Yes. The default listening port (CAPort) of a custom runtime is 9000. If a custom runtime uses the default listening port, the listening port of its HTTP server must be 9000. If the listening port of the custom runtime is 8080, the listening port of its HTTP server must be 8080.
The HTTP server started in a custom runtime must listen on the
0.0.0.0:CAPort or *:CAPort port. If you select the 127.0.0.1:CAPort port, the request times out and the following error occurs:{
"ErrorCode":"FunctionNotStarted",
"ErrorMessage":"TheCA'shttpservercannotbestarted:ContainerStartDuration:25000000000.PingCAfaileddueto:dialtcp21.0.5.7:9000:getsockopt:connectionrefusedLogs:2019-11-29T09:53:30.859837462ZListeningonport9000"
}