EM 默认的节点是 节点 1，现更改默认的节点为节点 2。

注意下面的语法：EM_NODE 是节点名，EM_SID_LIST 后面接的是 SID

[oracle@PTFDB1 ~]$ emca -reconfig dbcontrol -cluster -EM_NODE ptfdb2 -EM_SID_LIST ptfdb1


STARTED EMCA at Jan 20, 2016 2:12:28 AM
EM Configuration Assistant, Version 11.2.0.3.0 Production
Copyright (c) 2003, 2011, Oracle.  All rights reserved.


Enter the following information:
Database unique name: ptfdb
Service name: ptfdb
Agent Node list [comma separated] (optional): ptfdb1,ptfdb2
Do you wish to continue? [yes(Y)/no(N)]: Y
Jan 20, 2016 2:12:47 AM oracle.sysman.emcp.EMConfig perform
INFO: This operation is being logged at /u01/app/oracle/cfgtoollogs/emca/ptfdb/emca_2016_01_20_02_12_28.log.
Jan 20, 2016 2:12:50 AM oracle.sysman.emcp.util.DBControlUtil stopOMS
INFO: Stopping Database Control (this may take a while) ...
Jan 20, 2016 2:12:54 AM oracle.sysman.emcp.EMAgentConfig performDbcReconfiguration
INFO: Propagating /u01/app/oracle/product/11.2.0/db_1/ptfdb1_ptfdb/sysman/config/emd.properties,/u01/app/oracle/product/11.2.0/db_1/ptfdb2_ptfdb/sysman/config/emd.properties to remote nodes ...
Jan 20, 2016 2:12:54 AM oracle.sysman.emcp.util.DBControlUtil startOMS
INFO: Starting Database Control (this may take a while) ...
Jan 20, 2016 2:13:33 AM oracle.sysman.emcp.EMDBPostConfig performDbcReconfiguration
INFO: Database Control started successfully
Jan 20, 2016 2:13:33 AM oracle.sysman.emcp.EMDBPostConfig showClusterDBCAgentMessage
INFO: 
****************  Current Configuration  ****************
 INSTANCE            NODE           DBCONTROL_UPLOAD_HOST
----------        ----------        ---------------------


ptfdb             ptfdb1             PTFDB2
ptfdb             ptfdb2             PTFDB2


Enterprise Manager configuration completed successfully
FINISHED EMCA at Jan 20, 2016 2:13:33 AM
[oracle@PTFDB1 ~]$ emctl status dbconsole
Oracle Enterprise Manager 11g Database Control Release 11.2.0.3.0 
Copyright (c) 1996, 2011 Oracle Corporation.  All rights reserved.
https://PTFDB2:1158/em/console/aboutApplication
EM Daemon is running. 
------------------------------------------------------------------
Logs are generated in directory /u01/app/oracle/product/11.2.0/db_1/ptfdb1_ptfdb/sysman/log