Friday, April 24, 2015

-Dweblogic.jdbc.ignoreExceptionsWhileCreatingInitialCapacity=true

I have just discovered the existence of this flag -Dweblogic.jdbc.ignoreExceptionsWhileCreatingInitialCapacity=true , whose name is quite self explanatory. However I found no documentation on it.
There is a note (Doc ID 1557843.1) in support saying that this flag is not supported and not really recommended.
I have personally always used InitialCapacity = 0, I don't care so much about losing performance on the first connection, I hate the AppServer to go in FAILED state if only ONE Datasource (which might be used only in some rare use case) is not available...
But again you MIGHT need this flag for special cases.... so.... do as you like, just don't rely too much on this flag...
See also -Dweblogic.deployment.IgnorePrepareStateFailures=true to the same purpose.

/dev/random story reloaded

If a t3s protocol is used -> SSL requires Random Numbers -> it's important to check that famous /dev/random story.
first check if the JVM is using /dev/random or /dev/urandom
doing lsof -p PID | grep random can show you which Randomness source the JVM is using
To check the performance of /dev/random on your specific machine, check how fast this command returns:
head -n 1 /dev/random
check that you have:
-Djava.security.egd=file:/dev/./urandom

it should be configured in : /opt/java/jdk160_85-64b/jre/lib/security/java.security
see also http://docs.oracle.com/cd/E13209_01/wlcp/wlss30/configwlss/jvmrand.html

Monday, April 13, 2015

WebLogic deployment with Docker



I am just reblogging this very interesting video (my compliments to Monica Riccelli) about WebLogic deployment with Docker.

Amazing how things are moving fast with Docker.... I really wonder if this Docker technology will really be widely adopted, or if it's mostly hype. I am not an expert so I just eat popcorn and enjoy the show.