Macro 32 Ramblings

Mind Archive

Netplan Configuration Examples

https://netplan.io/examples/

Below are a collection of example netplan configurations for common scenarios. If you see a scenario missing or have one to contribute, please file a bug against this documentation with the example using the links at the bottom of this page. Thank you!

Configuration

To configure netplan, save configuration files under /etc/netplan/ with a .yaml extension (e.g. /etc/netplan/config.yaml), then run sudo netplan apply. This command parses and applies the configuration to the system. Configuration written to disk under /etc/netplan/ will persist between reboots.

Using DHCP and static addressing

To let the interface named ‘enp3s0’ get an address via DHCP, create a YAML file with the following:

network:
    version: 2
    renderer: networkd
    ethernets:
        enp3s0:
            dhcp4: true

To instead set a static IP address, use the addresses key, which takes a list of (IPv4 or IPv6), addresses along with the subnet prefix length (e.g. /24). Gateway and DNS information can be provided as well:

network:
    version: 2
    renderer: networkd
    ethernets:
        enp3s0:
            addresses:
                - 10.10.10.2/24
            gateway4: 10.10.10.1
            nameservers:
                search: [mydomain, otherdomain]
                addresses: [10.10.10.1, 1.1.1.1]

Connecting multiple interfaces with DHCP

Many systems now include more than one network interface. Servers will commonly need to connect to multiple networks, and may require that traffic to the Internet goes through a specific interface despite all of them providing a valid gateway.

One can achieve the exact routing desired over DHCP by specifying a metric for the routes retrieved over DHCP, which will ensure some routes are preferred over others. In this example, ‘enred’ is preferred over ‘engreen’, as it has a lower route metric:

network:
    version: 2
    ethernets:
        enred:
            dhcp4: yes
            dhcp4-overrides:
                route-metric: 100
        engreen:
            dhcp4: yes
            dhcp4-overrides:
                route-metric: 200

Connecting to an open wireless network

Netplan easily supports connecting to an open wireless network (one that is not secured by a password), only requiring that the access point is defined:

network:
    version: 2
    wifis:
        wl0:
            access-points:
                opennetwork: {}
            dhcp4: yes

Connecting to a WPA Personal wireless network

Wireless devices use the ‘wifis’ key and share the same configuration options with wired ethernet devices. The wireless access point name and password should also be specified:

network:
    version: 2
    renderer: networkd
    wifis:
        wlp2s0b1:
            dhcp4: no
            dhcp6: no
            addresses: [192.168.0.21/24]
            gateway4: 192.168.0.1
            nameservers:
                addresses: [192.168.0.1, 8.8.8.8]
            access-points:
                "network_ssid_name":
                    password: "**********"

Connecting to WPA Enterprise wireless networks

It is also common to find wireless networks secured using WPA or WPA2 Enterprise, which requires additional authentication parameters.

For example, if the network is secured using WPA-EAP and TTLS:

network:
    version: 2
    wifis:
        wl0:
            access-points:
                workplace:
                    auth:
                        key-management: eap
                        method: ttls
                        anonymous-identity: "@internal.example.com"
                        identity: "joe@internal.example.com"
                        password: "v3ryS3kr1t"
            dhcp4: yes

Or, if the network is secured using WPA-EAP and TLS:

network:
    version: 2
    wifis:
        wl0:
            access-points:
                university:
                    auth:
                        key-management: eap
                        method: tls
                        anonymous-identity: "@cust.example.com"
                        identity: "cert-joe@cust.example.com"
                        ca-certificate: /etc/ssl/cust-cacrt.pem
                        client-certificate: /etc/ssl/cust-crt.pem
                        client-key: /etc/ssl/cust-key.pem
                        client-key-password: "d3cryptPr1v4t3K3y"
            dhcp4: yes

Many different modes of encryption are supported. See the Netplan reference page.

Using multiple addresses on a single interface

The addresses key can take a list of addresses to assign to an interface:

network:
    version: 2
    renderer: networkd
    ethernets:
        enp3s0:
         addresses:
             - 10.100.1.38/24
             - 10.100.1.39/24
         gateway4: 10.100.1.1

Interface aliases (e.g. eth0:0) are not supported.

