Jenkins build agent appears offline but agent service is up and Running

Question

I am having trouble that Jenkins home page shows the Build agent is offline. But when I actually log in to build agent server, the agent service is up and running.

I am using Windows 2003 OS for all my Build agent and controller server. The only way to get it online is to restart the service again.

Kinross

After restarting the master node our problem gone away. – Particularly

Answer 1

Follow the given steps, you will not required to restart the services.

Goto Jenkins -> Manage Jenkins -> Manage Nodes

This will show you the list configured nodes. In which

Build Slave -> Launch Slave Agent (Where "Build Slave" is your slave node.)

This will work if your slave is configured properly and connected with the services.

Spend

Hi Kishan, Thanks for the help. I wonder why this is happening do you have guess where i can find the reason for this. I think if the slave is up and running Master should not show it is off line. – Kinross

@Kinross Master Jenkins server constantly checks for the slave or other configured node connections in background. you can find the connection problem in log of nodes. for example your node is Demo_Slave than you can view this log at Jenkins -> Nodes -> Demo_Slave -> Log. you will find reason in that log. – Spend

I'm having the exact same issue: JNLP slave agent is launched and shows connected state, but jenkins server shows slave as offline. The only entry in the slave log is JNLP agent connected from /10.0.0.134 and the spinning icon. The only thing that helped the last time is the restart of jenkins/apache. – Jitterbug

Update: I upgraded to 1.561 and the issue seems to be fixed (for now). I'll keep an eye on it nevertheless... – Jitterbug

I have 1.571 running and the same issue. The server logs also the accepted connection but the ui still tells me that the slave is offline... – Fluctuate

Same problem with a Jenkins 1.629, and suggested actions do not change anything. – Osteopathy

Answer 2

Jenkins master need communicate with Slave with ssh connection if master and slave are not in the same node. Double check if master's ssh public key is in slave's ~/.ssh/authorized_keys.

Detrude

Answer 3

If you don't have the rights, to open the "Manage Jenkins" settings page, an alternative way to reload an node is:

Dashboard -> "Build Executor Status" -> choose offline agent -> status -> check the buttons on top right

Fenner