Reference Documentation Felix RootCause

Finding the root cause of problems with OSGi declarative services components.


  • Configuration Admin Service
  • Service Component Runtime

See below for a hands on example in Apache Karaf.

Root cause command

For quickly checking for a root cause of a problem with a declarative services component there is also a handy command.

rootcause <ds-compoment-name>

It prints the top level status of a DS component as well as the tree of DS unsatisfied components it depends on together with their status.

This is a sample output from the DSRootCause tests. It shows the cause of a component that depends on some other components. The root cause of CompWithMissingRef2 not being satisfied is that CompWithMissingConfig is missing its mandatory config.

Component CompWithMissingRef2 unsatisfied references
  ref other interface CompWithMissingRef
    Component CompWithMissingRef unsatisfied references
      ref other interface CompWithMissingConfig
        Component CompWithMissingConfig missing config on pid [CompWithMissingConfig]

Example of using the system ready service framework in Apache Karaf

Download, install and run Apache Karaf 4.1.x. Inside the karaf shell execute this:

feature:install scr http-whiteboard
config:property-set --pid ServicesCheck services.list org.osgi.service.log.LogService
config:property-set --pid SystemReadyServlet "("
install -s mvn:org.apache.felix/org.apache.felix.systemready/0.1.0-SNAPSHOT

Point your browser to http://localhost:8181/system/console/ready .

Check the status of a DS component:

rootcause SystemReadyMonitor
 Component SystemReadyMonitor statisfied

Try this with some of your own components.