The ElasticBoxExecutor class extends the hudson AsyncPeriodicWork to run a task every 10 or so seconds. This leads to massive spam:

INFO: Started com.elasticbox.jenkins.ElasticBoxExecutor
May 12, 2015 9:04:39 PM hudson.model.AsyncPeriodicWork$1 run
INFO: Finished com.elasticbox.jenkins.ElasticBoxExecutor. 0 ms
May 12, 2015 9:04:49 PM hudson.model.AsyncPeriodicWork$1 run
INFO: Started com.elasticbox.jenkins.ElasticBoxExecutor
May 12, 2015 9:04:49 PM hudson.model.AsyncPeriodicWork$1 run
INFO: Finished com.elasticbox.jenkins.ElasticBoxExecutor. 0 ms
May 12, 2015 9:04:59 PM hudson.model.AsyncPeriodicWork$1 run
INFO: Started com.elasticbox.jenkins.ElasticBoxExecutor
May 12, 2015 9:04:59 PM hudson.model.AsyncPeriodicWork$1 run
INFO: Finished com.elasticbox.jenkins.ElasticBoxExecutor. 0 ms
May 12, 2015 9:05:09 PM hudson.model.AsyncPeriodicWork$1 run
INFO: Started com.elasticbox.jenkins.ElasticBoxExecutor
May 12, 2015 9:05:09 PM hudson.model.AsyncPeriodicWork$1 run
INFO: Finished com.elasticbox.jenkins.ElasticBoxExecutor. 0 ms

According to https://issues.jenkins-ci.org/browse/JENKINS-22132, this can be fixed if you...

just override getNormalLoggingLevel() and getNormalLoggingLevel() from https://github.com/jenkinsci/jenkins/blob/master/core/src/main/java/hudson/model/AsyncPeriodicWork.java in order to stop the [spam] in the console. Jenkins version should be at least 1.551 for this to work.