AWS EC2 with Load Balancer

Question

I am used to linking my EC2 instances with my test load balancer (ACM effective) via target groups. But for some reason, a specific EC2 is causing 502 gateway once I link it as mentioned. The target application is WordPress. In specific, I have an HTTP rule that redirects to HTTPS.

Accepted Answer

Hello.

**Health Check Failures:**
ALB requires instances to pass health checks to route traffic to them.
Make sure that the health check endpoint is correctly set up in the target group. For WordPress, it might be something as simple as / or /wp-admin.
Check the health check path, protocol, port, and other parameters to ensure they are correct. Make sure the health check endpoint on the WordPress site responds with a 200 OK.

**Security Groups:**
Ensure that the security group attached to your EC2 instance allows traffic from the ALB. Usually, this means allowing traffic from the security group that's attached to your ALB to your EC2 instance on the port your web server is listening on.

Regards, Andrii

Answer

There is article about HTTP 502 errors when using ALB.

>How do I troubleshoot Application Load Balancer HTTP 502 errors?
https://repost.aws/knowledge-center/elb-alb-troubleshoot-502-errors

How about referring this post?

AWS EC2 with Load Balancer

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