K8s Headers Forwarding Configuration

TODO: collapasable, copyable, download, etc

I am using kubernets and a kubernetes load balancer with my nodejs app. If I request https://example.com, my NodeJS server thinks it is a request for localhost:8081.

If I deploy the same code behind an AWS ELB load balancer, it thinks the request is for example.com. What is missing in the kubernetes side?In Kubernetes, when you're experiencing an issue where your application thinks it's receiving requests for localhost:8081 instead of the actual domain https://example.com, it often points to how headers are being handled and forwarded by your ingress controller or load balancer setup. Here's a checklist of what might be missing or what you should verify in your Kubernetes setup compared to an AWS Elastic Load Balancer (ELB) setup:

1. Ingress Controller Configuration: Ensure that your Kubernetes ingress controller is properly configured to forward the Host header. The Host header is crucial for your application to understand the original domain the request was made to. Ingress controllers like NGINX, Traefik, or others have configurations to preserve or forward the original Host header.

2. X-Forwarded-For and X-Forwarded-Proto Headers: ELB automatically sets the X-Forwarded-For and X-Forwarded-Proto headers to maintain the original request's IP and protocol (HTTP or HTTPS). You should ensure that your Kubernetes ingress controller is configured to set or forward these headers as well. These headers allow your application to understand the original client IP and whether the request was made over HTTP or HTTPS.

3. Proxy Protocol: AWS ELB supports the Proxy Protocol, which provides additional information about the client request, such as the original IP and port. If you're relying on this information, ensure your Kubernetes ingress or load balancer supports and is configured to use the Proxy Protocol.

4. Service Type: In Kubernetes, services can be exposed using different types like ClusterIP, NodePort, and LoadBalancer. When using a LoadBalancer service in AWS, ELB is automatically configured. Ensure your service is correctly set up to use an external load balancer and that your ingress is correctly routing requests to your application.

5. Application Code: Sometimes, the issue might be in how your application interprets headers. Ensure your Node.js application is correctly configured to trust the headers set by your ingress controller. If you're using Express.js, for example, you might need to use app.set('trust proxy', true); to ensure your application trusts the X-Forwarded-* headers.

6. Annotations: Kubernetes ingress objects allow annotations that customize behavior for specific ingress controllers. Check if there are any annotations that your ingress controller supports to better handle forwarding headers or the original host information.

7. ExternalDNS (if applicable): If you're using ExternalDNS to manage DNS records for services or ingresses in Kubernetes, ensure it's correctly configured to point your domain to the right resources.

In summary, the issue likely revolves around how your ingress controller in Kubernetes is handling headers compared to AWS ELB. By ensuring that your Kubernetes setup correctly forwards and respects headers like Host, X-Forwarded-For, and X-Forwarded-Proto, you can achieve the same behavior as seen with AWS ELB.I am using nohup sh -C 'GOOGLE_OAUTH_CLIENT_ID=532462978790-khsmqpabem82k4ru1ikl7591h8idnvu2.apps.googleusercontent.com GOOGLE_OAUTH_SECRET=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 AUTH_SECRET=98db4f30dc8c6e9f9dcc3bf56d7fc250b0eecafe1370339e0249f696d2c862c1 PORT=5173 node build' &,but when I exit the terminal, the server stopsWhen you run a command using nohup in the background (with &), it's supposed to detach the process from the terminal so that the process continues running even if the terminal is closed. However, there might be a few reasons why your server stops after you exit the terminal, despite using nohup:

1. Process Management: nohup does not fully daemonize your process; it merely ignores the HUP (hangup) signal. This means that while the process will ignore terminal closure, it might not handle other aspects of running in the background correctly, such as log handling or if it tries to read from stdin.

2. Incorrect Command Syntax: The use of sh -C (with capital C) in your command seems unusual. Typically, the -c option (lowercase) is used to pass a command to sh. The case sensitivity might affect how the command is interpreted. Ensure that you're using the correct options for your shell.

3. Environment Variables: Setting environment variables inline with nohup and backgrounding might not work as expected in all shells. The environment variables could be lost when the shell session is terminated.

4. Output Redirection: By default, nohup redirects the standard output (stdout) and standard error (stderr) to a file named nohup.out in the current directory. If there are issues with writing to this file, or if the process generates output that isn't correctly handled, it might cause problems.

To address these issues, try the following:

1. Fix the Command Syntax: Use lowercase -c with sh, and ensure your command syntax is correct:

nohup sh -c 'GOOGLE_OAUTH_CLIENT_ID=532462978790-khsmqpabem82k4ru1ikl7591h8idnvu2.apps.googleusercontent.com GOOGLE_OAUTH_SECRET=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 AUTH_SECRET=98db4f30dc8c6e9f9dcc3bf56d7fc250b0eecafe1370339e0249f696d2c862c1 PORT=5173 node build' &

2. Ensure Environment Variables Persist: Consider exporting the environment

K8s Headers Forwarding Configuration created at Tue Jan 20 1970 18:26:59 GMT+0000 (Coordinated Universal Time)