Cluster Master, Singleton Master....

taking sparse notes here...

Cluster Master:

http://docs.oracle.com/cd/E21764_01/web.1111/e13709/migration.htm#i1034621
"Its role is to orchestrate the server migration process"
Reading this doc is like pure poetry.



Singleton Master:

http://docs.oracle.com/cd/E21764_01/web.1111/e13709/service_migration.htm#i1051470

"The singleton master is a lightweight singleton service that monitors other services that can be migrated automatically."

These services use the ACTIVE Database table to keep renewed the lease:

CREATE TABLE ACTIVE (
SERVER VARCHAR2(150) NOT NULL,
INSTANCE VARCHAR2(100) NOT NULL,
DOMAINNAME VARCHAR2(50) NOT NULL,
CLUSTERNAME VARCHAR2(50) NOT NULL,
TIMEOUT DATE,
PRIMARY KEY (SERVER, DOMAINNAME, CLUSTERNAME)
);


see /opt/oracle/fmw11_1_1_5/wlserver_10.3/server/db/oracle/920/leasing.ddl

and the content of the table looks like:

"SERVER"                      "INSTANCE"                    "DOMAINNAME"                  "CLUSTERNAME"                 "TIMEOUT"                    

"service.SINGLETON_MASTER"    "2756549746869550668/osbpp1ms1""osbpp1do"                    "osbpp1cl"                    "06-MAY-12"                  

"wlsserver.osbpp1ms4"         "-5012701700773599167/osbpp1ms4""osbpp1do"                    "osbpp1cl"                    "06-MAY-12"                  

"service.CLUSTER_MASTER"      "2756549746869550668/osbpp1ms1""osbpp1do"                    "osbpp1cl"                    "06-MAY-12"                  

"wlsserver.osbpp1ms2"         "1291378860276628438/osbpp1ms2""osbpp1do"                    "osbpp1cl"                    "06-MAY-12"                  

"wlsserver.osbpp1ms1"         "2756549746869550668/osbpp1ms1""osbpp1do"                    "osbpp1cl"                    "06-MAY-12"                  

"wlsserver.osbpp1ms3"         "-2011604050071714597/osbpp1ms3""osbpp1do"                    "osbpp1cl"                    "06-MAY-12"               


that is, one row per managed server in the cluster, plus a row for service.SINGLETON_MASTER and one for service.CLUSTER_MASTER (this is also telling us that both SINGLETON_MASTER and CLUSTER_MASTER are osbpp1ms1 in this case.