[YARN-9813] RM does not start on JDK11 when UIv2 is enabled

• Type: Bug
• Status: Resolved
• Priority: Critical
• Resolution: Fixed
• Affects Version/s: 3.1.2
• Fix Version/s: 3.3.0, 3.2.1, 3.1.4
• Component/s: resourcemanager, yarn
• Target Version/s: 3.2.0, 3.3.0, 3.1.4
• Hadoop Flags: Reviewed
• Assignee: Adam Antal
• Reporter: Adam Antal
• Created: 06/Sep/19 07:30
• Updated: 09/Sep/19 08:10
• Resolved: 07/Sep/19 02:25

Description

Starting a ResourceManager on JDK11 with UIv2 is enabled, RM startup fails with the following message:

Error starting ResourceManager
java.lang.ClassCastException: class jdk.internal.loader.ClassLoaders$AppClassLoader cannot be cast to class java.net.URLClassLoader (jdk.internal.loader.ClassLoaders$AppClassLoader and java.net.URLClassLoader are in module java.base of loader 'bootstrap')
	at org.apache.hadoop.yarn.server.resourcemanager.ResourceManager.startWepApp(ResourceManager.java:1190)
	at org.apache.hadoop.yarn.server.resourcemanager.ResourceManager.serviceStart(ResourceManager.java:1333)
	at org.apache.hadoop.service.AbstractService.start(AbstractService.java:194)
	at org.apache.hadoop.yarn.server.resourcemanager.ResourceManager.main(ResourceManager.java:1531)

It is a known issue that the systemClassLoader is not URLClassLoader anymore from JDK9 (see related UT failure: YARN-9512).

Issue Links

• relates to: YARN-9512 [JDK11] TestAuxServices#testCustomizedAuxServiceClassPath fails because of ClassCastException.