Listener port of a VS disappears from netstat and log shows "Error doing destroy"

Products

• Service Virtualization

Issue/Introduction

Occasionally the VS listener is going down. Services on the Portal console show that the VS is up and running.
But netstat does not show the port as listening. Restarting all the DevTest services resolves the issue and netstat shows the port as listening again.

The following error is shown in the log: 
2022-07-12 03:01:22,758Z (13:01) [SVC469v4 [VS_SVC469v4_Run]/1] INFO  com.itko.lisa.test.TestCase    - Error doing destroy() on Step Virtual HTTPS Listener: null
java.lang.NullPointerException
        at com.itko.lisa.vse.stateful.protocol.http.HttpListenStep.shutdown(HttpListenStep.java:677)
        at com.itko.lisa.vse.stateful.protocol.http.HttpListenStep.destroy(HttpListenStep.java:645)
        at com.itko.lisa.test.TestCase.destroy(TestCase.java:1068)
        at com.itko.lisa.test.TestExec.endTest(TestExec.java:1154)
        at com.itko.lisa.test.NormalEnd.execute(NormalEnd.java:122)
        at com.itko.lisa.test.TestNode.executeNode(TestNode.java:995)
        at com.itko.lisa.test.TestCase.execute(TestCase.java:1297)
        at com.itko.lisa.test.TestCase.execute(TestCase.java:1198)
        at com.itko.lisa.test.TestCase.executeNextNode(TestCase.java:1183)
        at com.itko.lisa.test.TestCase.executeTest(TestCase.java:1124)
        at com.itko.lisa.coordinator.Instance.run(Instance.java:208)

Environment

Release : 10.6, 10.7

Component : DevTest Virtual Service

Resolution

The error has been reported for environments that are running a "security scan" on the listen port of the VS.
Also when running out of disk space, the error has been observed.

This error can be resolved by restarting the VSE or redeploying the VS.
To avoid the error in the first place, do not run the port scanner on the Listen ports of the Virtual Services.