Failed to shutdown DBConsole Gracefully

Environment:
Oracle:
Oracle 10g Release 2  10.2.0.5
OS:
Linux
Summary:
Fix Oracle EM problem:Failed to shutdown DBConsole Gracefully

Today on a Linux Oracle machine without Oracle Enterprise Manger, I would like to install Oracle EM.

Use command

emca -config dbcontrol db -repos create

It reports an error

- An instance of Oracle Enterprise Manager 10g Database Control is already running.

It is strange that I have never create or start an EM process.

So I try to stop the existing EM process

SQL> emctl stop dbconsole
Oracle Enterprise Manager 10g Database Control Release 10.2.0.5.0
Copyright (c) 1996, 2006 Oracle Corporation.  All rights reserved.
http://oracletest:1158/em/console/aboutApplication
Stopping Oracle Enterprise Manager 10g Database Control …
— Failed to shutdown DBConsole Gracefully —
failed.

It fails, and also fails when I want to start EM

SQL> emctl start dbconsole
Oracle Enterprise Manager 10g Database Control Release 10.2.0.5.0
Copyright (c) 1996, 2006 Oracle Corporation.  All rights reserved.
http://oracletest:1158/em/console/aboutApplication
– An instance of Oracle Enterprise Manager 10g Database Control is already running.

A metalink doc tells us, it may happens when /etc/hosts file does not have following rows

127.0.0.1    localhost.localdomain  localhost

The  metalink doc also tells us to check file emctl.pid

Under $ORACLE_HOME/$HOST_$ORACLE_SID, for example in my host under /oracle/app/oracle/product/10.2.0/oracletest_mes

/oracle/app/oracle/product/10.2.0/oracletest_mes> cat emctl.pid

36599

Use ps –ef to check 36599 process, it is really not a oracle EM dbconsole process,so that’s why emctl stop dbconsole can not stop its instance.

Delete emctl.pid, emctl stop dbconsole succeed.

But when recreate dbconsole, it fails again and show error that the port 3938 has been used.

Check $ORACLE_HOME/install/portlist.ini

Enterprise Manager Console HTTP Port (mes) = 1158

Enterprise Manager Agent Port (mes) = 3938

It tells us EM agent use 3938 port, that means EM has 2 processes, one is for dbconsole, and one is for emagent. So you know how to do next, kill emagent process and recreate dbconsole. And this time, everything is OK.