Health checks with Route 53 in AWS - Step-by-Step Execution

Process Flow - Health checks with Route 53

Create Health Check

↓

Route 53 Monitors Endpoint

↓

Health Check Status: Healthy?

↓

Route Traffic

↓

End User Gets

↓

Normal Response

Route 53 creates a health check to monitor an endpoint. If healthy, traffic flows normally. If unhealthy, Route 53 redirects traffic or sends alerts.

Execution Sample

AWS

Create health check for example.com
Route 53 checks endpoint every 30 seconds
If endpoint responds OK, mark healthy
If fails 3 times, mark unhealthy
Route 53 routes traffic based on health

This setup monitors a website and routes traffic only if the site is healthy.

Process Table

Step	Action	Health Check Result	Route 53 Decision	Traffic Behavior
1	Route 53 sends health check request	No response yet	Waiting	Traffic normal (initial)
2	Endpoint responds OK	Healthy	Route 53 marks healthy	Traffic routed to endpoint
3	Route 53 sends health check request	Healthy	No change	Traffic routed to endpoint
4	Endpoint does not respond	Unhealthy count 1	Still healthy (threshold not met)	Traffic routed to endpoint
5	Endpoint does not respond	Unhealthy count 2	Still healthy (threshold not met)	Traffic routed to endpoint
6	Endpoint does not respond	Unhealthy count 3	Marked unhealthy	Traffic redirected or failover triggered
7	Route 53 sends health check request	Endpoint recovers	Marked healthy	Traffic routed back to endpoint

💡 Health check marks unhealthy after 3 failures and redirects traffic accordingly

Status Tracker

Variable	Start	After Step 2	After Step 5	After Step 6	After Step 7
Health Check Status	Unknown	Healthy	Healthy (unhealthy count 2)	Unhealthy	Healthy
Unhealthy Count	0	0	2	3	0
Traffic Routing	Normal	Normal	Normal	Redirected	Normal

Key Moments - 2 Insights

Why does Route 53 wait for 3 failed checks before marking unhealthy?

Route 53 uses a threshold of 3 failures to avoid false alarms from temporary glitches, as shown in steps 4-6 where unhealthy count increases before status changes.

What happens to traffic when the health check status changes to unhealthy?

At step 6, once unhealthy count reaches 3, Route 53 marks the endpoint unhealthy and redirects traffic or triggers failover, preventing users from reaching a bad endpoint.

Visual Quiz - 3 Questions

Look at the execution table, what is the health check status at step 5?

A Unknown

B Healthy

C Unhealthy

D Degraded

💡 Hint

Check the 'Health Check Result' column at step 5 in the execution table.

At which step does Route 53 redirect traffic due to health check failure?

A Step 4

B Step 5

C Step 6

D Step 7

💡 Hint

Look at the 'Traffic Behavior' column where traffic changes from normal to redirected.

If the endpoint recovers at step 7, what happens to the unhealthy count?

A It resets to 0

B It stays at 3

C It increases to 4

D It decreases to 2

💡 Hint

Refer to the 'Unhealthy Count' variable in the variable tracker after step 7.

Concept Snapshot

Route 53 health checks monitor endpoints regularly.
If endpoint fails checks 3 times, Route 53 marks it unhealthy.
Traffic is redirected or failover triggered on unhealthy.
When endpoint recovers, health status resets and traffic returns.
This ensures users reach healthy resources only.

Full Transcript

This visual execution shows how AWS Route 53 health checks work. First, Route 53 creates a health check for an endpoint. It sends requests every 30 seconds. If the endpoint responds OK, Route 53 marks it healthy and routes traffic normally. If the endpoint fails to respond three times in a row, Route 53 marks it unhealthy and redirects traffic to a backup or triggers an alert. When the endpoint recovers, Route 53 marks it healthy again and resumes normal traffic routing. This process helps keep user traffic flowing only to healthy resources, improving reliability.