Hint: the cause is in missing egg-info. Compare:
Ubuntu (broken): root@node-2:~# ls -al /usr/lib/python2.7/dist-packages/ | grep horizon drwxr-xr-x 16 root root 4096 Apr 3 09:34 horizon
CentOS (working): [root@node-1 ~]# ls -al /usr/lib/python2.6/site-packages/ | grep horizon drwxr-xr-x 16 root root 4096 Apr 3 09:52 horizon drwxr-xr-x 2 root root 4096 Apr 3 09:52 horizon-2014.2.2-py2.6.egg-info
Hint: the cause is in missing egg-info. Compare:
Ubuntu (broken): python2. 7/dist- packages/ | grep horizon
root@node-2:~# ls -al /usr/lib/
drwxr-xr-x 16 root root 4096 Apr 3 09:34 horizon
CentOS (working): python2. 6/site- packages/ | grep horizon 2014.2. 2-py2.6. egg-info
[root@node-1 ~]# ls -al /usr/lib/
drwxr-xr-x 16 root root 4096 Apr 3 09:52 horizon
drwxr-xr-x 2 root root 4096 Apr 3 09:52 horizon-