jnlp kubernetes slave agent issue

Go to http://your_server/configureSecurity/ and chose "random" option for "Agents:TCP port for JNLP agents" That might help.

jenkins JNLP tcp port docs

Jenkins can use a TCP port to communicate with inbound (formerly knownas “JNLP”) agents, such as Windows-based agents. As of Jenkins 2.0, bydefault this port is disabled.

For administrators wishing to use inbound TCP agents, the two port options are:

1. Random: The TCP port is chosen at random to avoid collisions on the Jenkins master. The downside to randomized ports is that they are chosen during the boot of the Jenkins controller, making it difficult to manage firewall rules allowing TCP traffic.

2. Fixed: The port is chosen by the Jenkins administrator and is consistent across reboots of the Jenkins controller. This makes it easier to manage firewall rules allowing TCP-based agents to connect to the controller.

As of Jenkins 2.217, inbound agents may instead be configured to useWebSocket transport to connect to Jenkins. In this case no extra TCPport need be enabled and no special security configuration is needed.

Related questions:

1. Jenkins Kubernetes plugin failing to provision jnlp-slave pods

2. Kubernetes - Jenkins slaves are offline