Type: nic

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Note

The nic device type is supported for both containers and VMs.

NICs support hotplugging for both containers and VMs (with the exception of the ipvlan NIC type).

Network devices, also referred to as Network Interface Controllers or NICs, supply a connection to a network. LXD supports several different types of network devices (NIC types).

nictype vs. network

When adding a network device to an instance, there are two methods to specify the type of device that you want to add: through the nictype device option or the network device option.

These two device options are mutually exclusive, and you can specify only one of them when you create a device. However, note that when you specify the network option, the nictype option is derived automatically from the network type.

nictype

When using the nictype device option, you can specify a network interface that is not controlled by LXD. Therefore, you must specify all information that LXD needs to use the network interface.

When using this method, the nictype option must be specified when creating the device, and it cannot be changed later.

network

When using the network device option, the NIC is linked to an existing managed network. In this case, LXD has all required information about the network, and you need to specify only the network name when adding the device.

When using this method, LXD derives the nictype option automatically. The value is read-only and cannot be changed.

Other device options that are inherited from the network are marked with a “yes” in the “Managed” column of the NIC-specific tables of device options. You cannot customize these options directly for the NIC if you’re using the network method.

See About networking for more information.

Available NIC types

The following NICs can be added using the nictype or network options:

• bridged: Uses an existing bridge on the host and creates a virtual device pair to connect the host bridge to the instance.

• macvlan: Sets up a new network device based on an existing one, but using a different MAC address.

• sriov: Passes a virtual function of an SR-IOV-enabled physical network device into the instance.

• physical: Passes a physical device from the host through to the instance. The targeted device will vanish from the host and appear in the instance.

The following NICs can be added using only the network option:

• ovn: Uses an existing OVN network and creates a virtual device pair to connect the instance to it.

The following NICs can be added using only the nictype option:

• ipvlan: Sets up a new network device based on an existing one, using the same MAC address but a different IP.

• p2p: Creates a virtual device pair, putting one side in the instance and leaving the other side on the host.

• routed: Creates a virtual device pair to connect the host to the instance and sets up static routes and proxy ARP/NDP entries to allow the instance to join the network of a designated parent interface.

The available device options depend on the NIC type and are listed in the tables in the following sections.

nictype: bridged

Note

You can select this NIC type through the nictype option or the network option (see Bridge network for information about the managed bridge network).

A bridged NIC uses an existing bridge on the host and creates a virtual device pair to connect the host bridge to the instance.

Device options

NIC devices of type bridged have the following device options:

