javax.websocket.DeploymentException: Handshake response not received.
at org.glassfish.tyrus.client.ClientManager$3$1.run(ClientManager.java:694)
at org.glassfish.tyrus.client.ClientManager$3.run(ClientManager.java:712)
...
at org.glassfish.tyrus.client.ClientManager$SameThreadExecutorService.execute(ClientManager.java:866)
at java.base/java.util.concurrent.AbstractExecutorService.submit(AbstractExecutorService.java:118)
at org.glassfish.tyrus.client.ClientManager.connectToServer(ClientManager.java:511)
at org.glassfish.tyrus.client.ClientManager.connectToServer(ClientManager.java:355)
at hudson.cli.CLI.webSocketConnection(CLI.java:323)
at hudson.cli.CLI._main(CLI.java:301)
at hudson.cli.CLI.main(CLI.java:95)
Testing CLI, agent connections with the new '-websocket' functionality added by [ JEP-222|[https://github.com/jenkinsci/jep/blob/master/jep/222/README.adoc]].
javax.websocket.DeploymentException: Handshake response not received. at org.glassfish.tyrus.client.ClientManager$3$1.run(ClientManager.java:694) at org.glassfish.tyrus.client.ClientManager$3.run(ClientManager.java:712) ... at org.glassfish.tyrus.client.ClientManager$SameThreadExecutorService.execute(ClientManager.java:866) at java.base/java.util.concurrent.AbstractExecutorService.submit(AbstractExecutorService.java:118) at org.glassfish.tyrus.client.ClientManager.connectToServer(ClientManager.java:511) at org.glassfish.tyrus.client.ClientManager.connectToServer(ClientManager.java:355) at hudson.cli.CLI.webSocketConnection(CLI.java:323) at hudson.cli.CLI._main(CLI.java:301) at hudson.cli.CLI.main(CLI.java:95)
Jetty access log shows: {code:java} 172.18.0.3 - - [25/Feb/2020:01:48:06 +0000] "GET /cli/ws HTTP/1.1" 101 0 "-" "-" {code} CLI output: {code:java} javax.websocket.DeploymentException: Handshake response not received. at org.glassfish.tyrus.client.ClientManager$3$1.run(ClientManager.java:694) at org.glassfish.tyrus.client.ClientManager$3.run(ClientManager.java:712) ... at org.glassfish.tyrus.client.ClientManager$SameThreadExecutorService.execute(ClientManager.java:866) at java.base/java.util.concurrent.AbstractExecutorService.submit(AbstractExecutorService.java:118) at org.glassfish.tyrus.client.ClientManager.connectToServer(ClientManager.java:511) at org.glassfish.tyrus.client.ClientManager.connectToServer(ClientManager.java:355) at hudson.cli.CLI.webSocketConnection(CLI.java:323) at hudson.cli.CLI._main(CLI.java:301) at hudson.cli.CLI.main(CLI.java:95) {code} When I attach a debugger to the Jenkins server it seems to get stuck here: [https://github.com/jenkinsci/jenkins/blob/master/core/src/main/java/hudson/cli/CLIAction.java#L255]