Spring Boot 3.0 + AKS = always 200 with empty response

Question

I'm asking for your help for a very strange situation I'm having, after upgrading a microservice to Spring Boot 3.0, from 2.7.x version.

The microservice is deployed on AKS cluster, and, when I invoke any endpoint exposed by the microservice from the context-root, with any cookie , i always obtain a http status code 200 - OK with empty response, instead of the response i expect; this also happens to me when i invoke endpoints not exposed by the microservice. If instead I invoke the same endpoints without cookies , everything works correctly.

However, when I test the microservice endpoints locally (start in local debug) with new Spring Boot version (3.0.0) or when I rollback the microservice to the previous Spring Boot version (2.7.x) and deploy it on AKS cluster, everything works fine, both with and without cookies.

So I don't understand if the "problem" is on Spring Boot framework update or AKS/istio (kube ingress).

Here are some examples for clarity:

curl --request GET --url http://localhost:8080/endpoint -H "cookie: key=test"
{"out": "value"}

curl --request GET --url http://localhost:8080/endpoint
{"out": "value"}

this is OK!

curl --request GET --url http://my.ingress.com/context-root/endpoint -H "cookie: key=test"
(200 with empty response)

curl --request GET --url http://my.ingress.com/context-root/endpoint
{"out": "value"}

this is strange !

You are my last hope: :D Many thanks in advance

Answer 1

We ran into the same issue last week, but with an ECS cluster. Do you happen to have a DataDog tracing agent being deployed alongside your service? Someone had a similar issue and their solution was to bump the agent version to 1.3.0 . We bumped our agent to 1.4.0 and that fixed our issue.

The root cause could probably be traced back to this change if I had to guess