For my JUnit tests, I have configured a logback-test.xml file with only a <consolePlugin/> entry. (debug=false)
However, when I run the tests on the build-server, I get the following printed to System.out:

09:02:23,596 |-ERROR in ch.qos.logback.classic.net.SocketAppender[null] - Could not connect to remote logback server at [localhost]. We will try again later.
java.net.ConnectException: Connection refused: connect
       at java.net.ConnectException: Connection refused: connect
       at at java.net.PlainSocketImpl.socketConnect(Native Method)
       at at java.net.PlainSocketImpl.doConnect(PlainSocketImpl.java:333)
       at at
java.net.PlainSocketImpl.connectToAddress(PlainSocketImpl.java:195)

I realize that this message is part of logbacks internal status, however it would be nice to have the option to disable this message which pollutes the build-log on the build-server. Maybe by specifying an attribute like this: <consolePlugin silent="true"/> where the underlying Socketappender will be silent if it is not able to connect to the host and port.

I'll see if I can upload a patch later today.
Regards,
Paul Nyheim