resources

• Health Check => Automated DNS Failover

  • Health checks that monitor an endpoint (application, server, other AWS resource)
  • Health checks that monitor other health checks (Calculated Health Checks)
  • Health checks that monitor CloudWatch alarms (full control) - e.g. throttles of dynamodb, alarms on RDS, custom metrics (helpful for private resources)

• Health Checks are integrated with CloudWatch metrics

Monitoring an Endpoint¶

• About 15 global health checkers will check the endpoint health
  • Health/Unhealthy threshold - 3 (default)
  • Interval - 30 seconds (can set up to 10 seconds - higher cost)
  • Supported protocols: HTTP, HTTPS, TCP
  • If > 18% of health checkers report the endpoint is healthy, route 53 considers it healthy. Otherwise, it's unhealthy.
  • Ability to choose which locations you want route 53 to use.
• Health Checks pass only when the endpoint responds with 2xx or 3xx status codes
• Health Checks can be set up to pass / fail basedon the test in the first 5120 bytes of the response
• Configure your router/firewall to allo incoming requests from route 53 health checkers

Calculated Health Checks¶

• Combine the results of multiple checks into a single health check
• You can use OR, AND or NOT
• Can monitor up to 256 Child Health Checks
• Specify how many of the health checks need to pass to make the parent class
• Usage: perform maintenance to your website without causing all health checks to fail

Health Check - Private Hosted Zones¶

• Route 53 Health checkers are outside the VPC
• They can't access private endpoints (private VPC or on-premises resources)
• You can create a CloudWatch metric and associate CloudWatch Alarm, then create a Health Check that checks the alarm itself.