Key	Type	Default	Managed	Description
boot.priority	integer	-	no	Boot priority for VMs (higher value boots first)
host_name	string	randomly assigned	no	The name of the interface inside the host
hwaddr	string	randomly assigned	no	The MAC address of the new interface
ipv4.address	string	-	no	An IPv4 address to assign to the instance through DHCP (can be none to restrict all IPv4 traffic when security.ipv4_filtering is set)
ipv4.routes	string	-	no	Comma-delimited list of IPv4 static routes to add on host to NIC
ipv4.routes.external	string	-	no	Comma-delimited list of IPv4 static routes to route to the NIC and publish on uplink network (BGP)
ipv6.address	string	-	no	An IPv6 address to assign to the instance through DHCP (can be none to restrict all IPv6 traffic when security.ipv6_filtering is set)
ipv6.routes	string	-	no	Comma-delimited list of IPv6 static routes to add on host to NIC
ipv6.routes.external	string	-	no	Comma-delimited list of IPv6 static routes to route to the NIC and publish on uplink network (BGP)
limits.egress	string	-	no	I/O limit in bit/s for outgoing traffic (various suffixes supported, see Units for storage and network limits)
limits.ingress	string	-	no	I/O limit in bit/s for incoming traffic (various suffixes supported, see Units for storage and network limits)
limits.max	string	-	no	I/O limit in bit/s for both incoming and outgoing traffic (same as setting both limits.ingress and limits.egress)
limits.priority	integer	-	no	The skb->priority value (32-bit unsigned integer) for outgoing traffic, to be used by the kernel queuing discipline (qdisc) to prioritize network packets (The effect of this value depends on the particular qdisc implementation, for example, SKBPRIO or QFQ. Consult the kernel qdisc documentation before setting this value.)
maas.subnet.ipv4	string	-	yes	MAAS IPv4 subnet to register the instance in
maas.subnet.ipv6	string	-	yes	MAAS IPv6 subnet to register the instance in
mtu	integer	parent MTU	yes	The MTU of the new interface
name	string	kernel assigned	no	The name of the interface inside the instance
network	string	-	no	The managed network to link the device to (instead of specifying the nictype directly)
parent	string	-	yes	The name of the host device (required if specifying the nictype directly)
security.ipv4_filtering	bool	false	no	Prevent the instance from spoofing another instance’s IPv4 address (enables security.mac_filtering)
security.ipv6_filtering	bool	false	no	Prevent the instance from spoofing another instance’s IPv6 address (enables security.mac_filtering)
security.mac_filtering	bool	false	no	Prevent the instance from spoofing another instance’s MAC address
security.port_isolation	bool	false	no	Prevent the NIC from communicating with other NICs in the network that have port isolation enabled
vlan	integer	-	no	The VLAN ID to use for non-tagged traffic (can be none to remove port from default VLAN)
vlan.tagged	integer	-	no	Comma-delimited list of VLAN IDs or VLAN ranges to join for tagged traffic

nictype: macvlan

Note

You can select this NIC type through the nictype option or the network option (see Macvlan network for information about the managed macvlan network).

A macvlan NIC sets up a new network device based on an existing one, but using a different MAC address.

If you are using a macvlan NIC, communication between the LXD host and the instances is not possible. Both the host and the instances can talk to the gateway, but they cannot communicate directly.

Device options

NIC devices of type macvlan have the following device options:

Key	Type	Default	Managed	Description
boot.priority	integer	-	no	Boot priority for VMs (higher value boots first)
gvrp	bool	false	no	Register VLAN using GARP VLAN Registration Protocol
hwaddr	string	randomly assigned	no	The MAC address of the new interface
maas.subnet.ipv4	string	-	yes	MAAS IPv4 subnet to register the instance in
maas.subnet.ipv6	string	-	yes	MAAS IPv6 subnet to register the instance in
mtu	integer	parent MTU	yes	The MTU of the new interface
name	string	kernel assigned	no	The name of the interface inside the instance
network	string	-	no	The managed network to link the device to (instead of specifying the nictype directly)
parent	string	-	yes	The name of the host device (required if specifying the nictype directly)
vlan	integer	-	no	The VLAN ID to attach to

nictype: sriov

Note

You can select this NIC type through the nictype option or the network option (see SR-IOV network for information about the managed sriov network).

An sriov NIC passes a virtual function of an SR-IOV-enabled physical network device into the instance.

An SR-IOV-enabled network device associates a set of virtual functions (VFs) with the single physical function (PF) of the network device. PFs are standard PCIe functions. VFs, on the other hand, are very lightweight PCIe functions that are optimized for data movement. They come with a limited set of configuration capabilities to prevent changing properties of the PF.

Given that VFs appear as regular PCIe devices to the system, they can be passed to instances just like a regular physical device.

VF allocation

The sriov interface type expects to be passed the name of an SR-IOV enabled network device on the system via the parent property. LXD then checks for any available VFs on the system.

By default, LXD allocates the first free VF it finds. If it detects that either none are enabled or all currently enabled VFs are in use, it bumps the number of supported VFs to the maximum value and uses the first free VF. If all possible VFs are in use or the kernel or card doesn’t support incrementing the number of VFs, LXD returns an error.

