net/interface-topology

A map of ssh public keys to install for the root user

This parameter defines what the local network interface topology on a machine should look like, as expressed in netplan format. https://netplan.io/reference defines how this param must be formatted, with a few key differences:

• It only supports systemd-networkd and old-style Redhat network configurations as output formats. Debian style is a planned on, and NetworkManager style is a lower priority.

• No support for configuring wireless interfaces or tunnel devices. Wireless support is omitted because this tool is mainly intended for servers and other devices that do not have wireless interfaces. Tunnel devices are omitted primarily due to developer bandwidth constraints.

• No support for NIC renaming or MAC address reassignment. Support may be added at a later date.

• Where ther netplan.io spec calls for glob expansion when matching names or device drivers, we also allow full regular expressions, as long as the match in question starts with ^.

• No support for per-interface backend renderers. This just doesn't seem like a good idea if you don't care about dynamic interface reconfiguration.

• Support for a few interesting generic interface match names in the netplan:

  • bootif is the interface the system last booted from, as recorded by the last-boot-macaddr Param.

  • onboard:1 ... onboard:n The first through nth onboard nics. Whether a nic is onboard or not is determined by what udev thinks.

  • pci:1 ... pci:n The first through nth nic in PCI expansion slots. These nics are always ordered by their PCI bus ordering, which can vary on a system by system basis.

  • usb:1 ... usb:n The first through nth USB nics, also ordered by bus order. If you want to use one of these, make sure it stays plugged in to the same USB port.

This param primarily concerns itself with topology, not address management, which is handled by the net/interface-config param instead. As such, you should not include any addresses, routes, etc in this param. If you do, they will be overridden by matching fields for the matching interface IDs in the net/interface-config param. In netplan terminollogy, this param should contain a match stanza for each ID that requires it, along with any device-specific properties required for virtual devices ( vlan ID, bridge configuration settings, bond modes, etc).

The default for ths parameter is

  network:
    version: 2

which leaves the network topology on the machine alone. A contrived example which bonds the onboard interfaces, bridges that bond with all the interfaces on expansion cards, and then creates a VLAN interface on top of that is as follows:

network:
  version: 2
  ethernets:
    onboards:
      match:
        name: '^onboard:.*'
    others:
      match:
        name: pci:*
  bonds:
    bond0:
      interfaces: [ onboards ]
      parameters:
        mode: '802.3ad'
  bridges:
    bridge0:
      interfaces: [ others, bond0 ]
  vlans:
    vlan0:
      id: 1000
      link: bridge0

Many other topologies are possible.