Remote Debugging in Nova
You can use a remote debugger to attach to nova services by specifying the host and port as command line arguments. For example
/usr/local/bin/nova-compute --config-file /etc/nova/nova.conf --remote_debug-host 172.16.245.1 --remote_debug-port 1234
In order to do this you need to have a remote debug server - this wiki describes how to use remote debugging with pycharm. You need a commercial license to do remote debugging with pycharm.
Preparing the server
Start pycharm and create a remote debug runtime configuration
Preparing the client
First you need to copy the pydev client script to the environment where you are running nova services.