I have a spring boot application that is running in google cloud run and is using http2. The problem is that I get a lot of these messages in the logs:
Connection [2], An unknown setting with identifier [8] and value [1] was ignored
I have the http/2 flag enabled in spring:
server.http2.enabled=true
Also i have the http/2 flag activated in the network tab in the cloud run configuration of the service.
I also use http/2 to get around the 32MB limit that google imposes on the http 1.1 connections and it works fine.
I used the curl command from this issue (Curl: one-liner to test http/2 support) to test and get back that it should understand http/2:
curl -sI https://*******.run.app/testCall -o/dev/null -w '%{http_version}\n'
2
when running it I get a 2 back which should indicate that my application understands http/2.
And as said the command is executed fine, the problem is that per call you get a warning in the log and I'd like to find out where the fault is, since this issue (An unknown setting with identifier [8] and value [0] was ignored) seems to indicate that it is a misconfiguration of client, but I only use curl directly on the url given by google.
In the latest versions of tomcat this is no longer a warning. see: github tomcat commit
So it is save to ignore this warning or suppress.