ironic/doc/source/install/graphical-console.rst

Graphical console support

The Bare Metal service supports displaying graphical consoles from a number of hardware vendors.

The following preconditions are required for a node's graphical console to be viewable:

• Service ironic-conductor has a configured console container provider appropriate for the environment
• Service ironic-novncproxy is configured and running
• The node's console_interface is set to a graphical driver such as redfish-graphical

When enabled and configured, the following sequence occurs when a graphical console is accessed when interacting with Bare Metal service directly:

• A REST API call is made to enable the console, for example via the CLI command baremetal node console enable
• ironic-conductor creates and stores a time-limited token with the node
• ironic-conductor triggers starting a container which runs a virtual X11 display, starts a web browser, and exposes a VNC server
• Once enabled, a REST API call is made to fetch the console URL, for example via the CLI command baremetal node console show
• The user accesses the console URL with a web browser
• ironic-novncproxy serves the NoVNC web assets to the browser
• A websocket is initiated with ironic-novncproxy, which looks up the node and validates the token
• ironic-novncproxy makes a VNC connection with the console container and proxies VNC traffic between the container and the browser
• The container initiates a connection with the node's BMC Redfish endpoint and determines which vendor script to run
• The container makes Redfish calls and simulates a browser user to display an HTML5 console, which the end user can now view

Building a console container

The tools/vnc-container directory contains the files and instructions to build a console container. This directory will be where further development occurs, and currently only a CentOS Stream based image can be built.

Container providers

ironic-conductor must be configured with a container provider so that it can trigger starting and stopping console containers based on node's console enabled state. Given the variety of deployment architectures for Ironic, an appropriate container provider needs to be configured.

In many cases this will require writing an external custom container provider, especially when Ironic itself is deployed in a containerized environment.

Systemd container provider

The only functional container provider included is the systemd provider which manages containers as Systemd Quadlet containers. This provider is appropriate to use when the Ironic services themselves are not containerised, and is also a good match when ironic-conductor itself is managed as a Systemd unit.

To start a container, this provider writes .container files to /etc/containers/systemd/users/{uid}/containers/systemd then calls systemctl --user daemon-reload to generate a unit file which is then started with systemctl --user start {unit name}.

Creating an external container provider

An external python library can contribute its own container provider by subclassing ironic.console.container.base.BaseConsoleContainer then adding it to the library's setup.cfg [entry_points]ironic.console.container.

The start_container method must return the IP and port of the resulting running VNC server, which in most scenarios would mean blocking until the container is running.

Networking requirements

ironic-novncproxy

Like ironic-api, ironic-novncproxy presents a public endpoint. However unlike ironic-api, node console URLs are coupled to the ironic-conductor managing that node, so load balancing across all ironic-novncproxy instances is not appropriate.

A TLS enabled reverse proxy needs to support WebSockets, otherwise TLS can be enabled in the ironic.conf [vnc] section.

ironic-novncproxy needs to be able to connect to the VNC servers exposed by the console containers.

Console containers

The VNC servers exposed by console containers are unencrypted and unauthenticated, so public access must be restricted via another network configuration mechanism. The ironic-novncproxy service needs to access the VNC server exposed by these containers, and so does nova-novncproxy when Nova is using the Ironic driver.

For the systemd container the VNC server will be published on a random high port number.

Console containers need access to the management network to access the BMC web interface. If driver_info redfish_verify_ca=False then web requests will not be verified by the browser. Setting redfish_verify_ca to a certificate path is not yet supported by the systemd container provider as the certificate is not bind-mounted into the container. This can be supported locally by building a container which includes the expected certificate files.