org.eclipse.virgo.medic.log.impl.logback.LoggerContextConfigurationFailedException: Configuration failed with the following problems: [Could not create an Appender of type [ch.qos.logback.core.Consoleappender]. Caused by java.lang.ClassNotFoundException: ch.qos.logback.core.Consoleappender., ActionException in Action for tag [appender] Caused by ch.qos.logback.core.util.DynamicClassLoadingException: Failed to instantiate type ch.qos.logback.core.Consoleappender.]

Finally, if your appenders are 'static' and you want to guarantee them to be available from the very start, logback does the loading of appenders from its classpath and the appenders need to be on the bundle classpath of the medic bundle. Without modifying medic what you do is to put the appender code in a fragment bundle and define medic as the host fragment. The fragment bundle is then deployed by putting it in the kernel region launch list. This effectively makes it part of the kernel.

If you want to dynamically add your appender to logback (using the addappender api on Logger) then there is no need to have a fragment bundle, just make sure that the appender is added when the appender bundle is started. In this last case, it is still necessary to put the appender code in the kernel launch list -- after the medic bundle.