Unable to run simple parallel test with appium using selenium grid

从报告中的 AppiumGridDemo.java 堆栈帧里的 test1 方法开始，重点检查 RemoteWebDriver 到 localhost:4444/wd/hub 的连接。收集 issue 中要求的完整 Appium 日志，并将其与 Selenium Grid 和 TestNG 的设置进行比较。完成的标准是找出 unknown session 错误的可复现原因，并记录可正常工作的配置或修复方案。

The problem

I am running a simple demo test to test out parallel testing with appium, selenium grid and testNG. I am getting a session not known error.

Environment

Appium 6.1.0
selenium-server and selenium-java - 3.141.59
testng - 7.4.0

Details

My test is as follows:

`@Test
	public void test1() {
		DesiredCapabilities caps = new DesiredCapabilities();
		try {
			System.out.println("Execution started");
		 	caps.setCapability("platformName", "Android");
			caps.setCapability("deviceName", "R52N20ABC");
			caps.setCapability("platformVersion", "10.0");
			caps.setCapability("udid", "R52N20ABC");
			caps.setCapability("appPackage", "CP.Android");
			caps.setCapability("automationName", "uiautomator2");
			caps.setCapability("appActivity", "crc69e3927.ActivityLicenseBrowse");	
			caps.setCapability("noReset", true);
			caps.setCapability("systemPort", "8201");
			
	
			WebDriver driver = new RemoteWebDriver(new URL("http://localhost:4444/wd/hub"), caps);
			System.out.println("Execution ended");
		} catch (MalformedURLException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
			
	}`

The following error is seen:

[RemoteTestNG] detected TestNG version 7.4.0
Execution started
FAILED: test1
org.openqa.selenium.NoSuchSessionException: The session identified by 31d74ed5-d2a5-4d63-a758-723062cac718 is not known
Build info: version: '3.141.59', revision: 'e82be7d358', time: '2018-11-14T08:17:03'
System info: host: 'PF2JP03M', ip: '192.168.137.1', os.name: 'Windows 10', os.arch: 'amd64', os.version: '10.0', java.version: '1.8.0_261'
Driver info: driver.version: RemoteWebDriver
remote stacktrace: io.appium.uiautomator2.common.exceptions.NoSuchDriverException: The session identified by 31d74ed5-d2a5-4d63-a758-723062cac718 is not known
	at io.appium.uiautomator2.handler.request.SafeRequestHandler.handle(SafeRequestHandler.java:54)
	at io.appium.uiautomator2.server.AppiumServlet.handleRequest(AppiumServlet.java:264)
	at io.appium.uiautomator2.server.AppiumServlet.handleHttpRequest(AppiumServlet.java:258)
	at io.appium.uiautomator2.http.ServerHandler.channelRead(ServerHandler.java:68)
	at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:366)
	at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:352)
	at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:345)
	at io.netty.handler.codec.MessageToMessageDecoder.channelRead(MessageToMessageDecoder.java:102)
	at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:366)
	at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:352)
	at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:345)
	at io.netty.channel.CombinedChannelDuplexHandler$DelegatingChannelHandlerContext.fireChannelRead(CombinedChannelDuplexHandler.java:435)
	at io.netty.handler.codec.ByteToMessageDecoder.fireChannelRead(ByteToMessageDecoder.java:293)
	at io.netty.handler.codec.ByteToMessageDecoder.channelRead(ByteToMessageDecoder.java:267)
	at io.netty.channel.CombinedChannelDuplexHandler.channelRead(CombinedChannelDuplexHandler.java:250)
	at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:366)
	at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:352)
	at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:345)
	at io.netty.handler.timeout.IdleStateHandler.channelRead(IdleStateHandler.java:266)
	at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:366)
	at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:352)
	at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:345)
	at io.netty.channel.DefaultChannelPipeline$HeadContext.channelRead(DefaultChannelPipeline.java:1294)
	at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:366)
	at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:352)
	at io.netty.channel.DefaultChannelPipeline.fireChannelRead(DefaultChannelPipeline.java:911)
	at io.netty.channel.nio.AbstractNioByteChannel$NioByteUnsafe.read(AbstractNioByteChannel.java:131)
	at io.netty.channel.nio.NioEventLoop.processSelectedKey(NioEventLoop.java:611)
	at io.netty.channel.nio.NioEventLoop.processSelectedKeysOptimized(NioEventLoop.java:552)
	at io.netty.channel.nio.NioEventLoop.processSelectedKeys(NioEventLoop.java:466)
	at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:438)
	at io.netty.util.concurrent.SingleThreadEventExecutor$2.run(SingleThreadEventExecutor.java:140)
	at io.netty.util.concurrent.DefaultThreadFactory$DefaultRunnableDecorator.run(DefaultThreadFactory.java:144)
	at java.lang.Thread.run(Thread.java:919)

