Comment 1 for bug 993666

To get a better sense of what was going on, I added a "read" at several places to pause the ./stack.sh script.

With the first one, I hit the jackpot:

+ add_nova_opt rabbit_password=0a88a309651cf87fedee
+ echo rabbit_password=0a88a309651cf87fedee
+ add_nova_opt glance_api_servers=10.0.2.15:9292
+ echo glance_api_servers=10.0.2.15:9292
+ add_nova_opt force_dhcp_release=True
+ echo force_dhcp_release=True
+ '[' -n '' ']'
+ '[' False '!=' False ']'
+ '[' False '!=' False ']'
+ '[' True '!=' True ']'
+ [[ -z '' ]]
+ [[ -n '' ]]

The read stopped the script right after 'force_dhcp_release' and before the XenServer checks.

From that point (with the script "paused"), I was able to restart the network and then resume the script, resulting in a complete, error-free install.