So my two picks for the day are:
1. Starting and stopping individual applications.
Yes that's right! The opmnctl utility can start and stop individual applications running on an OC4J instance under the control of OPMN.
The command form is:
$opmnctl stopproc application=FOO
where FOO is the name of the application.
This will cause the FOO application to be shutdown and the setting persisted in the OC4J j2ee/home/config/server.xml so that the application will be kept in the last requested state if/when the OC4J instance itself is restarted.
This command is particularly useful if you have wired together a few 10.1.3 instances in which the "Application Server Control" is active on each instance and you receive a warning when you use it that there are multiple instances running. It's a bit of a pain since ASC won't let you stop an ASC application, even if its not the current one. Therefore to stop an instance of ASC from running you can use this nice opmnctl facility.
Go to the $ORACLE_HOME/opmn/bin directory of the instance in which you want to stop ASC and type
$ opmnctl stopproc application=ascontrol
opmnctl: stopping opmn managed processes...
Further, if you have access to one instance of opmnctl which is mapped into the topology then you don't even need to go into the specific $ORACLE_HOME directory of the instance where you want to stop ASC. You can just add an "instance" scope to the command and point it at the instance where you want to stop ASC.
2. Live reporting
The default mode of operation of opmnctl is to report the output of its operations when all of the operations have completed.
If you are like me and like to see results as they happen, then you can give opmnctl an extra switch and it'll report status as it receives it.
You can do this by tacking on the additional switch
It's a little hard to visualize this, but the following comes in on a line-by-line basis as the individual activities are finishing -- not as a result blob at the very end of the restartproc operation
$opmnctl @cluster restartproc report=true
opmnctl: restarting opmn managed processes...
060426_ohsj2ee.stadp57.us.oracle.com: 4 of 4 processes restarted.