[FLUME-1481] Custom component may not support dynamic configuration

• Type: Bug
• Status: Open
• Priority: Major
• Resolution: Unresolved
• Affects Version/s: 1.2.0
• Component/s: Channel, Sinks+Sources
• Assignee: Unassigned
• Reporter: Denny Ye
• Created: 13/Aug/12 02:57
• Updated: 25/Jun/13 00:12

Description

Flume NG provides more flexible extension at primary component. It's very useful for users. Each custom component should implement LifecycleAware interface in different ways.

If the startup thread blocked at 'start()' method, the component will be runs normally. Meanwhile, dynamic configuration function will be disable with unreachable 'synchronized' lock.

Example in my environment. Others also may meet this problem with custom component.

"lifecycleSupervisor-1-3" prio=10 tid=0x000000005d562000 nid=0x2a53 in Object.wait() [0x0000000042a6b000]
java.lang.Thread.State: WAITING (on object monitor)
at java.lang.Object.wait(Native Method)

• waiting on <0x00002aaacc740d30> (a org.apache.thrift.server.TNonblockingServer$SelectThread)
  at java.lang.Thread.join(Thread.java:1143)
• locked <0x00002aaacc740d30> (a org.apache.thrift.server.TNonblockingServer$SelectThread)
  at java.lang.Thread.join(Thread.java:1196)
  at org.apache.thrift.server.TNonblockingServer.joinSelector(TNonblockingServer.java:170)
  at org.apache.thrift.server.TNonblockingServer.serve(TNonblockingServer.java:114)
  at org.apache.flume.source.scribe.ScribeSource.start(ScribeSource.java:88)
  at org.apache.flume.source.EventDrivenSourceRunner.start(EventDrivenSourceRunner.java:44)
  at org.apache.flume.lifecycle.LifecycleSupervisor$MonitorRunnable.run(LifecycleSupervisor.java:237)
• locked <0x00002aaacc755d78> (a org.apache.flume.source.EventDrivenSourceRunner)
  at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:441)

"conf-file-poller-0" prio=10 tid=0x000000005d4de000 nid=0x2a50 waiting for monitor entry [0x0000000042869000]
java.lang.Thread.State: BLOCKED (on object monitor)
at org.apache.flume.lifecycle.LifecycleSupervisor.unsupervise(LifecycleSupervisor.java:153)

• waiting to lock <0x00002aaacc755d78> (a org.apache.flume.source.EventDrivenSourceRunner)
• locked <0x00002aaacc755c30> (a org.apache.flume.lifecycle.LifecycleSupervisor)
  at org.apache.flume.node.nodemanager.DefaultLogicalNodeManager.stopAllComponents(DefaultLogicalNodeManager.java:73)
  at org.apache.flume.conf.properties.PropertiesFileConfigurationProvider.load(PropertiesFileConfigurationProvider.java:219)
  at org.apache.flume.conf.file.AbstractFileConfigurationProvider.doLoad(AbstractFileConfigurationProvider.java:123)
• locked <0x00002aaacc75bfd0> (a org.apache.flume.conf.properties.PropertiesFileConfigurationProvider)
  at org.apache.flume.conf.file.AbstractFileConfigurationProvider.access$300(AbstractFileConfigurationProvider.java:38)
  at org.apache.flume.conf.file.AbstractFileConfigurationProvider$FileWatcherRunnable.run(AbstractFileConfigurationProvider.java:202)
  at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:441)

The former doesn't release object lock and the follower cann't obtains specified object lock. There are staying lock starvation. Dynamic configuration function cannot apply for this component.

This issue have happening only on case : component initialization thread was blocked at 'start' method.