Health checks with Route 53 in AWS - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ service_behavior

intermediate

How does Route 53 respond when a health check fails?

If you configure a Route 53 health check for a web server and the health check fails continuously, what will Route 53 do with DNS queries for that server's domain?

A Route 53 stops routing traffic to the unhealthy endpoint and routes to healthy alternatives if configured.

B Route 53 continues to respond with the IP address but adds a warning in the DNS response.

C Route 53 stops responding to DNS queries for the domain.

D Route 53 automatically deletes the DNS record associated with the unhealthy endpoint.

💡 Hint

Think about how DNS routing adapts to endpoint health.

Route 53 health checks monitor endpoints and when an endpoint is unhealthy, Route 53 stops routing traffic to it if failover or routing policies are configured. It does not delete records or stop DNS responses entirely.

❓ Configuration

intermediate

Which configuration enables Route 53 health checks to monitor an HTTP endpoint?

You want Route 53 to check if your web server is responding correctly on port 80 using HTTP. Which health check configuration is correct?

A Specify IP address, port 80, protocol TCP.

B Specify IP address, port 443, protocol HTTPS.

C Specify domain name, port 80, protocol HTTP, and a path like '/health'.

D Specify domain name, port 22, protocol SSH.

💡 Hint

HTTP health checks require protocol and path details.

To monitor a web server with Route 53 health checks, you specify the domain or IP, port 80, protocol HTTP, and optionally a path that returns a success status.

❓ Architecture

advanced

Designing a fault-tolerant DNS setup with Route 53 health checks

You have two web servers in different regions behind Route 53. You want DNS to route traffic only to healthy servers automatically. Which setup achieves this?

A Create two A records with failover routing and health checks on each server.

B Create two A records with latency routing and health checks on each server.

C Create one A record pointing to both servers without health checks.

D Create two A records with weighted routing and no health checks.

💡 Hint

Latency routing combined with health checks improves fault tolerance across regions.

Latency routing directs users to the lowest latency region. Adding health checks ensures traffic is only routed to healthy endpoints, providing fault tolerance.

❓ security

advanced

Security considerations for Route 53 health checks

Which security practice is important when configuring Route 53 health checks for your private web servers?

A Restrict health check requests to Route 53 health check IP ranges using firewall rules.

B Disable authentication on the health check endpoint to avoid failures.

C Allow all IP addresses to access the health check endpoint.

D Use HTTP instead of HTTPS to simplify health check configuration.

💡 Hint

Think about limiting who can reach your health check endpoint.

Restricting access to only Route 53 health check IPs prevents unauthorized access and protects your private servers.

✅ Best Practice

expert

Optimizing Route 53 health check intervals and failure thresholds

You want Route 53 to detect unhealthy endpoints quickly but avoid false positives from brief outages. Which combination of health check settings balances this best?

A Set interval to 60 seconds and failure threshold to 1.

B Set interval to 10 seconds and failure threshold to 1.

C Set interval to 5 seconds and failure threshold to 5.

D Set interval to 30 seconds and failure threshold to 3.

💡 Hint

Consider how often checks run and how many failures trigger unhealthy status.

A 30-second interval with 3 failures balances quick detection and reduces false alarms from transient issues.

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