2564209 - SYSTEM MANAGER: instance list does not contain SUM central instance

Following error occurs during SUM run in step PREP_PRE_CHECK INSTANCELIST_INIT:

   Directory: /usr/sap/<SID>/SUM/abap/log
   Name: SAPup.log
   ...
   CURRENTPHASE PREP_PRE_CHECK/INSTANCELIST_INIT
   ...started at 20171115120525
   # Using phase log file 'INSTANCELIST_INIT.LOG'.
   ...finished at 20171115120531 with status ABORTED.
   # Error message set: 'SYSTEM MANAGER: instance list does not contain SUM central instance.'
   ...begin dialog at 20171115120532
 
   Directory: /usr/sap/<SID>/SUM/abap/log
   Name: INSTANCELIST_INIT.LOG
   ...
   1 ETQ399 SYSTEM MANAGER: Instance list contains type: CI_NO DIAG_YES.
   1 ETQ399 SYSTEM MANAGER: Instance list contains type: CI_NO DIAG_YES.
   1EETQ399 SYSTEM MANAGER: initialize instance list has failed.
   1EETQ399 SYSTEM MANAGER: instance list does not contain SUM central instance.
   1EETQ399 Last error code set is: SYSTEM MANAGER: instance list does not contain SUM central instance.
 

• The SAP system consists of several instances on different servers.
• sapcontrol -nr <instance number> -function GetSystemInstanceList returns the instance list only partly, but some of the are missing.

For example,
in SM51 following three instances appear:

<host1>_<SID>_00 <host1> Dialog Batch Update Upd2 Spool ICM Active
<host2>_<SID>_00 <host2> Dialog Batch Update Upd2 Spool ICM Active
<host3>_<SID>_00 <host3> Dialog Batch Update Upd2 Spool ICM VMC Active

GetSystemInstanceList webmethod returns only two of them, the third one is missing:

sapcontrol -nr 0 -function GetSystemInstanceList

15.11.2017 14:06:09
GetSystemInstanceList
OK
hostname, instanceNr, httpPort, httpsPort, startPriority, features, dispstatus
<host1>, 0, 50013, 50014, 3, ABAP GATEWAY ICMAN IGS, GREEN
<host2>, 0, 50013, 50014, 3, ABAP GATEWAY ICMAN IGS, GREEN

It can also happen that all the available instances are recognized by SUM but none of them is treated as "central instance".

• UNIX operating systems
• Software Update Manager
• SAP NetWeaver all versions and all products running on top of them

UID GID, nslookup, loopback, /etc/hosts, 127.0.0.2 , KBA , BC-UPG-TLS-TLA , Upgrade tools for ABAP , BC-CST-STS , Startup Service , Problem