如何解决启动代理时出现的一般“意外错误”。这可能是 Jenkins 代理启动时 Jenkins 错误中的一个错误答案

【问题标题】：How to solve generic 'Unexpected error in launching an agent. This is probably a bug in Jenkins' error on Jenkins agent startup如何解决启动代理时出现的一般“意外错误”。这可能是 Jenkins 代理启动时 Jenkins 错误中的一个错误
【发布时间】：2022-01-27 22:58:59
【问题描述】：

我已经使用以下设置配置了 docker cloud 动态代理创建：和代理配置如下：

但它们无法启动。一直在谷歌搜索，但由于我几乎没有什么可以处理日志，所以我不知道如何解决这个问题。

Connecting to docker container 2169d7b0f9de955c89916da421dc6e04f41104423d0fdcd28796162225cf491f, running command java -jar //remoting-4.11.2.jar -noReconnect -noKeepAlive -agentLog //agent.log
HTTP/1.1 101 UPGRADED
Content-Type: application/vnd.docker.raw-stream
Connection: Upgrade
Upgrade: tcp
Api-Version: 1.41
Docker-Experimental: false
Ostype: linux
Server: Docker/20.10.12 (linux)
ERROR: Unexpected error in launching an agent. This is probably a bug in Jenkins
Also:   java.lang.Throwable: launched here
    at hudson.slaves.SlaveComputer._connect(SlaveComputer.java:282)
    at hudson.model.Computer.connect(Computer.java:440)
    at hudson.slaves.SlaveComputer.doLaunchSlaveAgent(SlaveComputer.java:796)
    at java.lang.invoke.MethodHandle.invokeWithArguments(MethodHandle.java:627)
    at org.kohsuke.stapler.Function$MethodFunction.invoke(Function.java:393)
    at org.kohsuke.stapler.Function$InstanceFunction.invoke(Function.java:405)
    at org.kohsuke.stapler.interceptor.RequirePOST$Processor.invoke(RequirePOST.java:77)
    at org.kohsuke.stapler.PreInvokeInterceptedFunction.invoke(PreInvokeInterceptedFunction.java:26)
    at org.kohsuke.stapler.Function.bindAndInvoke(Function.java:208)
    at org.kohsuke.stapler.Function.bindAndInvokeAndServeResponse(Function.java:141)
    at org.kohsuke.stapler.MetaClass$11.doDispatch(MetaClass.java:536)
    at org.kohsuke.stapler.NameBasedDispatcher.dispatch(NameBasedDispatcher.java:58)

日志的最后部分停留：

java.io.EOFException: unexpected stream termination
    at hudson.remoting.ChannelBuilder.negotiate(ChannelBuilder.java:464)
    at hudson.remoting.ChannelBuilder.build(ChannelBuilder.java:409)
    at hudson.slaves.SlaveComputer.setChannel(SlaveComputer.java:432)
    at hudson.slaves.SlaveComputer.setChannel(SlaveComputer.java:399)
    at io.jenkins.docker.connector.DockerComputerAttachConnector$DockerAttachLauncher.launch(DockerComputerAttachConnector.java:321)
    at hudson.slaves.DelegatingComputerLauncher.launch(DelegatingComputerLauncher.java:63)
    at io.jenkins.docker.connector.DockerDelegatingComputerLauncher.launch(DockerDelegatingComputerLauncher.java:37)
    at hudson.slaves.SlaveComputer.lambda$_connect$0(SlaveComputer.java:293)
    at jenkins.util.ContextResettingExecutorService$2.call(ContextResettingExecutorService.java:46)
    at jenkins.security.ImpersonatingExecutorService$2.call(ImpersonatingExecutorService.java:80)
    at java.util.concurrent.FutureTask.run(FutureTask.java:266)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
    at java.lang.Thread.run(Thread.java:748)

在詹金斯日志中我看到：

96a29780b14e340c1667f2 for node Jenkins JDK11 agent-00000a8utz442 from image: jenkins/agent:alpine
2022-01-27 22:56:32.628+0000 [id=188]   INFO    i.j.d.c.DockerMultiplexedInputStream#readInternal: stderr from Jenkins JDK11 agent-00000a8utz442 (4611c8568d1b73e6a8b7e54613f7ef06c79210f03a96a29780b14e340c1667f2): Jan 27, 2022 10:56:32 PM org.jenkinsci.remoting.engine.WorkDirManager setupLogging
INFO: Using /agent.log as an agent error log destination; output log will not be generated
2022-01-27 22:56:32.628+0000 [id=188]   INFO    i.j.d.c.DockerMultiplexedInputStream#readInternal: stderr from Jenkins JDK11 agent-00000a8utz442 (4611c8568d1b73e6a8b7e54613f7ef06c79210f03a96a29780b14e340c1667f2): Exception in thread "main"
2022-01-27 22:56:32.629+0000 [id=188]   INFO    i.j.d.c.DockerMultiplexedInputStream#readInternal: stderr from Jenkins JDK11 agent-00000a8utz442 (4611c8568d1b73e6a8b7e54613f7ef06c79210f03a96a29780b14e340c1667f2): java.io.FileNotFoundException: /agent.log (Permission denied)
2022-01-27 22:56:32.629+0000 [id=188]   INFO    i.j.d.c.DockerMultiplexedInputStream#readInternal: stderr from Jenkins JDK11 agent-00000a8utz442 (4611c8568d1b73e6a8b7e54613f7ef06c79210f03a96a29780b14e340c1667f2):    at java.base/java.io.FileOutputStream.open0(Native Method)
2022-01-27 22:56:32.629+0000 [id=188]   INFO    i.j.d.c.DockerMultiplexedInputStream#readInternal: stderr from Jenkins JDK11 agent-00000a8utz442 (4611c8568d1b73e6a8b7e54613f7ef06c79210f03a96a29780b14e340c1667f2):    at java.base/java.io.FileOutputStream.open(Unknown Source)
2022-01-27 22:56:32.629+0000 [id=188]   INFO    i.j.d.c.DockerMultiplexedInputStream#readInternal: stderr from Jenkins JDK11 agent-00000a8utz442 (4611c8568d1b73e6a8b7e54613f7ef06c79210f03a96a29780b14e340c1667f2):    at java.base/java.io.FileOutputStream.<init>(Unknown Source)

实际上也没有那么多信息。

【问题讨论】：

Using /agent.log as an agent error log destination 后跟 /agent.log (Permission denied) 非常有意义。 Jenkins 正在尝试将日志文件写入根目录，这显然是行不通的。找出配置中日志文件的定义位置，并将路径修复到您的进程可以写入的位置。
启动命令显示-jar //remoting-4.11.2.jar 的事实，双斜杠表明尚未定义变量（远程 FS 根？）。嗯（检查图像）....
是的，你都说得对，根定义不正确。更新它并按预期工作。谢谢！
@PedroZuppelli 能否请您指导我需要遵循的步骤来摆脱这个问题。这对我真的很有帮助。
如答案所述，代理配置中的远程文件系统根丢失，更新它解决了问题

标签： java jenkins jenkins-pipeline

【解决方案1】：

在代理配置中，将 /home/jenkins 放在远程文件系统根字段中。我遇到了同样的问题，这为我解决了问题。

【讨论】：