	at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
	at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
	at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
	at java.lang.reflect.Constructor.newInstance(Constructor.java:423)
	at org.openqa.selenium.remote.W3CHandshakeResponse.lambda$errorHandler$0(W3CHandshakeResponse.java:62)
	at org.openqa.selenium.remote.HandshakeResponse.lambda$getResponseFunction$0(HandshakeResponse.java:30)
	at org.openqa.selenium.remote.ProtocolHandshake.lambda$createSession$0(ProtocolHandshake.java:126)
	at java.util.stream.ReferencePipeline$3$1.accept(ReferencePipeline.java:193)
	at java.util.Spliterators$ArraySpliterator.tryAdvance(Spliterators.java:958)
	at java.util.stream.ReferencePipeline.forEachWithCancel(ReferencePipeline.java:126)
	at java.util.stream.AbstractPipeline.copyIntoWithCancel(AbstractPipeline.java:499)
	at java.util.stream.AbstractPipeline.copyInto(AbstractPipeline.java:486)
	at java.util.stream.AbstractPipeline.wrapAndCopyInto(AbstractPipeline.java:472)
	at java.util.stream.FindOps$FindOp.evaluateSequential(FindOps.java:152)
	at java.util.stream.AbstractPipeline.evaluate(AbstractPipeline.java:234)
	at java.util.stream.ReferencePipeline.findFirst(ReferencePipeline.java:464)
	at org.openqa.selenium.remote.ProtocolHandshake.createSession(ProtocolHandshake.java:128)
	at org.openqa.selenium.remote.ProtocolHandshake.createSession(ProtocolHandshake.java:74)
	at org.openqa.selenium.remote.HttpCommandExecutor.execute(HttpCommandExecutor.java:136)
	at org.openqa.selenium.remote.RemoteWebDriver.execute(RemoteWebDriver.java:552)
	at org.openqa.selenium.remote.RemoteWebDriver.startSession(RemoteWebDriver.java:213)
	at org.openqa.selenium.remote.RemoteWebDriver.<init>(RemoteWebDriver.java:131)
	at org.openqa.selenium.remote.RemoteWebDriver.<init>(RemoteWebDriver.java:144)
	at SeleniumGridDemo.sel.com.test.grid.AppiumGridDemo.test1(AppiumGridDemo.java:28)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:498)
	at org.testng.internal.MethodInvocationHelper.invokeMethod(MethodInvocationHelper.java:133)
	at org.testng.internal.TestInvoker.invokeMethod(TestInvoker.java:598)
	at org.testng.internal.TestInvoker.invokeTestMethod(TestInvoker.java:173)
	at org.testng.internal.MethodRunner.runInSequence(MethodRunner.java:46)
	at org.testng.internal.TestInvoker$MethodInvocationAgent.invoke(TestInvoker.java:824)
	at org.testng.internal.TestInvoker.invokeTestMethods(TestInvoker.java:146)
	at org.testng.internal.TestMethodWorker.invokeTestMethods(TestMethodWorker.java:146)
	at org.testng.internal.TestMethodWorker.run(TestMethodWorker.java:128)
	at java.util.ArrayList.forEach(ArrayList.java:1259)
	at org.testng.TestRunner.privateRun(TestRunner.java:794)
	at org.testng.TestRunner.run(TestRunner.java:596)
	at org.testng.SuiteRunner.runTest(SuiteRunner.java:377)
	at org.testng.SuiteRunner.runSequentially(SuiteRunner.java:371)
	at org.testng.SuiteRunner.privateRun(SuiteRunner.java:332)
	at org.testng.SuiteRunner.run(SuiteRunner.java:276)
	at org.testng.SuiteRunnerWorker.runSuite(SuiteRunnerWorker.java:53)
	at org.testng.SuiteRunnerWorker.run(SuiteRunnerWorker.java:96)
	at org.testng.TestNG.runSuitesSequentially(TestNG.java:1212)
	at org.testng.TestNG.runSuitesLocally(TestNG.java:1134)
	at org.testng.TestNG.runSuites(TestNG.java:1063)
	at org.testng.TestNG.run(TestNG.java:1031)
	at org.testng.remote.AbstractRemoteTestNG.run(AbstractRemoteTestNG.java:115)
	at org.testng.remote.RemoteTestNG.initAndRun(RemoteTestNG.java:251)
	at org.testng.remote.RemoteTestNG.main(RemoteTestNG.java:77)


===============================================
    Default test
    Tests run: 1, Failures: 1, Skips: 0
===============================================`

```
## Link to Appium logs

Create a [GIST](https://gist.github.com) which is a paste of your _full_ Appium logs, and link them here.
Do _NOT_ paste your full Appium logs here, as it will make this issue very long and hard to read!
If you are reporting a bug, _always_ include Appium logs!


## Code To Reproduce Issue [ Good To Have ]

Please remember that with sample code it's easier to reproduce the bug and it's much faster to fix it.

Please git clone https://github.com/appium/appium and from the `sample-code` directory, use one of your favorite languages and sample apps to reproduce the issue.

In case a similar scenario is missing in sample-code, please submit a PR with one of the sample apps provided.



What does the error mean and how do i fix it?