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Warning of "Unknown-Agent null@null"

yohnishi
Organizer

Hi,

We are currently investigating the Agent's failure. The following warning has been output to the Collector's log once.

There is no misconfiguration in the settings, but why was the log output as "Unknown -Agent" Agent name? ("Unknown-Agent null@null" is the same in the log output.)

Since the timing is when the host was restarted, I think it is a temporary log that the connection process failed temporarily.

Is my understanding correct?

2020-mm-dd HH:MM:SS UTC WARNING [AgentListener] Unable to create connection for request Unknown-Agent null@null:0 7.2.4.1039 requested service: LoadBalancing. Another thread is currently creating such a connection!
StackTrace of [tid=722, AgentListenerServiceFactory-Thread-36]
              at java.lang.String.intern(Native Method)
              at com.dynatrace.diagnostics.core.serialization.serializer.ClassInheritanceSerializer35.deserialize(ClassInheritanceSerializer35.java:43)
              at com.dynatrace.diagnostics.core.serialization.serializer.ClassInheritanceSerializer35.deserialize(ClassInheritanceSerializer35.java:19)
              at com.dynatrace.diagnostics.core.serialization.abstracts.DefaultSerializer.deserialize(DefaultSerializer.java:69)
              at com.dynatrace.diagnostics.core.serialization.abstracts.DefaultSerializer.deserialize(DefaultSerializer.java:27)
              at com.dynatrace.diagnostics.core.serialization.abstracts.AbstractEmitterResolverCache.resolveCachedObject(AbstractEmitterResolverCache.java:287)
              at com.dynatrace.diagnostics.core.serialization.abstracts.AbstractEmitterResolverCache.resolveCachedObject(AbstractEmitterResolverCache.java:178)
              at com.dynatrace.diagnostics.core.serialization.abstracts.CommonCachedSerializers.resolveClassInheritance(CommonCachedSerializers.java:1918)
              at com.dynatrace.diagnostics.core.serialization.serializer.ClassInheritanceSerializer35.deserialize(ClassInheritanceSerializer35.java:48)
              at com.dynatrace.diagnostics.core.serialization.serializer.ClassInheritanceSerializer35.deserialize(ClassInheritanceSerializer35.java:19)
              at com.dynatrace.diagnostics.core.serialization.abstracts.DefaultSerializer.deserialize(DefaultSerializer.java:69)
              at com.dynatrace.diagnostics.core.serialization.abstracts.DefaultSerializer.deserialize(DefaultSerializer.java:27)
              at com.dynatrace.diagnostics.core.serialization.abstracts.AbstractEmitterResolverCache.resolveCachedObject(AbstractEmitterResolverCache.java:287)
              at com.dynatrace.diagnostics.core.serialization.abstracts.AbstractEmitterResolverCache.resolveCachedObject(AbstractEmitterResolverCache.java:178)
              at com.dynatrace.diagnostics.core.serialization.abstracts.CommonCachedSerializers.resolveClassInheritance(CommonCachedSerializers.java:1918)
              at com.dynatrace.diagnostics.core.serialization.serializer.InheritanceMapSerializer30.deserialize(InheritanceMapSerializer30.java:48)
              at com.dynatrace.diagnostics.core.serialization.serializer.InheritanceMapSerializer30.deserialize(InheritanceMapSerializer30.java:24)
              at com.dynatrace.diagnostics.core.serialization.SerializationManager.deserializeObject(SerializationManager.java:637)
              at com.dynatrace.diagnostics.collector.shared.inheritance.InheritanceMapStorage.readInheritanceMap(InheritanceMapStorage.java:380)
              at com.dynatrace.diagnostics.collector.agentcenter.InheritanceMapManager.startInheritanceMapUsage(InheritanceMapManager.java:154)
              at com.dynatrace.diagnostics.collector.agentcenter.InheritanceMapManager.startInheritanceMapUsage(InheritanceMapManager.java:121)
              at com.dynatrace.diagnostics.collector.agentcenter.AgentPeer.initInheritanceMap(AgentPeer.java:2963)
              at com.dynatrace.diagnostics.collector.agentcenter.AgentPeer.applyRules(AgentPeer.java:799)
              at com.dynatrace.diagnostics.collector.agentcenter.AgentCenter.applyProfileChanges(AgentCenter.java:1222)
              at com.dynatrace.diagnostics.collector.agentcenter.AgentCenter.activateAgentSettings(AgentCenter.java:1157)
              at com.dynatrace.diagnostics.collector.agentcenter.AgentCenter.activateAgentSettings(AgentCenter.java:1112)
              at com.dynatrace.diagnostics.collector.agentcenter.AgentListener.createAgent(AgentListener.java:310)
              at com.dynatrace.diagnostics.collector.agentcenter.AgentListener.access$1100(AgentListener.java:110)
              at com.dynatrace.diagnostics.collector.agentcenter.AgentListener$ConnectionHandler.processInstrumentationRequest(AgentListener.java:875)
              at com.dynatrace.diagnostics.collector.agentcenter.AgentListener$ConnectionHandler.run(AgentListener.java:573)
              at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
              at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
              at java.lang.Thread.run(Thread.java:748)



2020-mm-dd HH:MM:SS UTC INFO [AgentPeer] AgentName@server:30438 (Java, v7.2.4.1039, id=177f6371, profile=ProfileName, conf=Default, group=GroupName, starttime='Fri mmm dd HH:MM:DD JST 2020 (local time on Agent: 2020-mm-dd HH:MM:SS UTC)')


1 REPLY 1

Joe_Hoffman
Dynatrace Champion
Dynatrace Champion

This situation could happen when an agent is connecting and there is a collision as to which collector thread is going to handle the agent connection request. Normally this does not happen, but a strange timing issue has been detected. Notice the message at the top of the log, "Another thread is currently creating such a connection!" This tells me that the agent connection request is being handled by a different thread so this thread abandoned the handling and didn't know the agent name@host data.

Check to verify the agent is connected in Agent Overview. If not, restart the monitored process.

If this problem continues to happen, I would open a support case, but I suspect it is a one-time event.