Health checks with Route 53 in AWS - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is the purpose of a health check in Route 53?

A health check monitors the health and availability of your resources, like web servers, to ensure traffic is only routed to healthy endpoints.

beginner

Which protocols can Route 53 health checks use to verify endpoint health?

Route 53 health checks can use HTTP, HTTPS, and TCP protocols to check if an endpoint is reachable and responding correctly.

intermediate

How does Route 53 respond when a health check fails?

When a health check fails, Route 53 stops routing traffic to the unhealthy endpoint and can route traffic to healthy alternatives if configured.

intermediate

What is the difference between a health check and a DNS failover in Route 53?

A health check monitors endpoint health, while DNS failover uses health check results to redirect traffic from unhealthy endpoints to healthy ones automatically.

beginner

Can Route 53 health checks monitor endpoints outside AWS?

Yes, Route 53 health checks can monitor any publicly accessible endpoint, including those outside AWS, as long as they respond to the health check protocol.

What happens if a Route 53 health check detects an unhealthy endpoint?

A Route 53 ignores the health check and continues routing traffic.

B Route 53 shuts down the unhealthy endpoint automatically.

C Traffic is routed away from the unhealthy endpoint to healthy ones if configured.

D The endpoint is deleted from DNS records.

Route 53 uses health check results to route traffic away from unhealthy endpoints to healthy alternatives if DNS failover is set up.

Which protocol is NOT supported by Route 53 health checks?

A FTP

B HTTPS

C TCP

D HTTP

Route 53 health checks support HTTP, HTTPS, and TCP protocols, but not FTP.

Can Route 53 health checks monitor endpoints outside of AWS?

A Only endpoints with AWS IAM roles can be monitored.

B No, only AWS resources can be monitored.

C Only endpoints in the same region can be monitored.

D Yes, any publicly accessible endpoint can be monitored.

Route 53 health checks can monitor any publicly accessible endpoint, including those outside AWS.

What is required to enable DNS failover using Route 53 health checks?

A Associate a health check with a DNS record and configure failover routing policy.

B Enable CloudWatch alarms on the endpoint.

C Create an IAM role for Route 53.

D Use a private hosted zone.

DNS failover requires associating a health check with a DNS record and setting the routing policy to failover.

How often does Route 53 perform health checks by default?

A Every 5 minutes

B Every 30 seconds

C Every 1 minute

D Every 10 seconds

By default, Route 53 performs health checks every 30 seconds to monitor endpoint health.

Explain how Route 53 health checks help improve application availability.

Think about how traffic is managed when a server is down.

Describe the steps to set up a health check and DNS failover in Route 53.

Consider the order of creating and linking components.

Practice

1. What is the main purpose of a health check in AWS Route 53?

easy

A. To monitor if a website or server is working properly

B. To increase the storage capacity of a server

C. To speed up the DNS resolution process

D. To encrypt data between users and servers

Solution

1. Step 1: Understand the role of health checks

   Health checks in Route 53 monitor the status of your website or server to see if it is working correctly.

2. Step 2: Identify the main purpose

   The main goal is to ensure traffic is sent only to healthy endpoints by checking their health status.

3. Final Answer:

   To monitor if a website or server is working properly -> Option A

4. Quick Check:

   Health check purpose = Monitor server health [OK]

Hint: Health checks watch if your site/server is up [OK]

Common Mistakes:

• Confusing health checks with encryption
• Thinking health checks speed up DNS
• Assuming health checks add storage

2. Which of the following is the correct way to configure a Route 53 health check to check an HTTP endpoint on port 80?

easy

A. Set Protocol to FTP and Port to 21

B. Set Protocol to HTTPS and Port to 443

C. Set Protocol to TCP and Port to 22

D. Set Protocol to HTTP and Port to 80

Solution

1. Step 1: Identify the protocol and port for HTTP

   HTTP uses protocol HTTP and port 80 by default.

2. Step 2: Match the correct configuration

   Setting Protocol to HTTP and Port to 80 correctly configures the health check for an HTTP endpoint.

3. Final Answer:

   Set Protocol to HTTP and Port to 80 -> Option D

4. Quick Check:

   HTTP = Protocol HTTP + Port 80 [OK]

Hint: HTTP always uses port 80 [OK]

Common Mistakes:

• Using HTTPS protocol for HTTP checks
• Choosing wrong ports like 22 or 21
• Confusing TCP with HTTP protocol

3. Given a Route 53 health check configured to check an HTTP endpoint every 30 seconds with a failure threshold of 3, how long will it take before Route 53 marks the endpoint as unhealthy after it stops responding?

medium

A. 30 seconds

B. 60 seconds

C. 90 seconds

D. 120 seconds

Solution

1. Step 1: Understand failure threshold and interval

   The health check runs every 30 seconds and requires 3 consecutive failures to mark unhealthy.

2. Step 2: Calculate total time to mark unhealthy

   3 failures x 30 seconds each = 90 seconds before marking unhealthy.

3. Final Answer:

   90 seconds -> Option C

4. Quick Check:

   3 failures x 30s = 90s [OK]

Hint: Multiply interval by failure threshold [OK]

Common Mistakes:

• Using interval time only without threshold
• Adding instead of multiplying
• Confusing seconds with minutes

4. You created a Route 53 health check for an HTTPS endpoint on port 443, but Route 53 always marks it unhealthy even though the site is up. What is the most likely cause?

medium

A. The health check is set to HTTP instead of HTTPS

B. The failure threshold is set too high

C. The endpoint is using port 80 instead of 443

D. The health check is configured with TCP protocol

Solution

1. Step 1: Check protocol mismatch

   If the health check is set to HTTP but the endpoint requires HTTPS, the check will fail.

2. Step 2: Confirm correct protocol and port

   HTTPS requires protocol HTTPS and port 443; using HTTP protocol causes failure.

3. Final Answer:

   The health check is set to HTTP instead of HTTPS -> Option A

4. Quick Check:

   Protocol mismatch causes failure [OK]

Hint: Match protocol exactly with endpoint [OK]

Common Mistakes:

• Ignoring protocol and port mismatch
• Assuming failure threshold causes failure
• Confusing TCP with HTTPS protocol

5. You want Route 53 to route traffic only to healthy web servers in multiple regions. You have health checks set up for each server. Which routing policy should you use to ensure traffic goes only to healthy servers and balances load across them?

hard

A. Simple routing policy

B. Weighted routing policy with health checks enabled

C. Latency routing policy without health checks

D. Failover routing policy

Solution

1. Step 1: Understand routing policies

   Simple routing sends traffic to one resource; failover sends to primary then backup; weighted distributes traffic by weights; latency routes to lowest latency.

2. Step 2: Choose policy that balances load and respects health

   Weighted routing with health checks enabled sends traffic only to healthy servers and balances load based on weights.

3. Final Answer:

   Weighted routing policy with health checks enabled -> Option B

4. Quick Check:

   Weighted + health checks = balanced healthy routing [OK]

Hint: Use weighted routing with health checks for balanced healthy traffic [OK]

Common Mistakes:

• Using simple routing which ignores health checks
• Failover only switches on failure, no load balance
• Latency routing without health checks risks unhealthy targets