Networking config Version 2#
Cloud-init
’s support for Version 2 network config is a subset of the
Version 2 format defined for the Netplan tool. Cloud-init
supports
both reading and writing of Version 2. Writing support requires a
distro with Netplan present.
Netplan passthrough#
On a system with Netplan present, cloud-init
will pass Version 2
configuration through to Netplan without modification. On such systems, you do
not need to limit yourself to the below subset of Netplan’s configuration
format.
Warning
If you are writing or generating network configuration that may be used on non-netplan systems, you must limit yourself to the subset described in this document, or you will see network configuration failures on non-netplan systems.
Version 2 configuration format#
The network
key has at least two required elements. First, it must include
version: 2
and one or more of possible device types
.
Cloud-init
will read this format from Base configuration.
For example the following could be present in
/etc/cloud/cloud.cfg.d/custom-networking.cfg
:
network:
version: 2
ethernets: []
It may also be provided in other locations including the NoCloud. See Network configuration for other places.
Supported device types
values are as follows:
ethernets
: Ethernetsbonds
: Bondsbridges
: Bridgesvlans
: VLANs
Each type
block contains device definitions as a map (where the keys are
called “configuration IDs”). Each entry under the types
may include IP
and/or device configuration.
Device configuration IDs#
The key names below the per-device-type definition maps (like ethernets:
)
are called “ID”s. They must be unique throughout the entire set of
configuration files. Their primary purpose is to serve as anchor names for
composite devices, for example to enumerate the members of a bridge that is
currently being defined.
There are two physically/structurally different classes of device definitions, and the ID field has a different interpretation for each:
Physical devices (e.g., ethernet, wifi)#
These can dynamically come and go between reboots and even during runtime
(hotplugging). In the generic case, they can be selected by match:
rules on desired properties, such as name/name pattern, MAC address,
driver, or device paths. In general these will match any number of
devices (unless they refer to properties which are unique such as the full
path or MAC address), so without further knowledge about the hardware,
these will always be considered as a group.
It is valid to specify no match rules at all, in which case the ID field is simply the interface name to be matched. This is mostly useful if you want to keep simple cases simple, and it’s how network device configuration has been done for a long time.
If there are match:
rules, then the ID field is a purely opaque name
which is only being used for references from definitions of compound
devices in the config.
Virtual devices (e.g., veth, bridge, bond)#
These are fully under the control of the config file(s) and the network
stack, i.e., these devices are being created instead of matched. Thus
match:
and set-name:
are not applicable for these, and the ID field
is the name of the created virtual device.
Common properties for physical device types#
match: <(mapping)>
#
This selects a subset of available physical devices by various hardware properties. The following configuration will then apply to all matching devices, as soon as they appear. All specified properties must match. The following properties for creating matches are supported:
name: <(scalar)>
#
Current interface name. Globs are supported, and the primary use case
for matching on names, as selecting one fixed name can be more easily
achieved with having no match:
at all and just using the ID (see
above). Note that currently only networkd
supports globbing,
NetworkManager
does not.
Example:
# all cards on second PCI bus
match:
name: enp2*
macaddress: <(scalar)>
#
Device’s MAC address in the form xx:xx:xx:xx:xx:xx. Globs are not allowed. Letters must be lowercase.
Example:
# fixed MAC address
match:
macaddress: "11:22:33:aa:bb:ff"
Note
It is best practice to “quote” all MAC addresses, since an unquoted MAC address might be incorrectly interpreted as an integer in YAML.
driver: <(scalar)>
#
Kernel driver name, corresponding to the DRIVER
udev property. Globs are
supported. Matching on driver is only supported with networkd
.
Example:
# first card of driver ``ixgbe``
match:
driver: ixgbe
name: en*s0
set-name: <(scalar)>
#
When matching on unique properties such as path or MAC, or with additional
assumptions such as “there will only ever be one wifi device”, match rules
can be written so that they only match one device. Then this property can be
used to give that device a more specific/desirable/nicer name than the default
from udev’s ifnames
. Any additional device that satisfies the match rules
will then fail to get renamed and keep the original kernel name (and dmesg
will show an error).
wakeonlan: <(bool)>
#
Enable wake on LAN. Off by default.
Common properties for all device types#
renderer: <(scalar)>
#
Use the given networking backend for this definition. Currently supported are
networkd
and NetworkManager
. This property can be specified globally
in networks:
, for a device type (e.g., in ethernets:
) or for a
particular device definition. Default is networkd
.
Note
Cloud-init
only supports networkd backend if rendering version2
config to the instance.
dhcp4: <(bool)>
#
Enable DHCP for IPv4. Off by default.
dhcp6: <(bool)>
#
Enable DHCP for IPv6. Off by default.
dhcp4-overrides and dhcp6-overrides: <(mapping)>
#
DHCP behaviour overrides. Overrides will only have an effect if the corresponding DHCP type is enabled. Refer to Netplan#dhcp-overrides for more documentation.
