===============================
Configure remote console access
===============================

To provide a remote console or remote desktop access to guest virtual machines,
use VNC or SPICE HTML5 through either the OpenStack dashboard or the command
line. Best practice is to select one or the other to run.

About nova-consoleauth
~~~~~~~~~~~~~~~~~~~~~~

Both client proxies leverage a shared service to manage token authentication
called ``nova-consoleauth``. This service must be running for either proxy to
work. Many proxies of either type can be run against a single
``nova-consoleauth`` service in a cluster configuration.

Do not confuse the ``nova-consoleauth`` shared service with ``nova-console``,
which is a XenAPI-specific service that most recent VNC proxy architectures do
not use.

SPICE console
~~~~~~~~~~~~~

OpenStack Compute supports VNC consoles to guests. The VNC protocol is fairly
limited, lacking support for multiple monitors, bi-directional audio, reliable
cut-and-paste, video streaming and more. SPICE is a new protocol that aims to
address the limitations in VNC and provide good remote desktop support.

SPICE support in OpenStack Compute shares a similar architecture to the VNC
implementation. The OpenStack dashboard uses a SPICE-HTML5 widget in its
console tab that communicates to the ``nova-spicehtml5proxy`` service by using
SPICE-over-websockets. The ``nova-spicehtml5proxy`` service communicates
directly with the hypervisor process by using SPICE.

VNC must be explicitly disabled to get access to the SPICE console. Set the
``vnc_enabled`` option to ``False`` in the ``[DEFAULT]`` section to disable the
VNC console.

Use the following options to configure SPICE as the console for OpenStack
Compute:

.. code-block:: console

   [spice]
   agent_enabled = False
   enabled = True
   html5proxy_base_url = http://IP_ADDRESS:6082/spice_auto.html
   html5proxy_host = 0.0.0.0
   html5proxy_port = 6082
   keymap = en-us
   server_listen = 127.0.0.1
   server_proxyclient_address = 127.0.0.1

Replace ``IP_ADDRESS`` with the management interface IP address of the
controller or the VIP.

