Health checks configuration in GCP - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ service_behavior

intermediate

Understanding HTTP Health Check Behavior

You configure an HTTP health check for a Google Cloud Load Balancer with the following settings:

• Request path: /status
• Port: 8080
• Check interval: 10 seconds
• Timeout: 5 seconds
• Unhealthy threshold: 3
• Healthy threshold: 2

If your backend service responds with HTTP 200 to /status for 1 check, then returns HTTP 500 for the next 3 checks, what will be the health status of the backend after these 4 checks?

A The backend becomes unhealthy after 3 consecutive unhealthy responses.

B The backend remains healthy because only 1 unhealthy response occurred.

C The backend becomes unhealthy immediately after the first unhealthy response.

D The backend status is unknown because the healthy threshold is 2.

💡 Hint

Consider how the unhealthy threshold affects status changes.

The backend must fail 3 consecutive health checks to be marked unhealthy. After 1 healthy and then 3 unhealthy responses, the backend becomes unhealthy.

❓ Configuration

intermediate

Configuring a TCP Health Check in GCP

You want to create a TCP health check for a backend service that listens on port 3306. Which of the following YAML snippets correctly defines this health check in a Deployment Manager template?

A

type: compute.v1.healthCheck
properties:
  name: tcp-health-check
  tcpHealthCheck:
    port: "3306"
  checkIntervalSec: 10
  timeoutSec: 5
  unhealthyThreshold: 3
  healthyThreshold: 2

B

type: compute.v1.healthCheck
properties:
  name: tcp-health-check
  httpHealthCheck:
    port: 3306
  checkIntervalSec: 10
  timeoutSec: 5
  unhealthyThreshold: 3
  healthyThreshold: 2

C

type: compute.v1.healthCheck
properties:
  name: tcp-health-check
  tcpHealthCheck:
    port: 3306
  checkIntervalSec: 10
  timeoutSec: 5
  unhealthyThreshold: 3
  healthyThreshold: 2

D

type: compute.v1.healthCheck
properties:
  name: tcp-health-check
  tcpHealthCheck:
    port: 3306
  checkIntervalSec: "10"
  timeoutSec: 5
  unhealthyThreshold: 3
  healthyThreshold: 2

💡 Hint

Check the correct health check type and data types for port and intervals.

The TCP health check must use tcpHealthCheck with port as an integer. The check interval and timeout must also be integers, not strings.

❓ Architecture

advanced

Designing Health Checks for Multi-Region Backends

You have a multi-region backend service deployed in two Google Cloud regions. You want to ensure that the load balancer only sends traffic to healthy backends in each region. Which health check design best supports this goal?

A Create separate health checks for each region's backend with region-specific settings.

B Disable health checks and rely on backend logs to detect failures.

C Use a single global health check shared by all backends in both regions.

D Use a single health check but configure it to check multiple ports on all backends.

💡 Hint

Think about how health checks can reflect regional backend health independently.

Separate health checks per region allow the load balancer to detect and route traffic only to healthy backends in each region, improving reliability and performance.

❓ security

advanced

Securing Health Check Endpoints

Your backend service exposes an HTTP health check endpoint at /health. To improve security, you want to restrict access so only Google Cloud health check probes can reach it. Which approach is best?

A Disable health checks and rely on backend logs for health monitoring.

B Configure firewall rules to allow traffic to <code>/health</code> only from Google Cloud health check IP ranges.

C Require a username and password on the <code>/health</code> endpoint for all requests.

D Make the <code>/health</code> endpoint publicly accessible without restrictions.

💡 Hint

Consider how to limit network access to trusted sources.

Google publishes IP ranges for health check probes. Restricting access by firewall rules to these IPs protects the health check endpoint from unauthorized access.

✅ Best Practice

expert

Optimizing Health Check Configuration for Cost and Performance

You manage a backend service with many instances behind a Google Cloud Load Balancer. You want to optimize health check settings to reduce cost and avoid false positives without sacrificing reliability. Which combination of settings is best?

A Set check interval to 1 second, timeout to 1 second, unhealthy threshold to 1, healthy threshold to 1.

B Set check interval to 5 seconds, timeout to 1 second, unhealthy threshold to 1, healthy threshold to 1.

C Set check interval to 10 seconds, timeout to 10 seconds, unhealthy threshold to 3, healthy threshold to 3.

D Set check interval to 30 seconds, timeout to 5 seconds, unhealthy threshold to 5, healthy threshold to 2.

💡 Hint

Balance frequency and thresholds to reduce load and avoid flapping.

Longer intervals and higher thresholds reduce health check traffic and avoid marking backends unhealthy due to transient issues, balancing cost and reliability.