How to Use Health Check in Route 53 for Reliable DNS Routing

In AWS Route 53, you use health checks to monitor the health of your endpoints like web servers or IP addresses. You create a health check and then associate it with DNS records so Route 53 routes traffic only to healthy endpoints.

Syntax

A Route 53 health check requires these main parts:

• IPAddress or Domain Name: The endpoint to check.
• Port: The port number to connect to (e.g., 80 for HTTP).
• Type: The protocol used (HTTP, HTTPS, TCP).
• Request Interval: How often Route 53 checks the endpoint.
• Failure Threshold: Number of failed checks before marking unhealthy.

bash

aws route53 create-health-check --caller-reference unique-string --health-check-config IpAddress=192.0.2.44,Port=80,Type=HTTP,ResourcePath="/",RequestInterval=30,FailureThreshold=3

Example

This example creates a health check for a web server at IP 192.0.2.44 on port 80 using HTTP. It checks every 30 seconds and marks unhealthy after 3 failures.

bash

aws route53 create-health-check --caller-reference "example-health-check-001" --health-check-config IpAddress=192.0.2.44,Port=80,Type=HTTP,ResourcePath="/",RequestInterval=30,FailureThreshold=3

Output

{
  "HealthCheck": {
    "Id": "abcdef12-3456-7890-abcd-ef1234567890",
    "CallerReference": "example-health-check-001",
    "HealthCheckConfig": {
      "IPAddress": "192.0.2.44",
      "Port": 80,
      "Type": "HTTP",
      "ResourcePath": "/",
      "RequestInterval": 30,
      "FailureThreshold": 3
    },
    "HealthCheckVersion": 1
  }
}

Common Pitfalls

• Not associating the health check with a DNS record, so Route 53 does not use it for routing.
• Using incorrect IP address or domain name in the health check.
• Setting too short a RequestInterval causing unnecessary load.
• Not allowing Route 53 health check IP ranges in your firewall, causing false failures.

bash

aws route53 change-resource-record-sets --hosted-zone-id Z1234567890 --change-batch '{"Changes":[{"Action":"UPSERT","ResourceRecordSet":{"Name":"example.com","Type":"A","SetIdentifier":"primary","HealthCheckId":"abcdef12-3456-7890-abcd-ef1234567890","TTL":60,"ResourceRecords":[{"Value":"192.0.2.44"}]}}]}'

Output

{
  "ChangeInfo": {
    "Id": "/change/XYZ1234567890",
    "Status": "PENDING",
    "SubmittedAt": "2024-06-01T12:00:00Z"
  }
}

Quick Reference

Parameter	Description	Example
IpAddress	The IP address to check	192.0.2.44
Port	Port number for the check	80
Type	Protocol type (HTTP, HTTPS, TCP)	HTTP
ResourcePath	Path to request for HTTP/HTTPS	/
RequestInterval	Seconds between checks	30
FailureThreshold	Failures before unhealthy	3
HealthCheckId	ID to link with DNS record	abcdef12-3456-7890-abcd-ef1234567890

Key Takeaways

Create a health check with the correct IP, port, and protocol to monitor your endpoint.

Associate the health check ID with your DNS record to enable health-based routing.

Allow Route 53 health check IP ranges in your firewall to avoid false failures.

Set reasonable check intervals and failure thresholds to balance responsiveness and load.

Use health checks to improve availability by routing traffic only to healthy endpoints.