How to select virtual consoles
One decision a cloud architect will need to make regarding Compute service
configuration is whether to use VNC
or SPICE.
Virtual Network Computer (VNC)
OpenStack can be configured to provide remote desktop console access to
instances for tenants and administrators using the Virtual Network Computer
(VNC) protocol.
Capabilities
- The OpenStack Dashboard (horizon) can provide a VNC console for instances
directly on the web page using the HTML5 noVNC client. This requires the
nova-novncproxy
service to bridge from the public network to the
management network.
- The
nova
command-line utility can return a URL for the VNC console for
access by the nova Java VNC client. This requires the nova-xvpvncproxy
service to bridge from the public network to the management network.
Security considerations
- The
nova-novncproxy
and nova-xvpvncproxy
services by default open
public-facing ports that are token authenticated.
- By default, the remote desktop traffic is not encrypted. TLS can be enabled
to encrypt the VNC traffic. Refer to
Introduction to TLS and SSL
for appropriate recommendations.
Simple Protocol for Independent Computing Environments (SPICE)
As an alternative to VNC, OpenStack provides remote desktop access to guest
virtual machines using the Simple Protocol for Independent Computing
Environments (SPICE) protocol.
Capabilities
- SPICE is supported by the OpenStack Dashboard (horizon) directly on the
instance web page. This requires the
nova-spicehtml5proxy
service.
- The nova command-line utility can return a URL for SPICE console for access
by a SPICE-html client.
Limitations
- Although SPICE has many advantages over VNC, the spice-html5 browser
integration currently does not allow administrators to take advantage of
the benefits. To take advantage of SPICE features like multi-monitor,
USB pass through, we recommend administrators use a standalone SPICE
client within the management network.
Security considerations
- The
nova-spicehtml5proxy
service by default opens public-facing ports
that are token authenticated.
- The functionality and integration are still evolving. We will access the
features in the next release and make recommendations.
- As is the case for VNC, at this time we recommend using SPICE from the
management network in addition to limiting use to few individuals.
Bibliography
- OpenStack Admin Guide. SPICE Console. SPICE Console.
- bugzilla.redhat.com, Bug 913607 - RFE: Support Tunnelling SPICE over
websockets. 2013. RedHat bug 913607.