How to Debug OpenStack DevStack

1)
How to enable logging in OpenStack via devstack

Define the following variable in ~/devstack/localrc and run ./unstack and ./stack.

###To capture the screen output of OpenStack services in separate log files
SCREEN_LOGDIR=/home/saju/openstack/screen_dir

###To capture the output of ./stack in one log file
LOGFILE=/opt/stack/logs/stack.sh.log
VERBOSE=True

2)
Search for the request id (req-*) in log files to trace the logs of a particulate request

Example of request ID:
-------------------------------------
req-8bcbe2a3-488d-461a-b9ba-d272958828ca

3)
Use
import pdb
pdb.set_trace()