# Configure remote console access

OpenStack provides a number of different methods to interact with your guests: VNC, SPICE, Serial, RDP or MKS. If configured, these can be accessed by users through the OpenStack dashboard or the command line. This document outlines how these different technologies can be configured.

## Overview

It is considered best practice to deploy only one of the consoles types and not all console types are supported by all compute drivers. Regardless of what option is chosen, a console proxy service is required. These proxy services are responsible for the following:

- Provide a bridge between the public network where the clients live and the private network where the servers with consoles live.

- Mediate token authentication.

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

For some combinations of compute driver and console driver, these proxy services are provided by the hypervisor or another service. For all others, nova provides services to handle this proxying. Consider a noVNC-based VNC console connection for example:

1. A user connects to the API and gets an `access_url` such as, `http://ip:port/?path=%3Ftoken%3Dxyz`.

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

3. The browser or client connects to the proxy.

4. The proxy authorizes 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 `vnc.server_proxyclient_address` option. In this way, the VNC proxy works as a bridge between the public network and private host network.

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

This means a typical deployment with noVNC-based VNC consoles will have the following components:

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

- One or more nova-compute services. Hosts the instances for which consoles are provided.

Todo

The below diagram references nova-consoleauth and needs to be updated.

This particular example is illustrated below.

## Consoleauth configuration:

The consoleauth accepts following options:

- `consoleauth.token_ttl`

- `consoleauth.enforce_session_timeout`

    [consoleauth]
    token_ttl = 1000                    # default value is 600 second
    enforce_session_timeout = True      # default is False

## Supported consoles:

- noVNC-based VNC console

- SPICE console

- Serial console

- MKS console

## noVNC-based VNC console

VNC is a graphical console with wide support among many hypervisors and clients. noVNC provides VNC support through a web browser.

Note

It has been reported that versions of noVNC older than 0.6 do not work with the nova-novncproxy service.

If using non-US key mappings, you need at least noVNC 1.0.0 for a fix.

If using VMware ESX/ESXi hypervisors, you need at least noVNC 1.1.0 for a fix.

### Configuration

To enable the noVNC VNC console service, you must configure both the nova-novncproxy service and the nova-compute service. Most options are defined in the `vnc` group.

The nova-novncproxy service accepts the following options:

- `daemon`

- `ssl_only`

- `source_is_ipv6`

- `cert`

- `key`

- `web`

- `console.ssl_ciphers`

- `console.ssl_minimum_version`

- `vnc.novncproxy_host`

- `vnc.novncproxy_port`

If using the libvirt compute driver and enabling VNC proxy security, the following additional options are supported:

- `vnc.auth_schemes`

- `vnc.vencrypt_client_key`

- `vnc.vencrypt_client_cert`

- `vnc.vencrypt_ca_certs`

For example, to configure this via a `nova-novncproxy.conf` file:

    [vnc]
    novncproxy_host = 0.0.0.0
    novncproxy_port = 6082

Note

This doesn’t show configuration with security. For information on how to configure this, refer to VNC proxy security below.

The nova-compute service requires the following options to configure noVNC-based VNC console support:

- `vnc.enabled`

- `vnc.novncproxy_base_url`

- `vnc.server_listen`

- `vnc.server_proxyclient_address`

If using the VMware compute driver, the following additional options are supported:

- `vmware.vnc_port`

- `vmware.vnc_port_total`

For example, to configure this via a `nova.conf` file:

    [vnc]
    enabled = True
    novncproxy_base_url = http://IP_ADDRESS:6082/vnc_auto.html
    server_listen = 127.0.0.1
    server_proxyclient_address = 127.0.0.1

Replace `IP_ADDRESS` with the IP address from which the proxy is accessible by the outside world. For example, this may be the management interface IP address of the controller or the VIP.

If using the ironic hypervisor driver, the following additional option is supported:

- `ironic.vnc_console_state_timeout`

### VNC proxy security

Deploy the public-facing interface of the VNC proxy with HTTPS to prevent attacks from malicious parties on the network between the tenant user and proxy server. When using HTTPS, the TLS encryption only applies to data between the tenant user and proxy server. The data between the proxy server and Compute node instance will still be unencrypted. To provide protection for the latter, it is necessary to enable the VeNCrypt authentication scheme for VNC in both the Compute nodes and noVNC proxy server hosts.

#### QEMU/KVM Compute node configuration

Ensure each Compute node running QEMU/KVM with libvirt has a set of certificates issued to it. The following is a list of the required certificates:

- `/etc/pki/libvirt-vnc/server-cert.pem`

  An x509 certificate to be presented by the VNC server. The `CommonName` should match the primary hostname of the compute node. Use of `subjectAltName` is also permitted if there is a need to use multiple hostnames or IP addresses to access the same Compute node.

- `/etc/pki/libvirt-vnc/server-key.pem`

  The private key used to generate the `server-cert.pem` file.