Using multiple addresses with multiple gateways

Similar to the example above, interfaces with multiple addresses can be
configured with multiple gateways.

network:
    version: 2
    renderer: networkd
    ethernets:
        enp3s0:
         addresses:
             - 9.0.0.9/24
             - 10.0.0.10/24
             - 11.0.0.11/24
         #gateway4:  # unset, since we configure routes below
         routes:
             - to: 0.0.0.0/0
                 via: 9.0.0.1
                 metric: 100
             - to: 0.0.0.0/0
                 via: 10.0.0.1
                 metric: 100
             - to: 0.0.0.0/0
                 via: 11.0.0.1
                 metric: 100

Given that there are multiple addresses, each with their own gateway, we do not specify gateway4 here, and instead configure
individual routes to 0.0.0.0/0 (everywhere) using the address of the gateway for the subnet. The metric value should be adjusted
so the routing happens as expected.

DHCP can be used to receive one of the IP addresses for the interface. In this case, the default route for that address will be
automatically configured with a metric value of 100. As a short-hand for an entry under routes, gateway4 can be set to the
gateway address for one of the subnets. In that case, the route for that subnet can be omitted from routes. Its metric will be
set to 100.

Using Network Manager as a renderer

Netplan supports both networkd and Network Manager as backends. You can specify which network backend should be used to configure particular devices by using the renderer key. You can also delegate all configuration of the network to Network Manager itself by specifying only the renderer key:

network:
    version: 2
    renderer: NetworkManager

Configuring interface bonding

Bonding is configured by declaring a bond interface with a list of physical interfaces and a bonding mode. Below is an example of an active-backup bond that uses DHCP to obtain an address:

network:
    version: 2
    renderer: networkd
    bonds:
        bond0:
            dhcp4: yes
            interfaces:
                - enp3s0
                - enp4s0
            parameters:
                mode: active-backup
                primary: enp3s0

Below is an example of a system acting as a router with various bonded interfaces and different types. Note the ‘optional: true’ key declarations that allow booting to occur without waiting for those interfaces to activate fully.

network:
    version: 2
    renderer: networkd
    ethernets:
        enp1s0:
            dhcp4: no
        enp2s0:
            dhcp4: no
        enp3s0:
            dhcp4: no
            optional: true
        enp4s0:
            dhcp4: no
            optional: true
        enp5s0:
            dhcp4: no
            optional: true
        enp6s0:
            dhcp4: no
            optional: true
    bonds:
        bond-lan:
            interfaces: [enp2s0, enp3s0]
            addresses: [192.168.93.2/24]
            parameters:
                mode: 802.3ad
                mii-monitor-interval: 1
        bond-wan:
            interfaces: [enp1s0, enp4s0]
            addresses: [192.168.1.252/24]
            gateway4: 192.168.1.1
            nameservers:
                search: [local]
                addresses: [8.8.8.8, 8.8.4.4]
            parameters:
                mode: active-backup
                mii-monitor-interval: 1
                gratuitious-arp: 5
        bond-conntrack:
            interfaces: [enp5s0, enp6s0]
            addresses: [192.168.254.2/24]
            parameters:
                mode: balance-rr
                mii-monitor-interval: 1

Configuring network bridges

To create a very simple bridge consisting of a single device that uses DHCP, write:

network:
    version: 2
    renderer: networkd
    ethernets:
        enp3s0:
            dhcp4: no
    bridges:
        br0:
            dhcp4: yes
            interfaces:
                - enp3s0

A more complex example, to get libvirtd to use a specific bridge with a tagged vlan, while continuing to provide an untagged interface as well would involve:

network:
    version: 2
    renderer: networkd
    ethernets:
        enp0s25:
            dhcp4: true
    bridges:
        br0:
            addresses: [ 10.3.99.25/24 ]
            interfaces: [ vlan15 ]
    vlans:
        vlan15:
            accept-ra: no
            id: 15
            link: enp0s25

Then libvirtd would be configured to use this bridge by adding the following content to a new XML file under /etc/libvirtd/qemu/networks/. The name of the bridge in the tag as well as in need to match the name of the bridge device configured using netplan:

<network>
    <name>br0</name>
    <bridge name='br0'/>
    <forward mode="bridge"/>
</network>

Attaching VLANs to network interfaces

To configure multiple VLANs with renamed interfaces:

network:
    version: 2
    renderer: networkd
    ethernets:
        mainif:
            match:
                macaddress: "de:ad:be:ef:ca:fe"
            set-name: mainif
            addresses: [ "10.3.0.5/23" ]
            gateway4: 10.3.0.1
            nameservers:
                addresses: [ "8.8.8.8", "8.8.4.4" ]
                search: [ example.com ]
    vlans:
        vlan15:
            id: 15
            link: mainif
            addresses: [ "10.3.99.5/24" ]
        vlan10:
            id: 10
            link: mainif
            addresses: [ "10.3.98.5/24" ]
            nameservers:
                addresses: [ "127.0.0.1" ]
                search: [ domain1.example.com, domain2.example.com ]