Note
These properties are only consumed on netplan
and networkd
renderers.
The netplan
renderer passes through
everything and the networkd
renderer consumes the following sub-properties:
hostname
*route-metric
*send-hostname
*use-dns
use-domains
use-hostname
use-mtu
*use-ntp
use-routes
*
Note
Sub-properties marked with a *
are unsupported for dhcp6-overrides
when used with the networkd
renderer.
Example:
dhcp4-overrides:
hostname: hal
route-metric: 1100
send-hostname: false
use-dns: false
use-domains: false
use-hostname: false
use-mtu: false
use-ntp: false
use-routes: false
addresses: <(sequence of scalars)>
#
Add static addresses to the interface in addition to the ones received
through DHCP or RA. Each sequence entry is in CIDR notation, i.e., of the
form addr/prefixlen
. addr
is an IPv4 or IPv6 address as recognised
by inet_pton(3)
and prefixlen
the number of bits of the subnet.
Example: addresses: [192.168.14.2/24, 2001:1::1/64]
gateway4: or gateway6: <(scalar)>
#
Deprecated, see Netplan#default-routes.
Set default gateway for IPv4/6, for manual address configuration. This
requires setting addresses
too. Gateway IPs must be in a form
recognised by inet_pton(3)
Example for IPv4: gateway4: 172.16.0.1
Example for IPv6: gateway6: 2001:4::1
mtu: <MTU SizeBytes>
#
The MTU key represents a device’s Maximum Transmission Unit, the largest size
packet or frame, specified in octets (eight-bit bytes), that can be sent in a
packet- or frame-based network. Specifying mtu
is optional.
nameservers: <(mapping)>
#
Set DNS servers and search domains, for manual address configuration. There
are two supported fields: addresses:
is a list of IPv4 or IPv6 addresses
similar to gateway*
, and search:
is a list of search domains.
Example:
nameservers:
search: [lab, home]
addresses: [8.8.8.8, FEDC::1]
routes: <(sequence of mapping)>
#
Add device specific routes. Each mapping includes a to
, via
key
with an IPv4 or IPv6 address as value. metric
is an optional value.
Example:
routes:
- to: 0.0.0.0/0
via: 10.23.2.1
metric: 3
Ethernets#
Ethernet device definitions do not support any specific properties beyond the common ones described above.
Bonds#
interfaces: <(sequence of scalars)>
#
All devices matching this ID list will be added to the bond.
Example:
ethernets:
switchports:
match: {name: "enp2*"}
[...]
bonds:
bond0:
interfaces: [switchports]
parameters: <(mapping)>
#
Customisation parameters for special bonding options. Time values are specified in seconds unless otherwise specified.
mode: <(scalar)>
#
Set the bonding mode used for the interfaces. The default is
balance-rr
(round robin). Possible values are balance-rr
,
active-backup
, balance-xor
, broadcast
, 802.3ad
,
balance-tlb
, and balance-alb
.
lacp-rate: <(scalar)>
#
Set the rate at which LACPDUs are transmitted. This is only useful
in 802.3ad mode. Possible values are slow
(30 seconds, default),
and fast
(every second).
mii-monitor-interval: <(scalar)>
#
Specifies the interval for MII monitoring (verifying if an interface
of the bond has carrier). The default is 0
; which disables MII
monitoring.
min-links: <(scalar)>
#
The minimum number of links up in a bond to consider the bond interface to be up.
transmit-hash-policy: <(scalar)>
#
Specifies the transmit hash policy for the selection of slaves. This
is only useful in balance-xor, 802.3ad and balance-tlb modes.
Possible values are layer2
, layer3+4
, layer2+3
,
encap2+3
, and encap3+4
.
ad-select: <(scalar)>
#
Set the aggregation selection mode. Possible values are stable
,
bandwidth
, and count
. This option is only used in 802.3ad mode.
all-slaves-active: <(bool)>
#
If the bond should drop duplicate frames received on inactive ports,
set this option to false
. If they should be delivered, set this
option to true
. The default value is false, and is the desirable
behaviour in most situations.
arp-interval: <(scalar)>
#
Set the interval value for how frequently ARP link monitoring should
happen. The default value is 0
, which disables ARP monitoring.
arp-ip-targets: <(sequence of scalars)>
#
IPs of other hosts on the link which should be sent ARP requests in
order to validate that a slave is up. This option is only used when
arp-interval
is set to a value other than 0
. At least one IP
address must be given for ARP link monitoring to function. Only IPv4
addresses are supported. You can specify up to 16 IP addresses. The
default value is an empty list.
arp-validate: <(scalar)>
#
Configure how ARP replies are to be validated when using ARP link
monitoring. Possible values are none
, active
, backup
,
and all
.
arp-all-targets: <(scalar)>
#
Specify whether to use any ARP IP target being up as sufficient for
a slave to be considered up; or if all the targets must be up. This
is only used for active-backup
mode when arp-validate
is
enabled. Possible values are any
and all
.
up-delay: <(scalar)>
#
Specify the delay before enabling a link once the link is physically
up. The default value is 0
.
down-delay: <(scalar)>
#
Specify the delay before disabling a link once the link has been
lost. The default value is 0
.
fail-over-mac-policy: <(scalar)>
#
Set whether to set all slaves to the same MAC address when adding
them to the bond, or how else the system should handle MAC addresses.
