The Instance Listener is a special component of UniK that bootstraps UniK unikernel instances running on certain providers (currently vSphere and Virtualbox).
The instance listener is a virtual appliance that is meant to run continuously on the provider you are using. If UniK detects configuration for one of the providers that requires use of the instance listener in your daemon-config.yaml, it will attempt to automatically deploy and boot the instance listener on that infrastructure when you launch the daemon.
There is no additional configuration necessary to deploy the instance listener. UniK automatically compiles and deploys the instance listener as a unikernel.
The code for the instance listener can be found here.
UniK Instances depend on the instance listener for bootstrapping information when they boot. If your instances are not booting properly, check that the Instance Listener is alive and responding to requests on port 3000. If the instance listener fails to respond, you can restart it. Or, simply restart the daemon, and UniK will automatically re-deploy the instance listener.