Note

If you need LXD to use a specific VF, use a physical NIC instead of a sriov NIC and set its parent option to the VF name.

Device options

NIC devices of type sriov have the following device options:

Key	Type	Default	Managed	Description
boot.priority	integer	-	no	Boot priority for VMs (higher value boots first)
hwaddr	string	randomly assigned	no	The MAC address of the new interface
maas.subnet.ipv4	string	-	yes	MAAS IPv4 subnet to register the instance in
maas.subnet.ipv6	string	-	yes	MAAS IPv6 subnet to register the instance in
mtu	integer	kernel assigned	yes	The MTU of the new interface
name	string	kernel assigned	no	The name of the interface inside the instance
network	string	-	no	The managed network to link the device to (instead of specifying the nictype directly)
parent	string	-	yes	The name of the host device (required if specifying the nictype directly)
security.mac_filtering	bool	false	no	Prevent the instance from spoofing another instance’s MAC address
vlan	integer	-	no	The VLAN ID to attach to

nictype: ovn

Note

You can select this NIC type only through the network option (see OVN network for information about the managed ovn network).

An ovn NIC uses an existing OVN network and creates a virtual device pair to connect the instance to it.

SR-IOV hardware acceleration

To use acceleration=sriov, you must have a compatible SR-IOV physical NIC that supports the Ethernet switch device driver model (switchdev) in your LXD host. LXD assumes that the physical NIC (PF) is configured in switchdev mode and connected to the OVN integration OVS bridge, and that it has one or more virtual functions (VFs) active.

To achieve this, follow these basic prerequisite setup steps:

1. Set up PF and VF:

   1. Activate some VFs on PF (called enp9s0f0np0 in the following example, with a PCI address of 0000:09:00.0) and unbind them.

   2. Enable switchdev mode and hw-tc-offload on the PF.

   3. Rebind the VFs.

   echo 4 > /sys/bus/pci/devices/0000:09:00.0/sriov_numvfs
   for i in $(lspci -nnn | grep "Virtual Function" | cut -d' ' -f1); do echo 0000:$i > /sys/bus/pci/drivers/mlx5_core/unbind; done
   devlink dev eswitch set pci/0000:09:00.0 mode switchdev
   ethtool -K enp9s0f0np0 hw-tc-offload on
   for i in $(lspci -nnn | grep "Virtual Function" | cut -d' ' -f1); do echo 0000:$i > /sys/bus/pci/drivers/mlx5_core/bind; done
   

2. Set up OVS by enabling hardware offload and adding the PF NIC to the integration bridge (normally called br-int):

   ovs-vsctl set open_vswitch . other_config:hw-offload=true
   systemctl restart openvswitch-switch
   ovs-vsctl add-port br-int enp9s0f0np0
   ip link set enp9s0f0np0 up
   

Device options

NIC devices of type ovn have the following device options:

Key	Type	Default	Managed	Description
acceleration	string	none	no	Enable hardware offloading (either none or sriov, see SR-IOV hardware acceleration)
boot.priority	integer	-	no	Boot priority for VMs (higher value boots first)
host_name	string	randomly assigned	no	The name of the interface inside the host
hwaddr	string	randomly assigned	no	The MAC address of the new interface
ipv4.address	string	-	no	An IPv4 address to assign to the instance through DHCP
ipv4.routes	string	-	no	Comma-delimited list of IPv4 static routes to route to the NIC
ipv4.routes.external	string	-	no	Comma-delimited list of IPv4 static routes to route to the NIC and publish on uplink network
ipv6.address	string	-	no	An IPv6 address to assign to the instance through DHCP
ipv6.routes	string	-	no	Comma-delimited list of IPv6 static routes to route to the NIC
ipv6.routes.external	string	-	no	Comma-delimited list of IPv6 static routes to route to the NIC and publish on uplink network
name	string	kernel assigned	no	The name of the interface inside the instance
network	string	-	yes	The managed network to link the device to (required)
security.acls	string	-	no	Comma-separated list of network ACLs to apply
security.acls.default.egress.action	string	reject	no	Action to use for egress traffic that doesn’t match any ACL rule
security.acls.default.egress.logged	bool	false	no	Whether to log egress traffic that doesn’t match any ACL rule
security.acls.default.ingress.action	string	reject	no	Action to use for ingress traffic that doesn’t match any ACL rule
security.acls.default.ingress.logged	bool	false	no	Whether to log ingress traffic that doesn’t match any ACL rule

