Ensure that you have enabled the serial console on the cloud controller where the nova-serialproxy service is running before you enable the serial console on the compute node.
These steps are performed by default when you run the setup.sh script except for the value of the enabled keyword, which you must set manually.
IP-address is the IP address of the cloud controller.
[serial_console] serialproxy_host=IP-address serialproxy_port=6083 enabled=true base_url=ws://IP-address:6083/ listen=$my_ip proxyclient_address=$my_ip
nova# svcadm restart nova-compute