Today I found a problem in our Jenkins instance. the build is failing, I checked the log on jenkins master and found the following:
12:11:18 java.net.ProtocolException: Expected HTTP 101 response but was '500 Internal Server Error' 12:11:18 at okhttp3.internal.ws.RealWebSocket.checkResponse(RealWebSocket.java:219) 12:11:18 at okhttp3.internal.ws.RealWebSocket$2.onResponse(RealWebSocket.java:186) 12:11:18 at okhttp3.RealCall$AsyncCall.execute(RealCall.java:153) 12:11:18 at okhttp3.internal.NamedRunnable.run(NamedRunnable.java:32) 12:11:18 at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149) 12:11:18 at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) 12:11:18 at java.lang.Thread.run(Thread.java:748)
It looks like jenkins agent is not able to talk to jenkins master. so agent thur out a 500 error. After the investigation I found out that was due to the network policy that my colleague was testing.
During the troubleshooting, I found someone else had the same problem. and Jenkins official answers this supposed to be a kubernetes issue rather than jenkins. So this also explains.
