2835594 - Load balance of HTTP/HTTPS within multiple instances does not work

When end users connect through load balance tool via HTTP/HTTPS, for example SAP Web Dispatcher, the requests never reach one instance even the instance is running correctly.

 The application server list of message server shows that several instances running on the same server, even though these instances are seperated on different servers, for example:

instance 01 and instance 02 are running on hostname1 and hostname2 respectively, but we could see the same hostname for the 2 instances in the application server list via message server URL:

http://<message server host name>:<message server HTTP port>/msgserver/text/logon?version=1.2

  version 1.2
  <hostname1>_<SID>_01
    HTTP hostname1 8001

  <hostname2>_<SID>_02
    HTTP hostname1 8001

 If you are using WDP, you could also see the same hostname for 2 instances via WDP checkconfig "sapwebdisp -checkconfig pf=<WDP profile>":

+---------------------+---------------------+----------+------------+
| instance name   | hostname       |HTTP port|HTTPS port|
+---------------------+---------------------+----------+------------+
|       instance01  |<hostname1>   |   8001  |              |
|       instance02  |<hostname1>   |   8001  |              |
+---------------------+---------------------+----------+------------+

 Load balance, application server list, icm/host_name_full , KBA , BC-CST-IC , Internet Communication Manager , Problem