nictype: physical

Note

• You can select this NIC type through the nictype option or the network option (see Physical network for information about the managed physical network).

• You can have only one physical NIC for each parent device.

A physical NIC provides straight physical device pass-through from the host. The targeted device will vanish from the host and appear in the instance (which means that you can have only one physical NIC for each targeted device).

Device options

NIC devices of type physical have the following device options:

Key	Type	Default	Description
boot.priority	integer	-	Boot priority for VMs (higher value boots first)
gvrp	bool	false	Register VLAN using GARP VLAN Registration Protocol
hwaddr	string	randomly assigned	The MAC address of the new interface
maas.subnet.ipv4	string	-	MAAS IPv4 subnet to register the instance in
maas.subnet.ipv6	string	-	MAAS IPv6 subnet to register the instance in
mtu	integer	parent MTU	The MTU of the new interface
name	string	kernel assigned	The name of the interface inside the instance
parent	string	-	The name of the host device (required)
vlan	integer	-	The VLAN ID to attach to

nictype: ipvlan

Note

• This NIC type is available only for containers, not for virtual machines.

• You can select this NIC type only through the nictype option.

• This NIC type does not support hotplugging.

An ipvlan NIC sets up a new network device based on an existing one, using the same MAC address but a different IP.

If you are using an ipvlan NIC, communication between the LXD host and the instances is not possible. Both the host and the instances can talk to the gateway, but they cannot communicate directly.

LXD currently supports IPVLAN in L2 and L3S mode. In this mode, the gateway is automatically set by LXD, but the IP addresses must be manually specified using the ipv4.address and/or ipv6.address options before the container is started.

DNS

The name servers must be configured inside the container, because they are not set automatically. To do this, set the following sysctls:

• When using IPv4 addresses:

  net.ipv4.conf.<parent>.forwarding=1
  

• When using IPv6 addresses:

  net.ipv6.conf.<parent>.forwarding=1
  net.ipv6.conf.<parent>.proxy_ndp=1
  

Device options

NIC devices of type ipvlan have the following device options:

Key	Type	Default	Description
gvrp	bool	false	Register VLAN using GARP VLAN Registration Protocol
hwaddr	string	randomly assigned	The MAC address of the new interface
ipv4.address	string	-	Comma-delimited list of IPv4 static addresses to add to the instance (in l2 mode, these can be specified as CIDR values or singular addresses using a subnet of /24)
ipv4.gateway	string	auto (l3s), - (l2)	In l3s mode, whether to add an automatic default IPv4 gateway (can be auto or none); in l2 mode, the IPv4 address of the gateway
ipv4.host_table	integer	-	The custom policy routing table ID to add IPv4 static routes to (in addition to the main routing table)
ipv6.address	string	-	Comma-delimited list of IPv6 static addresses to add to the instance (in l2 mode, these can be specified as CIDR values or singular addresses using a subnet of /64)
ipv6.gateway	string	auto (l3s), - (l2)	In l3s mode, whether to add an automatic default IPv6 gateway (can be auto or none); in l2 mode, the IPv6 address of the gateway
ipv6.host_table	integer	-	The custom policy routing table ID to add IPv6 static routes to (in addition to the main routing table)
mode	string	l3s	The IPVLAN mode (either l2 or l3s)
mtu	integer	parent MTU	The MTU of the new interface
name	string	kernel assigned	The name of the interface inside the instance
parent	string	-	The name of the host device (required)
vlan	integer	-	The VLAN ID to attach to

nictype: p2p

Note

You can select this NIC type only through the nictype option.

