:index-group: Discovery and Failover
:jbake-date: 2018-12-05
:jbake-type: page
:jbake-status: published

Setting the following logging category to "debug" will open up some new
logging information.

[source,properties]
----
log4j.category.OpenEJB.server.discovery = debug
----

Or more specifically as:

[source,properties]
----
log4j.category.OpenEJB.server.discovery.multipoint = debug
log4j.category.OpenEJB.server.discovery.multicast = debug
----

The nature of the debug output is to display all configuration
information at startup:

[source,properties]
----
DEBUG - Using default 'heart_rate=500'
DEBUG - Using default 'max_missed_heartbeats=10'
DEBUG - Using default 'max_reconnect_delay=30000'
DEBUG - Using default 'reconnect_delay=5000'
DEBUG - Using default 'exponential_backoff=0'
DEBUG - Using default 'max_reconnect_attempts=10'
INFO - Created Tracker{group='default', groupPrefix='default:', heartRate=500, maxMissedHeartbeats=10, reconnectDelay=5000, maxReconnectDelay=30000, maxReconnectAttempts=10, exponentialBackoff=0, useExponentialBackOff=false, registeredServices=0, discoveredServices=0}
----

Changing the configuration should reflect in the logging as follows:

[source,properties]
----
INFO - Using 'heart_rate=200'
INFO - Using 'max_missed_heartbeats=2'
DEBUG - Using default 'max_reconnect_delay=30000'
DEBUG - Using default 'reconnect_delay=5000'
DEBUG - Using default 'exponential_backoff=0'
DEBUG - Using default 'max_reconnect_attempts=10'
INFO - Created Tracker{group='default', groupPrefix='default:', heartRate=200, maxMissedHeartbeats=2, reconnectDelay=5000, maxReconnectDelay=30000, maxReconnectAttempts=10, exponentialBackoff=0, useExponentialBackOff=false, registeredServices=0, discoveredServices=0}
----

As well as any events at runtime:

[source,properties]
----
DEBUG - Expired Service{uri=green://localhost:0, broadcastString='default:green://localhost:0&#39;} Timeout{lastSeen=-5005, threshold=5000}

DEBUG - Added Service{uri=green://localhost:0}

DEBUG - Removed Service{uri=green://localhost:0}
----