Quick Summary
In this article, we’ll break down how AWS health checks keep your application running smoothly by automatically monitoring resources like servers and containers. You’ll learn about the specific AWS services that use health checks, how they work, and best practices to ensure your app stays healthy.
Introduction
What happens if a server fails unnoticed? It can cause downtime and poor performance. AWS health checks solve this by automatically monitoring your resources. If something goes wrong, Amazon Web Services quickly takes action, rerouting traffic or scaling resources to ensure your app runs smoothly.
What are AWS Health Checks?
AWS health checks are a process used by AWS services to regularly check if parts of your application, like servers, containers, or functions, are working properly. This process helps ensure that your app stays available and runs smoothly.
These health checks monitor things like:
- Whether a server is responding.
- If a website is loading properly.
- If containers are running as expected.
Many AWS services, such as Elastic Load Balancing, EC2 Auto Scaling, ECS, and Route 53, have built-in health checks. Some services require you to turn them on or adjust settings, while others manage the checks automatically.
If a problem is found, like a server not responding, the AWS service can stop sending traffic to it and switch to another healthy part of your system. This ensures your app remains operational without any user interruptions.
In simple terms, AWS health checks are an ongoing process that helps keep your app healthy and online.
How AWS Services Perform Health Checks
This section will explain how various AWS services, including Elastic Load Balancing (ELB), EC2 Auto Scaling, Amazon ECS, Route 53, and others, handle health checks to ensure the reliability and performance of your application.
1. Elastic Load Balancing (ELB)
Purpose: ELB shares incoming traffic across multiple servers to prevent any one from getting overloaded.
How It Checks Health:
- It regularly sends test requests (called health checks) to each server it’s connected to.
- These checks are like asking, “Are you okay?” If a server doesn’t answer correctly or quickly enough, it’s marked as unhealthy.
- Traffic is instantly stopped from going to that unhealthy server and redirected to other healthy ones.
How It Reacts:
- Keeps your app running smoothly by only sending traffic to servers that are working well.
- Helps prevent app crashes during high traffic by spreading the load.
Why It’s Special:
- It works live, handling real-time traffic.
- It supports different types:
• Application Load Balancer: Ideal for modern web apps. It routes traffic based on content like URLs or user information.
• Network Load Balancer: Designed for high-performance apps needing ultra-low latency.
• Classic Load Balancer: The original type, best suited for simpler workloads.
- It’s built to handle sudden traffic spikes without slowing down your users.
2. Amazon EC2 Auto Scaling
Purpose: Automatically adds or removes virtual servers (EC2 instances) based on how busy your app gets.
How It Checks Health:
- Watches server performance closely – checking CPU usage, response times, and whether the server is working.
- Also listens to feedback from Load Balancers about the unhealthy server status.
- If a server crashes or becomes too slow, it’s replaced with a new one.
How It Reacts:
- Grows or shrinks your group of servers automatically depending on how much work your app needs to handle.
- Replaces any broken or unhealthy server quickly to avoid downtime.
Why It’s Special:
- It’s not just about checking – it automatically takes action.
- Perfect for businesses where traffic goes up and down often.
- Helps save money too, because it only runs the number of servers you actually need.
3. Amazon EKS (Elastic Kubernetes Service)
Purpose: Amazon EKS helps you run apps in containers using Kubernetes – a system that manages thousands of small app pieces.
How It Checks Health:
- Uses Kubernetes health checks (called liveness and readiness probes) to monitor every small part of your app (called pods).
- Checks if a pod is active, responsive, and ready to accept traffic.
- Also watches the machines (nodes) running the containers.
How It Reacts:
- Automatically restarts unhealthy pods or moves them to healthy machines.
- Keeps your containerized app balanced and running even if parts fail.
- Works with Load Balancers to make sure only healthy pods get traffic.
Why It’s Special:
- Gives deep control over complex, large-scale apps running in containers.
- It’s designed for developers already using Kubernetes but wants AWS to handle the heavy lifting.
- Offers smooth scaling and automatic self-healing at both the container and server levels.
4. AWS Lambda
Purpose: It lets you run code without managing any servers- it just runs when something triggers it (like a user clicking a button).
How It Checks Health:
- Watches every single time your code runs.
- Checks for errors like timeouts, failures, or wrong outputs.
- Logs every issue in detail so you can review and fix it.
How It Reacts:
- Automatically retries the failed code execution (if set to do so).
- Stops unhealthy code if it’s failing consistently.
- Can trigger alerts or send logs to other services for review.
Why It’s Special:
- It’s serverless, which means you don’t worry about machines at all.
- Ideal for small, quick jobs like handling user requests, automating tasks, or connecting services.
- Scales instantly to handle thousands of requests at once, with zero manual setup.
5. AWS Global Accelerator
Purpose: Speeds up and improves the reliability of your application for users around the world.
How It Checks Health:
- Constantly checks the health of your app’s endpoints (like load balancers, EC2, or other services).
- Uses AWS’s private global network to test which region or server is responding fastest and healthiest.
- Detects failures or slowness instantly.
How It Reacts:
- Redirects users to the nearest and healthiest AWS region.
- Automatically removes failing endpoints from its path until they recover.
- Keeps your app available globally, even if one part of your setup goes down.
Why It’s Special:
- Unlike other tools, it optimizes global traffic using AWS’s fast internal network.
- Makes apps feel faster to users everywhere, especially in regions far from your original servers.
- Built for high availability and top performance at a global level.
AWS Health Checks Best Practices
To make the most out of AWS Health Checks and ensure your environment stays in top shape, follow these best practices:
- Monitor Regularly: Set up CloudWatch alarms to notify you of health check failures. Ongoing monitoring helps identify problems before they escalate.
- Automate Remediation: Use services like AWS auto scaling and Lambda to automatically replace or restart unhealthy resources.
- Adjust AWS Health Checks Thresholds: Customize your health check settings to avoid false positives and ensure that only truly unhealthy resources are flagged.
- Use Multiple Layers of Monitoring: Rely on multiple AWS services to monitor different aspects of your environment (e.g., EC2 for instances, ALB for traffic, Route 53 for DNS).
- Test and Validate: Regularly test your health check configurations to validate that they are working as expected and triggering the right actions.
- Review Logs: Use detailed logs and monitoring data to troubleshoot and fix issues quickly. Services like CloudWatch Logs and X-Ray can help.
Conclusion
AWS Health Checks help monitor the health and performance of your resources, ensuring everything runs smoothly and securely. If you want expert help setting it up and managing it effectively, AWS Managed Services can handle it for you.
They not only enhance visibility into your system’s health but also enable faster incident response and improved operational efficiency. Incorporating automated health checks into your cloud strategy ensures continuous performance optimization and a more resilient AWS environment.