A p2p NIC creates a virtual device pair, putting one side in the instance and leaving the other side on the host.

Device options

NIC devices of type p2p have the following device options:

Key	Type	Default	Description
boot.priority	integer	-	Boot priority for VMs (higher value boots first)
host_name	string	randomly assigned	The name of the interface inside the host
hwaddr	string	randomly assigned	The MAC address of the new interface
ipv4.routes	string	-	Comma-delimited list of IPv4 static routes to add on host to NIC
ipv6.routes	string	-	Comma-delimited list of IPv6 static routes to add on host to NIC
limits.egress	string	-	I/O limit in bit/s for outgoing traffic (various suffixes supported, see Units for storage and network limits)
limits.ingress	string	-	I/O limit in bit/s for incoming traffic (various suffixes supported, see Units for storage and network limits)
limits.max	string	-	I/O limit in bit/s for both incoming and outgoing traffic (same as setting both limits.ingress and limits.egress)
limits.priority	integer	-	The skb->priority value (32-bit unsigned integer) for outgoing traffic, to be used by the kernel queuing discipline (qdisc) to prioritize network packets (The effect of this value depends on the particular qdisc implementation, for example, SKBPRIO or QFQ. Consult the kernel qdisc documentation before setting this value.)
mtu	integer	kernel assigned	The MTU of the new interface
name	string	kernel assigned	The name of the interface inside the instance

nictype: routed

Note

You can select this NIC type only through the nictype option.

A routed NIC creates a virtual device pair to connect the host to the instance and sets up static routes and proxy ARP/NDP entries to allow the instance to join the network of a designated parent interface. For containers it uses a virtual Ethernet device pair, and for VMs it uses a TAP device.

This NIC type is similar in operation to ipvlan, in that it allows an instance to join an external network without needing to configure a bridge and shares the host’s MAC address. However, it differs from ipvlan because it does not need IPVLAN support in the kernel, and the host and the instance can communicate with each other.

This NIC type respects netfilter rules on the host and uses the host’s routing table to route packets, which can be useful if the host is connected to multiple networks.

IP addresses, gateways and routes

You must manually specify the IP addresses (using ipv4.address and/or ipv6.address) before the instance is started.

For containers, the NIC configures the following link-local gateway IPs on the host end and sets them as the default gateways in the container’s NIC interface:

169.254.0.1
fe80::1

For VMs, the gateways must be configured manually or via a mechanism like cloud-init (see the how to guide).

Note

If your container image is configured to perform DHCP on the interface, it will likely remove the automatically added configuration. In this case, you must configure the IP addresses and gateways manually or via a mechanism like cloud-init.

The NIC type configures static routes on the host pointing to the instance’s veth interface for all of the instance’s IPs.

Multiple IP addresses

Each NIC device can have multiple IP addresses added to it.

However, it might be preferable to use multiple routed NIC interfaces instead. In this case, set the ipv4.gateway and ipv6.gateway values to none on any subsequent interfaces to avoid default gateway conflicts. Also consider specifying a different host-side address for these subsequent interfaces using ipv4.host_address and/or ipv6.host_address.

Parent interface

This NIC can operate with and without a parent network interface set.

With the parent network interface set, proxy ARP/NDP entries of the instance’s IPs are added to the parent interface, which allows the instance to join the parent interface’s network at layer 2.

