GKE MultiClusterIngress with HTTP/3 support

Question

I'm using GKE's MultiClusterIngress to set up a load balancer that routes traffic to the closest GKE cluster. The load balancer set up by MultiClusterIngress advertises HTTP/3 (QUIC) support in the alt-svc header. However when using curl with --http3 , I am unable to connect:

* Connect socket 5 over QUIC to [redacted]:443
* connect to [redacted] port 443 failed: Failure when receiving data from the peer
* Failed to connect to [redacted] port 443 after 127 ms: Failure when receiving data from the peer

If I query the created load balancer using gcloud , I see that it has quicOverride set to NONE , which according to the docs means that it should support QUIC.

How do I get QUIC working?

Answer 1

I was hitting the load balancer using its IP address instead of using a valid DNS name. Setting up DNS and using that works as expected.

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If somebody is familiar with how QUIC works, I'd love to understand why setting the Host header is not sufficient to set up a connection.