Today, I got this error in VIRL:

Error Launching Simulation.

  java.lang.IllegalStateException: Already connected

I hadn’t done anything unusual. I created a new topology file, added a single device, and started the simulation. Then the error popped up.

I remembered that the server guys had shut down a few servers recently, as they had to install a new UPS. Could ‘Already Connected’ be a misleading error? Maybe VIRL got a new IP from DHCP, or perhaps the VM hadn’t started?

As a quick test, I went to File -> Preferences, then clicked on the Node Subtypes tab. Down the bottom fo the page I clicked Fetch from server.

The result was this error:

Check the URL and availability of the web services

Connection timed out: connect

A ping to the IP of the VIRL server confirmed that there was no response.

In my case, it turns out that the host server was stuck at the boot screen. One of the server guys fixed this and started the VIRL VM. Everything started working.

This error is quite misleading. As it turns out, Already Connected really means Server or Service is Unavailable