The possible values are none
, active
, and follow
.
gratuitous-arp: <(scalar)>
#
Specify how many ARP packets to send after failover. Once a link is
up on a new slave, a notification is sent and possibly repeated if
this value is set to a number greater than 1
. The default value
is 1
and valid values are between 1
and 255
. This only
affects active-backup
mode.
packets-per-slave: <(scalar)>
#
In balance-rr
mode, specifies the number of packets to transmit
on a slave before switching to the next. When this value is set to
0
, slaves are chosen at random. Allowable values are between
0
and 65535
. The default value is 1
. This setting is
only used in balance-rr
mode.
primary-reselect-policy: <(scalar)>
#
Set the reselection policy for the primary slave. On failure of the
active slave, the system will use this policy to decide how the new
active slave will be chosen and how recovery will be handled. The
possible values are always
, better
, and failure
.
learn-packet-interval: <(scalar)>
#
Specify the interval between sending Learning packets to each slave.
The value range is between 1
and 0x7fffffff
. The default
value is 1
. This option only affects balance-tlb
and
balance-alb
modes.
Bridges#
interfaces: <(sequence of scalars)>
#
All devices matching this ID list will be added to the bridge.
Example:
ethernets:
switchports:
match: {name: "enp2*"}
[...]
bridges:
br0:
interfaces: [switchports]
parameters: <(mapping)>
#
Customisation parameters for special bridging options. Time values are specified in seconds unless otherwise stated.
ageing-time: <(scalar)>
#
Set the period of time to keep a MAC address in the forwarding database after a packet is received.
priority: <(scalar)>
#
Set the priority value for the bridge. This value should be a number between
0
and 65535
. Lower values mean higher priority. The bridge with the
higher priority will be elected as the root bridge.
forward-delay: <(scalar)>
#
Specify the period of time the bridge will remain in Listening and
Learning states before getting to the Forwarding state. This value
should be set in seconds for the systemd
backend, and in milliseconds
for the NetworkManager
backend.
hello-time: <(scalar)>
#
Specify the interval between two hello packets being sent out from the root and designated bridges. Hello packets communicate information about the network topology.
max-age: <(scalar)>
#
Set the maximum age of a hello packet. If the last hello packet is older than that value, the bridge will attempt to become the root bridge.
path-cost: <(scalar)>
#
Set the cost of a path on the bridge. Faster interfaces should have a lower cost. This allows a finer control on the network topology so that the fastest paths are available whenever possible.
stp: <(bool)>
#
Define whether the bridge should use Spanning Tree Protocol. The default value is “true”, which means that Spanning Tree should be used.
VLANs#
id: <(scalar)>
#
VLAN ID, a number between 0 and 4094.
link: <(scalar)>
#
ID of the underlying device definition on which this VLAN gets created.
Example:
ethernets:
eno1: {...}
vlans:
en-intra:
id: 1
link: eno1
dhcp4: yes
en-vpn:
id: 2
link: eno1
address: ...
Examples#
Configure an ethernet device with networkd
, identified by its name, and
enable DHCP:
network:
version: 2
ethernets:
eno1:
dhcp4: true
This is a complex example which shows most available features:
network:
version: 2
ethernets:
# opaque ID for physical interfaces, only referred to by other stanzas
id0:
match:
macaddress: '00:11:22:33:44:55'
wakeonlan: true
dhcp4: true
addresses:
- 192.168.14.2/24
- 2001:1::1/64
gateway4: 192.168.14.1
gateway6: 2001:1::2
nameservers:
search: [foo.local, bar.local]
addresses: [8.8.8.8]
# static routes
routes:
- to: 192.0.2.0/24
via: 11.0.0.1
metric: 3
lom:
match:
driver: ixgbe
# you are responsible for setting tight enough match rules
# that only match one device if you use set-name
set-name: lom1
dhcp6: true
switchports:
# all cards on second PCI bus; unconfigured by themselves, will be added
# to br0 below
match:
name: enp2*
mtu: 1280
bonds:
bond0:
interfaces: [id0, lom]
bridges:
# the key name is the name for virtual (created) interfaces; no match: and
# set-name: allowed
br0:
# IDs of the components; switchports expands into multiple interfaces
interfaces: [wlp1s0, switchports]
dhcp4: true
vlans:
en-intra:
id: 1
link: id0
dhcp4: yes