To enable this, the following network configuration must be applied on the host via sysctl:

• When using IPv4 addresses:

  net.ipv4.conf.<parent>.forwarding=1
  

• When using IPv6 addresses:

  net.ipv6.conf.all.forwarding=1
  net.ipv6.conf.<parent>.forwarding=1
  net.ipv6.conf.all.proxy_ndp=1
  net.ipv6.conf.<parent>.proxy_ndp=1
  

Device options

NIC devices of type routed have the following device options:

Key	Type	Default	Description
gvrp	bool	false	Register VLAN using GARP VLAN Registration Protocol
host_name	string	randomly assigned	The name of the interface inside the host
hwaddr	string	randomly assigned	The MAC address of the new interface
ipv4.address	string	-	Comma-delimited list of IPv4 static addresses to add to the instance
ipv4.gateway	string	auto	Whether to add an automatic default IPv4 gateway (can be auto or none)
ipv4.host_address	string	169.254.0.1	The IPv4 address to add to the host-side veth interface
ipv4.host_table	integer	-	The custom policy routing table ID to add IPv4 static routes to (in addition to the main routing table)
ipv4.neighbor_probe	bool	true	Whether to probe the parent network for IP address availability
ipv4.routes	string	-	Comma-delimited list of IPv4 static routes to add on host to NIC (without L2 ARP/NDP proxy)
ipv6.address	string	-	Comma-delimited list of IPv6 static addresses to add to the instance
ipv6.gateway	string	auto	Whether to add an automatic default IPv6 gateway (can be auto or none)
ipv6.host_address	string	fe80::1	The IPv6 address to add to the host-side veth interface
ipv6.host_table	integer	-	The custom policy routing table ID to add IPv6 static routes to (in addition to the main routing table)
ipv6.neighbor_probe	bool	true	Whether to probe the parent network for IP address availability
ipv6.routes	string	-	Comma-delimited list of IPv6 static routes to add on host to NIC (without L2 ARP/NDP proxy)
limits.egress	string	-	I/O limit in bit/s for outgoing traffic (various suffixes supported, see Units for storage and network limits)
limits.ingress	string	-	I/O limit in bit/s for incoming traffic (various suffixes supported, see Units for storage and network limits)
limits.max	string	-	I/O limit in bit/s for both incoming and outgoing traffic (same as setting both limits.ingress and limits.egress)
limits.priority	integer	-	The skb->priority value (32-bit unsigned integer) for outgoing traffic, to be used by the kernel queuing discipline (qdisc) to prioritize network packets (The effect of this value depends on the particular qdisc implementation, for example, SKBPRIO or QFQ. Consult the kernel qdisc documentation before setting this value.)
mtu	integer	parent MTU	The MTU of the new interface
name	string	kernel assigned	The name of the interface inside the instance
parent	string	-	The name of the host device to join the instance to
vlan	integer	-	The VLAN ID to attach to

bridged, macvlan or ipvlan for connection to physical network

The bridged, macvlan and ipvlan interface types can be used to connect to an existing physical network.

macvlan effectively lets you fork your physical NIC, getting a second interface that is then used by the instance. This method saves you from creating a bridge device and virtual Ethernet device pairs and usually offers better performance than a bridge.

The downside to this method is that macvlan devices, while able to communicate between themselves and to the outside, cannot talk to their parent device. This means that you can’t use macvlan if you ever need your instances to talk to the host itself.

In such case, a bridge device is preferable. A bridge also lets you use MAC filtering and I/O limits, which cannot be applied to a macvlan device.

ipvlan is similar to macvlan, with the difference being that the forked device has IPs statically assigned to it and inherits the parent’s MAC address on the network.

MAAS integration

If you’re using MAAS to manage the physical network under your LXD host and want to attach your instances directly to a MAAS-managed network, LXD can be configured to interact with MAAS so that it can track your instances.

At the daemon level, you must configure maas.api.url and maas.api.key, and then set the maas.subnet.ipv4 and/or maas.subnet.ipv6 keys on the instance or profile’s nic entry.

With this configuration, LXD registers all your instances with MAAS, giving them proper DHCP leases and DNS records.

If you set the ipv4.address or ipv6.address keys on the NIC, those are registered as static assignments in MAAS.