JBoss EAP 6 stalls recursively scanning exploded deployment during startup

Solution Verified - Updated

Environment

  • JBoss Enterprise Application Platform (EAP) 6

Issue

We are deploying an application that has a symlink to NFS share with a very large number of files. JBoss hangs when starting the server.

In thread dumps, we see:

"DeploymentScanner-threads - 1" prio=10 tid=0x00007f0ad80e2800 nid=0x253e runnable [0x00007f0b18961000]
   java.lang.Thread.State: RUNNABLE
	at java.io.UnixFileSystem.list(Native Method)
	at java.io.File.list(File.java:973)
	at java.io.File.listFiles(File.java:1051)
	at org.jboss.as.server.deployment.scanner.FileSystemDeploymentService.getDeploymentTimestamp(FileSystemDeploymentService.java:770)
	at org.jboss.as.server.deployment.scanner.FileSystemDeploymentService.getDeploymentTimestamp(FileSystemDeploymentService.java:771)
	at org.jboss.as.server.deployment.scanner.FileSystemDeploymentService.getDeploymentTimestamp(FileSystemDeploymentService.java:771)
	at org.jboss.as.server.deployment.scanner.FileSystemDeploymentService.scanDirectory(FileSystemDeploymentService.java:567)
	at org.jboss.as.server.deployment.scanner.FileSystemDeploymentService.scan(FileSystemDeploymentService.java:360)
	at org.jboss.as.server.deployment.scanner.FileSystemDeploymentService.oneOffScan(FileSystemDeploymentService.java:335)
	at org.jboss.as.server.deployment.scanner.DeploymentScannerAdd$2.run(DeploymentScannerAdd.java:161)
	at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:439)
	at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:303)
	at java.util.concurrent.FutureTask.run(FutureTask.java:138)
	at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.access$301(ScheduledThreadPoolExecutor.java:98)
	at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:206)
	at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:895)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:918)
	at java.lang.Thread.run(Thread.java:662)
	at org.jboss.threads.JBossThread.run(JBossThread.java:122)

Resolution

If you need to include a very large number of static content files, consider using a web overlay.

In WEB-INF/jboss-web.xml

<jboss-web version="7.0" 
        xmlns:jboss="http://www.jboss.com/xml/ns/javaee" 
        xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
        xsi:schemaLocation="http://www.jboss.com/xml/ns/javaee jboss-web_7_0.xsd">
    ...
    <overlay>/path/to/contents/</overlay>
    ...
</jboss-web>

Root Cause

For exploded deployments, JBoss computes the "deployment timestamp" as the newest modification time of any file under the deployment directory. This requires recursively scanning that directory.

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