- `/etc/pki/libvirt-vnc/ca-cert.pem`

  The authority certificate used to sign `server-cert.pem` and sign the VNC proxy server certificates.

The certificates must have v3 basic constraints [2] present to indicate the permitted key use and purpose data.

We recommend using a dedicated certificate authority solely for the VNC service. This authority may be a child of the master certificate authority used for the OpenStack deployment. This is because libvirt does not currently have a mechanism to restrict what certificates can be presented by the proxy server.

For further details on certificate creation, consult the QEMU manual page documentation on VNC server certificate setup [1].

Configure libvirt to enable the VeNCrypt authentication scheme for the VNC server. In `/etc/libvirt/qemu.conf`, uncomment the following settings:

- `vnc_tls=1`

  This instructs libvirt to enable the VeNCrypt authentication scheme when launching QEMU, passing it the certificates shown above.

- `vnc_tls_x509_verify=1`

  This instructs QEMU to require that all VNC clients present a valid x509 certificate. Assuming a dedicated certificate authority is used for the VNC service, this ensures that only approved VNC proxy servers can connect to the Compute nodes.

Make sure to provide correct permissions to the certificate files for the process which creates instance. Please follow the libvirt wiki page [3] for the same.

After editing `qemu.conf`, the `libvirtd` service must be restarted:

    $ systemctl restart libvirtd.service

Changes will not apply to any existing running guests on the Compute node, so this configuration should be done before launching any instances.

#### noVNC proxy server configuration

The noVNC proxy server initially only supports the `none` authentication scheme, which does no checking. Therefore, it is necessary to enable the `vencrypt` authentication scheme by editing the `nova.conf` file to set.

    [vnc]
    auth_schemes=vencrypt,none

Note

Enabling `vencrypt` is not yet implemented for ironic, so this is not yet supported for the ironic hypervisor driver.

The `vnc.auth_schemes` values should be listed in order of preference. If enabling VeNCrypt on an existing deployment which already has instances running, the noVNC proxy server must initially be allowed to use `vencrypt` and `none`. Once it is confirmed that all Compute nodes have VeNCrypt enabled for VNC, it is possible to remove the `none` option from the list of the `vnc.auth_schemes` values.

At that point, the noVNC proxy will refuse to connect to any Compute node that does not offer VeNCrypt.

As well as enabling the authentication scheme, it is necessary to provide certificates to the noVNC proxy.

- `/etc/pki/nova-novncproxy/client-cert.pem`

  An x509 certificate to be presented to the VNC server. While libvirt/QEMU will not currently do any validation of the `CommonName` field, future versions will allow for setting up access controls based on the `CommonName`. The `CommonName` field should match the primary hostname of the controller node. If using a HA deployment, the `Organization` field can also be configured to a value that is common across all console proxy instances in the deployment. This avoids the need to modify each compute node’s whitelist every time a console proxy instance is added or removed.

- `/etc/pki/nova-novncproxy/client-key.pem`

  The private key used to generate the `client-cert.pem` file.

- `/etc/pki/nova-novncproxy/ca-cert.pem`

  The certificate authority cert used to sign `client-cert.pem` and sign the compute node VNC server certificates.

The certificates must have v3 basic constraints [2] present to indicate the permitted key use and purpose data.

Once the certificates have been created, the noVNC console proxy service must be told where to find them. This requires editing `nova.conf` to set.

    [vnc]
    vencrypt_client_key=/etc/pki/nova-novncproxy/client-key.pem
    vencrypt_client_cert=/etc/pki/nova-novncproxy/client-cert.pem
    vencrypt_ca_certs=/etc/pki/nova-novncproxy/ca-cert.pem

## SPICE console

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 with the nova-spicehtml5proxy service by using SPICE-over-websockets. The nova-spicehtml5proxy service communicates directly with the hypervisor process by using SPICE.

### Configuration

Important

VNC must be explicitly disabled to get access to the SPICE console. Set the `vnc.enabled` option to `False` to disable the VNC console.

To enable the SPICE console service, you must configure both the nova-spicehtml5proxy service and the nova-compute service. Most options are defined in the `spice` group.

The nova-spicehtml5proxy service accepts the following options.

- `daemon`

- `ssl_only`

- `source_is_ipv6`

- `cert`

- `key`

- `web`

- `console.ssl_ciphers`

- `console.ssl_minimum_version`

- `spice.html5proxy_host`

- `spice.html5proxy_port`

For example, to configure this via a `nova-spicehtml5proxy.conf` file:

    [spice]
    html5proxy_host = 0.0.0.0
    html5proxy_port = 6082

The nova-compute service requires the following options to configure SPICE console support.

- `spice.enabled`

- `spice.agent_enabled`

- `spice.html5proxy_base_url`

- `spice.server_listen`

- `spice.server_proxyclient_address`

For example, to configure this via a `nova.conf` file:

    [spice]
    agent_enabled = False
    enabled = True
    html5proxy_base_url = http://IP_ADDRESS:6082/spice_auto.html
    server_listen = 127.0.0.1
    server_proxyclient_address = 127.0.0.1

Replace `IP_ADDRESS` with the IP address from which the proxy is accessible by the outside world. For example, this may be the management interface IP address of the controller or the VIP.

