Error Message "netty.exception.LocalTransportException" Is Reported During Flink Task Running
Symptom
The error message "netty.exception.LocalTransportException" is displayed during Flink task running.
Cause Analysis
Network jitter or packet loss occurs. The timeout occurs when the following task communicates with the upstream and downstream operators through Netty. During the communication, Flink tasks communicate with each other through the socket at the JDK bottom layer, and the socket reads and writes only invoke the interface at the OS bottom layer. After the timeout, "IO EXCEPTION" or "LocalTransPortException" is reported.
Generally, the root cause is network faults, including:
- Network jitter or packet loss
- Insufficient network bandwidth
- Abnormal network between data nodes
In addition, the open-source community also provides some scenarios where this error is reported:
Procedure
If the fault occurs only once half a year or once a year, ignore it. If the fault occurs frequently, you are advised to check network logs and enable the automatic restart. For example, set restart-strategy to failure-rate in the flink-conf.xml file.
