jenkins port:50001 is not reacha

问题：使用Jenkins 搭建node（slave）时，报以下错误

java.io.IOException: https://jenkins-api.bj2.agoralab.co/ provided port:50001 is not reachable
at org.jenkinsci.remoting.engine.JnlpAgentEndpointResolver.resolve(JnlpAgentEndpointResolver.java:314)
at hudson.remoting.Engine.innerRun(Engine.java:694)
at hudson.remoting.Engine.run(Engine.java:519)

原因：jenkins 默认已启用websocket，但仍留有jnlp，导致通信失败；

解决办法：在node设置中，选择 “Use websocket”