Troubleshooting the sensor

This topic describes common problems that occur with the Ping sensor and presents solutions for those problems.

Ping sensor discovery ends with an unable to establish loopback connection message

Problem
The sensor fails when the scope of discovery is large, due to a timeout error, and the following message is displayed:
Unable to establish loopback connection
View the log file for a detailed description of the message, for example:
<log start>
java.io.IOException: Unable to establish loopback connection
at sun.nio.ch.PipeImpl$Initializer.run(PipeImpl.java:172)
at java.security.AccessController.doPrivileged(AccessController.java:246)
at sun.nio.ch.PipeImpl.<init>(PipeImpl.java:188)
at sun.nio.ch.SelectorProviderImpl.openPipe(SelectorProviderImpl.java:45)
at java.nio.channels.Pipe.open(Pipe.java:148)
at sun.nio.ch.WindowsSelectorImpl.<init>(WindowsSelectorImpl.java:192)
at sun.nio.ch.WindowsSelectorProvider.openSelector(WindowsSelectorProvider.java:53)
at java.nio.channels.Selector.open(Selector.java:224)
at com.collation.platform.session.Ping$Connector.<init>(Ping.java:303)
at com.collation.platform.session.Ping.pingArray(Ping.java:656)
at com.collation.platform.session.Ping.pingLoop(Ping.java:574)
at com.collation.platform.session.Ping.ping(Ping.java:557)
at com.ibm.cdb.discover.sensor.net.ping.PingSensor.do_ping(PingSensor.java:75)
at com.ibm.cdb.discover.sensor.net.ping.PingSensor.discover(PingSensor.java:92)
at com.collation.discover.engine.AgentRunner.run(AgentRunner.java:214)
at com.collation.discover.engine.DiscoverEngine.processWorkItem(DiscoverEngine.java:1184)
at com.collation.discover.engine.DiscoverEngine$DiscoverWorker.run(DiscoverEngine.java:867)
Caused by: java.nio.channels.ClosedByInterruptException
at java.nio.channels.spi.AbstractInterruptibleChannel.end(AbstractInterruptibleChannel.java:216)
at sun.nio.ch.SocketChannelImpl.connect(SocketChannelImpl.java:543)
at java.nio.channels.SocketChannel.open(SocketChannel.java:161)
at sun.nio.ch.PipeImpl$Initializer.run(PipeImpl.java:120)
... 16 more
<log end>
Solution
Use one of the following methods to resolve the problems:
  • Perform the discovery on a smaller scope.
  • In the collation.properties file, increase the timeout value for a longer discover time for the following property:
    com.collation.discover.agent.PingSensor.timeout=600000 

Ping sensor discovery ends with error CTJTD0510E

Problem
If you enable the ping discovery over UDP, it is possible that, when discovering large scopes, the sensor ends with the following error because it exceeds the limit of open sockets:
CTJTD0510E The following error occurred in the ping sensor: Too many open files.
View the log file for a detailed description of the message, for example:
<log start>
sensor.PingSensor - Exception in Ping Broadcast Agent
java.io.IOException: Too many open files
    at sun.nio.ch.IOUtil.makePipe(Native Method)
		at sun.nio.ch.EPollSelectorImpl.<init>(EPollSelectorImpl.java:77)
    at sun.nio.ch.EPollSelectorProvider.openSelector(EPollSelectorProvider.java:48)
    at java.nio.channels.Selector.open(Selector.java:238)
    at com.collation.platform.session.Ping$TcpConnector.<init>(Ping.java:354)
    at com.collation.platform.session.Ping$TcpConnector.<init>(Ping.java:349)
    at com.collation.platform.session.Ping.pingArray(Ping.java:926)
    at com.collation.platform.session.Ping.pingLoop(Ping.java:840)
    at com.collation.platform.session.Ping.ping(Ping.java:821)
    at com.ibm.cdb.discover.net.ping.sensor.PingSensor.do_ping(PingSensor.java:81)
    at com.ibm.cdb.discover.net.ping.sensor.PingSensor.discover(PingSensor.java:114)
    at com.collation.discover.engine.AgentRunner.doRegularDiscovery(AgentRunner.java:349)
    at com.collation.discover.engine.AgentRunner.run(AgentRunner.java:271)
    at com.collation.discover.engine.DiscoverEngine.processWorkItem(DiscoverEngine.java:736)
    at com.collation.discover.engine.worker.DiscoverWorker.processWorkItemWithMetrics(DiscoverWorker.java:100)
    at com.collation.discover.engine.worker.DiscoverWorker.run(DiscoverWorker.java:146)
2012-09-12 16:48:29,076 DiscoverManager [DiscoverWorker-5] 
PingSensor-9.156.46.6˜9.156.46.254 WARN engine.AgentRunner - 
[AgentRunner.W.1] AgentException thrown in agent
com.collation.discover.agent.AgentException: 
CTJTD0510E The following error occurred in the ping sensor: Too many open files .
<log end>
Solution
Use one of the following methods to resolve the problems:
  • Perform the discovery on a smaller scope.
  • On UNIX systems, increase the open file limit on the discovery server. For more information about the open file limit, see TADDM server software requirements.

Ping sensor fails with a timeout error

Problem
For large scopes, the sensor fails with a timeout error.
All the actions of the Ping sensor that are visible in UI are run in a sequence. The timeout value that is specified in the collation.properties file defines the total time that is needed to finish those actions.
Solution
Use one of the following methods to resolve the problems:
  • Perform the discovery on a smaller scope.
  • In the collation.properties file, increase the timeout value for a longer discover time for the following property:
    com.collation.discover.agent.PingSensor.timeout=600000 

The sensor does not discover endpoints over the UDP protocol

Problem
When discovering endpoints that are accessible only over the UDP protocol, some of them are missing.
Solution
You must configure the properties that are responsible for the discovery over the UDP protocol. For more information about those properties, see Configuring the collation.properties file.
To retrieve information about open UDP ports, the Ping sensor uses the SNMP protocol to query the discovery endpoints. Make sure that the proper SNMP or SNMPv3 authentication credentials are provided in the TADDM access list. You can also verify if your firewall passes the network traffic through the ports that are specified in the com.ibm.cdb.discover.pingUDPPorts property.