I need help diagnosing a strange problem that started when I migrated from 1.7 to 2.2.
Problem:
Newly created cookies are not returned on the response to the browser. The application is running in a docker container and changing from Traefik 2.x back to 1.7 makes it work. Going back to 2.x breaks it again.
Additional Info:
Traefik is running inside Kubernetes. I have tested with both Ingress and the newer IngressRoute.
The application is a Rails app running inside a docker container. Inside the container it uses Nginx and Fusion Passenger to handle requests. When logging in to the application, a _session cookie is set. However, this cookie is not returned to the browser when using 2.x. I've tested setting other cookies and those are not returned either.
I haven't found documented issues or problems like this. I've re-deployed Traefik running with log.level=DEBUG but didn't see anything too helpful. The only thing I saw was that in the logs, Traefik lists the cookies returned on a redirect and the missing cookies are still missing from those logs.
I tested this with multiple versions of Traefik and confirmed that the problem started when moving from 1.7 to 2.0.
What can I do to help isolate this issue? Have you heard of anything like this before?
When I run Traefik locally on my machine using the same applications but not with Nginx/Passenger, it does return the cookies.