Hi,
  I was able to install 3-node RDO juno-1 (rdo-release-juno-1.noarch) over CentOS7, but at the end of install it gave me this ...
Questions prefixed with Q: inline below:

Additional information:
* Time synchronization installation was skipped. Please note that unsynchronized time on server instances might be problem for some OpenStack components.

Q: Do i need to sue ntpd to ensure all my systems are in sync, whats the recommended way here ?

* Warning: NetworkManager is active on <IP1>, <IP2> and <IP3>. OpenStack networking currently does not work on systems that have the Network Manager service enabled.

Q: Do i need to disable NetworkManager.service on all or is it safe to ignore this? What exactly doesn't work with NetworkManager ?

For my system it looks like below :
[root@rhsdev1 packstack]# systemctl status NetworkManager.service
NetworkManager.service - Network Manager
   Loaded: loaded (/usr/lib/systemd/system/NetworkManager.service; enabled)
   Active: active (running) since Wed 2014-12-24 23:45:56 IST; 4 days ago
 Main PID: 2002 (NetworkManager)

[root@rhsdev1 packstack]# systemctl status network.service
network.service - LSB: Bring up/down networking
   Loaded: loaded (/etc/rc.d/init.d/network)
   Active: failed (Result: exit-code) since Wed 2014-12-24 23:45:57 IST; 4 days ago


thanx,
deepak