Optionally, the nova-compute service supports the following additional options to configure compression settings (algorithms and modes) for SPICE consoles.

- `spice.image_compression`

- `spice.jpeg_compression`

- `spice.zlib_compression`

- `spice.playback_compression`

- `spice.streaming_mode`

As well as the following option to require that connections be protected by TLS:

- `spice.require_secure`

## Serial console

Serial consoles provide an alternative to graphical consoles like VNC or SPICE. They work a little differently to graphical consoles so an example is beneficial. The example below uses these nodes:

- controller node with IP `192.168.50.100`

- compute node 1 with IP `192.168.50.104`

- compute node 2 with IP `192.168.50.105`

Here’s the general flow of actions:

1. The user requests a serial console connection string for an instance from the REST API.

2. The Compute API service asks the nova-compute service, which manages that instance, to fulfill that request.

3. That connection string gets used by the user to connect to the nova-serialproxy service.

4. The nova-serialproxy service then proxies the console interaction to the port of the compute node where the instance is running. That port gets forwarded by the hypervisor (or ironic conductor, for ironic) to the guest.

### Configuration

To enable the serial console service, you must configure both the nova-serialproxy service and the nova-compute service. Most options are defined in the `serial_console` group.

The nova-serialproxy service accepts the following options.

- `daemon`

- `ssl_only`

- `source_is_ipv6`

- `cert`

- `key`

- `web`

- `console.ssl_ciphers`

- `console.ssl_minimum_version`

- `serial_console.serialproxy_host`

- `serial_console.serialproxy_port`

For example, to configure this via a `nova-serialproxy.conf` file:

    [serial_console]
    serialproxy_host = 0.0.0.0
    serialproxy_port = 6083

The nova-compute service requires the following options to configure serial console support.

- `serial_console.enabled`

- `serial_console.base_url`

- `serial_console.proxyclient_address`

- `serial_console.port_range`

For example, to configure this via a `nova.conf` file:

    [serial_console]
    enabled = True
    base_url = ws://IP_ADDRESS:6083/
    proxyclient_address = 127.0.0.1
    port_range = 10000:20000

Replace `IP_ADDRESS` with the IP address from which the proxy is accessible by the outside world. For example, this may be the management interface IP address of the controller or the VIP.

There are some things to keep in mind when configuring these options:

- `serial_console.serialproxy_host` is the address the nova-serialproxy service listens to for incoming connections.

- `serial_console.serialproxy_port` must be the same value as the port in the URI of `serial_console.base_url`.

- The URL defined in `serial_console.base_url` will form part of the response the user will get when asking for a serial console connection string. This means it needs to be an URL the user can connect to.

- `serial_console.proxyclient_address` will be used by the nova-serialproxy service to determine where to connect to for proxying the console interaction.

## MKS console

MKS is the protocol used for accessing the console of a virtual machine running on VMware vSphere. It is very similar to VNC. Due to the architecture of the VMware vSphere hypervisor, it is not necessary to run a console proxy service.

### Configuration

To enable the MKS console service, only the nova-compute service must be configured. All options are defined in the `mks` group.

The nova-compute service requires the following options to configure MKS console support.

- `mks.enabled`

- `mks.mksproxy_base_url`

For example, to configure this via a `nova.conf` file:

    [mks]
    enabled = True
    mksproxy_base_url = https://127.0.0.1:6090/

## About `nova-consoleauth`

The now-removed nova-consoleauth service was previously used to provide a shared service to manage token authentication that the client proxies outlined below could leverage. Token authentication was moved to the database in 18.0.0 (Rocky) and the service was removed in 20.0.0 (Train).

## Frequently Asked Questions

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

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

- 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:

      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:

      [vnc]
      # These flags help construct a connection data structure
      server_proxyclient_address=192.168.1.2
      novncproxy_base_url=http://172.24.1.1:6080/vnc_auto.html

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

  Note

  `novncproxy_base_url` uses 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 `server_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:

      <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.

- Q: How do I know which nova config file to update to set a particular config option?

  A: First, find out which nova-service is responsible for the change you want to make, using `ps -aux | grep nova`. Once the service is found, check the status of the service via systemctl. In the status output, associated conf files with respective paths will be listed.

## References

[1]

https://qemu.weilnetz.de/doc/4.2/qemu-doc.html#vnc_005fsec_005fcertificate_005fverify

[2] (1,2)

https://tools.ietf.org/html/rfc3280#section-4.2.1.10

[3]

https://wiki.libvirt.org/page/VNCTLSSetup#Changes_to_be_made_on_the_virtualisation_host_server

this page last updated: 2026-06-08 08:40:45

Except where otherwise noted, this document is licensed under Creative Commons Attribution 3.0 License. See all OpenStack Legal Documents.

found an error? report a bug