VNC console proxy
~~~~~~~~~~~~~~~~~

The VNC proxy is an OpenStack component that enables compute service users to
access their instances through VNC clients.

.. note::

   The web proxy console URLs do not support the websocket protocol scheme
   (ws://) on python versions less than 2.7.4.

The VNC console connection works as follows:

#. A user connects to the API and gets an ``access_url`` such as,
   ``http://ip:port/?token=xyz``.

#. The user pastes the URL in a browser or uses it as a client
   parameter.

#. The browser or client connects to the proxy.

#. The proxy talks to ``nova-consoleauth`` to authorize the token for the user,
   and maps the token to the *private* host and port of the VNC server for an
   instance.

   The compute host specifies the address that the proxy should use to connect
   through the ``nova.conf`` file option, ``vncserver_proxyclient_address``. In
   this way, the VNC proxy works as a bridge between the public network and
   private host network.

#. The proxy initiates the connection to VNC server and continues to proxy
   until the session ends.

The proxy also tunnels the VNC protocol over WebSockets so that the ``noVNC``
client can talk to VNC servers. In general, the VNC proxy:

- Bridges between the public network where the clients live and the private
  network where VNC servers live.

- Mediates token authentication.

- Transparently deals with hypervisor-specific connection details to provide a
  uniform client experience.

.. figure:: figures/SCH_5009_V00_NUAC-VNC_OpenStack.png
   :alt: noVNC process
   :width: 95%

VNC configuration options
-------------------------

To customize the VNC console, use the following configuration options in your
``nova.conf`` file:

.. note::

   To support :ref:`live migration <section_configuring-compute-migrations>`,
   you cannot specify a specific IP address for ``vncserver_listen``, because
   that IP address does not exist on the destination host.

.. list-table:: **Description of VNC configuration options**
   :header-rows: 1
   :widths: 25 25

   * - Configuration option = Default value
     - Description
   * - **[DEFAULT]**
     -
   * - ``daemon = False``
     - (BoolOpt) Become a daemon (background process)
   * - ``key = None``
     - (StrOpt) SSL key file (if separate from cert)
   * - ``novncproxy_host = 0.0.0.0``
     - (StrOpt) Host on which to listen for incoming requests
   * - ``novncproxy_port = 6080``
     - (IntOpt) Port on which to listen for incoming requests
   * - ``record = False``
     - (BoolOpt) Record sessions to FILE.[session_number]
   * - ``source_is_ipv6 = False``
     - (BoolOpt) Source is ipv6
   * - ``ssl_only = False``
     - (BoolOpt) Disallow non-encrypted connections
   * - ``web = /usr/share/spice-html5``
     - (StrOpt) Run webserver on same port. Serve files from DIR.
   * - **[vmware]**
     -
   * - ``vnc_port = 5900``
     - (IntOpt) VNC starting port
   * - ``vnc_port_total = 10000``
     - vnc_port_total = 10000
   * - **[vnc]**
     -
   * - enabled = True
     - (BoolOpt) Enable VNC related features
   * - novncproxy_base_url = http://127.0.0.1:6080/vnc_auto.html
     - (StrOpt) Location of VNC console proxy, in the form
       "http://127.0.0.1:6080/vnc_auto.html"
   * - vncserver_listen = 127.0.0.1
     - (StrOpt) IP address on which instance vncservers should listen
   * - vncserver_proxyclient_address = 127.0.0.1
     - (StrOpt) The address to which proxy clients (like nova-xvpvncproxy)
       should connect
   * - xvpvncproxy_base_url = http://127.0.0.1:6081/console
     - (StrOpt) Location of nova xvp VNC console proxy, in the form
       "http://127.0.0.1:6081/console"

.. note::

   - The ``vncserver_proxyclient_address`` defaults to ``127.0.0.1``, which is
     the address of the compute host that Compute instructs proxies to use when
     connecting to instance servers.

   - For all-in-one XenServer domU deployments, set this to ``169.254.0.1.``

   - For multi-host XenServer domU deployments, set to a ``dom0 management IP``
     on the same network as the proxies.

   - For multi-host libvirt deployments, set to a host management IP on the
     same network as the proxies.

Typical deployment
------------------

A typical deployment has the following components:

- A ``nova-consoleauth`` process. Typically runs on the controller host.

- One or more ``nova-novncproxy`` services. Supports browser-based noVNC
  clients. For simple deployments, this service typically runs on the same
  machine as ``nova-api`` because it operates as a proxy between the public
  network and the private compute host network.

- One or more ``nova-xvpvncproxy`` services. Supports the special Java client
  discussed here. For simple deployments, this service typically runs on the
  same machine as ``nova-api`` because it acts as a proxy between the public
  network and the private compute host network.

- One or more compute hosts. These compute hosts must have correctly configured
  options, as follows.

nova-novncproxy (noVNC)
-----------------------

You must install the noVNC package, which contains the ``nova-novncproxy``
service. As root, run the following command:

.. code-block:: console

   # apt-get install nova-novncproxy

The service starts automatically on installation.

To restart the service, run:

.. code-block:: console

   # service nova-novncproxy restart

The configuration option parameter should point to your ``nova.conf`` file,
which includes the message queue server address and credentials.

By default, ``nova-novncproxy`` binds on ``0.0.0.0:6080``.

To connect the service to your Compute deployment, add the following
configuration options to your ``nova.conf`` file:

- ``vncserver_listen=0.0.0.0``

  Specifies the address on which the VNC service should bind. Make sure it is
  assigned one of the compute node interfaces. This address is the one used by
  your domain file.

  .. code-block:: console

     <graphics type="vnc" autoport="yes" keymap="en-us" listen="0.0.0.0"/>

  .. note::

     To use live migration, use the 0.0.0.0 address.

- ``vncserver_proxyclient_address=127.0.0.1``

  The address of the compute host that Compute instructs proxies to use when
  connecting to instance ``vncservers``.

Frequently asked questions about VNC access to virtual machines
---------------------------------------------------------------

- **Q: What is the difference between ``nova-xvpvncproxy`` and
  ``nova-novncproxy``?**

  A: ``nova-xvpvncproxy``, which ships with OpenStack Compute, is a proxy that
  supports a simple Java client. nova-novncproxy uses noVNC to provide VNC
  support through a web browser.

- **Q: I want VNC support in the OpenStack dashboard. What services do I
  need?**

  A: You need ``nova-novncproxy``, ``nova-consoleauth``, and correctly
  configured compute hosts.

- **Q: When I use ``nova get-vnc-console`` or click on the VNC tab of the
  OpenStack dashboard, it hangs. Why?**

  A: Make sure you are running ``nova-consoleauth`` (in addition to
  ``nova-novncproxy``). The proxies rely on ``nova-consoleauth`` to validate
  tokens, and waits for a reply from them until a timeout is reached.

- **Q: My VNC proxy worked fine during my all-in-one test, but now it doesn't
  work on multi host. Why?**

  A: The default options work for an all-in-one install, but changes must be
  made on your compute hosts once you start to build a cluster.  As an example,
  suppose you have two servers:

  .. code-block:: bash

     PROXYSERVER (public_ip=172.24.1.1, management_ip=192.168.1.1)
     COMPUTESERVER (management_ip=192.168.1.2)

  Your ``nova-compute`` configuration file must set the following values:

  .. code-block:: console

     # These flags help construct a connection data structure
     vncserver_proxyclient_address=192.168.1.2
     novncproxy_base_url=http://172.24.1.1:6080/vnc_auto.html
     xvpvncproxy_base_url=http://172.24.1.1:6081/console

     # This is the address where the underlying vncserver (not the proxy)
     # will listen for connections.
     vncserver_listen=192.168.1.2

  .. note::

     ``novncproxy_base_url`` and ``xvpvncproxy_base_url`` use a public IP; this
     is the URL that is ultimately returned to clients, which generally do not
     have access to your private network. Your PROXYSERVER must be able to
     reach ``vncserver_proxyclient_address``, because that is the address over
     which the VNC connection is proxied.

- **Q: My noVNC does not work with recent versions of web browsers. Why?**

  A: Make sure you have installed ``python-numpy``, which is required to
  support a newer version of the WebSocket protocol (HyBi-07+).

- **Q: How do I adjust the dimensions of the VNC window image in the OpenStack
  dashboard?**

  A: These values are hard-coded in a Django HTML template. To alter them, edit
  the ``_detail_vnc.html`` template file. The location of this file varies
  based on Linux distribution. On Ubuntu 14.04, the file is at
  ``/usr/share/pyshared/horizon/dashboards/nova/instances/templates/instances/_detail_vnc.html``.

  Modify the ``width`` and ``height`` options, as follows:

  .. code-block:: console

     <iframe src="{{ vnc_url }}" width="720" height="430"></iframe>

- **Q: My noVNC connections failed with ValidationError: Origin header protocol
  does not match. Why?**

  A: Make sure the ``base_url`` match your TLS setting. If you are using https
  console connections, make sure that the value of ``novncproxy_base_url`` is
  set explicitly where the ``nova-novncproxy`` service is running.