Reaching a directly connected gateway

This allows setting up a default route, or any route, using the “on-link” keyword where the gateway is an IP address that is directly connected to the network even if the address does not match the subnet configured on the interface.

network:
    version: 2
    renderer: networkd
    ethernets:
        addresses: [ "10.10.10.1/24" ]
        routes:
            - to: 0.0.0.0/0
                via: 9.9.9.9
                on-link: true

For IPv6 the config would be very similar, with the notable difference being an additional scope: link host route to the router’s address required:

network:
    version: 2
    renderer: networkd
    ethernets:
        addresses: [ "2001:cafe:face:beef::dead:dead/64" ]
        routes:
            - to: "2001:cafe:face::1/128"
                scope: link
            - to: "::/0"
                via: "2001:cafe:face::1"
                on-link: true

Configuring source routing

Route tables can be added to particular interfaces to allow routing between two networks:

In the example below, ens3 is on the 192.168.3.0/24 network and ens5 is on the 192.168.5.0/24 network. This enables clients on either network to connect to the other and allow the response to come from the correct interface.

Furthermore, the default route is still assigned to ens5 allowing any other traffic to go through it.

network:
    version: 2
    renderer: networkd
    ethernets:
        ens3:
            addresses:
             - 192.168.3.30/24
            dhcp4: no
            routes:
             - to: 192.168.3.0/24
                 via: 192.168.3.1
                 table: 101
            routing-policy:
             - from: 192.168.3.0/24
                 table: 101
        ens5:
            addresses:
             - 192.168.5.24/24
            dhcp4: no
            gateway4: 192.168.5.1
            routes:
             - to: 192.168.5.0/24
                 via: 192.168.5.1
                 table: 102
            routing-policy:
            - from: 192.168.5.0/24
                table: 102

Configuring a loopback interface

Networkd does not allow creating new loopback devices, but a user can add new addresses to the standard loopback interface, lo, in order to have it considered a valid address on the machine as well as for custom routing:

network:
    version: 2
    renderer: networkd
    ethernets:
        lo:
            match:
                name: lo
            addresses: [ 7.7.7.7/32 ]

Integration with a Windows DHCP Server

For networks where DHCP is provided by a Windows Server using the dhcp-identifier key allows for interoperability:

network:
    version: 2
    ethernets:
        enp3s0:
            dhcp4: yes
            dhcp-identifier: mac

Connecting an IP tunnel

Tunnels allow an administrator to extend networks across the Internet by configuring two endpoints that will connect a special tunnel interface and do the routing required. Netplan supports SIT, GRE, IP-in-IP (ipip, ipip6, ip6ip6), IP6GRE, VTI and VTI6 tunnels.

A common use of tunnels is to enable IPv6 connectivity on networks that only support IPv4. The example below show how such a tunnel might be configured.

Here, 1.1.1.1 is the client’s own IP address; 2.2.2.2 is the remote server’s IPv4 address, “2001:dead:beef::2/64” is the client’s IPv6 address as defined by the tunnel, and “2001:dead:beef::1” is the remote server’s IPv6 address.

Finally, “2001:cafe:face::1/64” is an address for the client within the routed IPv6 prefix:

network:
    version: 2
    ethernets:
        eth0:
            addresses:
                - 1.1.1.1/24
                - "2001:cafe:face::1/64"
            gateway4: 1.1.1.254
    tunnels:
        he-ipv6:
            mode: sit
            remote: 2.2.2.2
            local: 1.1.1.1
            addresses:
                - "2001:dead:beef::2/64"
            gateway6: "2001:dead:beef::1"

Configuring SR-IOV Virtual Functions

For SR-IOV network cards, it is possible to dynamically allocate Virtual Function interfaces for every configured Physical Function. In netplan, a VF is defined by having a link: property pointing to the parent PF.

network:
    version: 2
    ethernets:
        eno1:
            mtu: 9000
        enp1s16f1:
            link: eno1
            addresses : [ "10.15.98.25/24" ]
        vf1:
            match:
                name: enp1s16f[2-3]
            link: eno1
            addresses : [ "10.15.99.25/24" ]