No support for interface labels

[Maciej Dems]

In the old /etc/network/interfaces I could define a virtual interface:

    auto eth0
    iface eth0 inet static
        address aaa.aaa.aaa.aaa
        netmask 255.255.255.0
        gateway aaa.aaa.aaa.1

    auto eth0:0
    iface eth0:0 inet static
        address bbb.bbb.bbb.bbb
        netmask 255.255.255.0

This is not possible to achieve with the netplan. The only exisiting posibilities are either to create a VLAN, which may be not an option in some networks where you have no access to other hosts, or to define both addresses for one interface:

    network:
      version: 2
      renderer: networkd
      ethernets:
        eth0:
          addresses: [aaa.aaa.aaa.aaa/24, bbb.bbb.bbb/24]
          gateway4: aaa.aaa.aaa.1

This solution is not optimal either, because configuring iptables or some services may require specific interface name for a single network.

It should be possible to add the same physical interfaces with different networks and different alias names.

[Robert Sander (gurubert)]

This is called an interface label, the iproute2 syntax is as follows:

ip address add bbb.bbb.bbb.bbb/24 dev eth0 label eth0:0

netplan should support this configuration.

[Jamie Murphy (itjamie)]

Is there any plan to implement this?

[sascha arthur (sarthur)]

yes please also need it :((

[Volker (skydiablo)]

+1

[Florian Faltermeier (florianfa)]

+1

[Alexey Zilber (alexeyzilber)]

+1 Also, why is this a "Wishlist"? This is BASIC FUNCTIONALITY that has been in linux since the 1990's! This is a functional defect.

[Jamie Murphy (itjamie)]

+1. Its insane that a configuration option thats been around for years was skipped.

[Peter Lambrechtsen (plambrechtsen)]

+1 I have also stumbled onto this via various searches.

It seems on my host the secondary IP address does get added, but I can't see it anywhere via ifconfig.

cat /etc/netplan/01-default.yaml
network:
  version: 2
  renderer: networkd
  ethernets:
    eth0:
      dhcp4: no
      addresses:
        - 192.168.1.150/24
        - 192.168.2.150/24
      gateway4: 192.168.1.251
      nameservers:
        addresses: [192.168.1.254]

the ifconfig gives me

ifconfig
eth0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
        inet 192.168.1.150 netmask 255.255.255.0 broadcast 192.168.1.255
        RX packets 205 bytes 18287 (18.2 KB)
        RX errors 0 dropped 42 overruns 0 frame 0
        TX packets 81 bytes 11947 (11.9 KB)
        TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
        device interrupt 20

But doesn't list the second ip address, but "ip address" does.

ip address
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq state UP group default qlen 1000
    inet 192.168.1.150/24 brd 192.168.1.255 scope global eth0
       valid_lft forever preferred_lft forever
    inet 192.168.2.150/24 brd 192.168.2.255 scope global eth0
       valid_lft forever preferred_lft forever

it would be ideal if it turned up as a secondary IP address ie eth0:0 or eth0:1 etc..

[Eric stumbo (digikin)]

+1

[dimi (dimitrios)]

+1
thought i learn netplan on my new server and use a second IP, project ended here

[Federico Alves (h-sales)]

I am affected by this bug.

[Robert Sander (gurubert)]

BTW: ifconfig is deprecated for at least 10 years now: https://lists.debian.org/debian-devel/2009/03/msg00780.html

Please start using "ip".

[Jamie Murphy (itjamie)]

its not just ifconfig that uses interface labels. many programs use them for mapping which ip they bind to.

[Lukas Märdian (slyon)]

We have that as an item on the current netplan development backlog.

[Lukas Märdian (slyon)]

As a clarification on this topic:

We will be implementing ip address labels, as defined by iproute2's "ip address [...] label eth0:XXX" command (man ip-address). Not to be confused with ifconfig's legacy method of using aliased or virtual interfaces, which behave almost like a real interface.

The newer 'ip' utility does not use the legacy concept of alias interfaces. However, it supports assigning arbitrary names to the interfaces, called 'labels'. Both methods have in common that they allow to assign multiple IP addresses to an interface, which can be referenced by name.

[Lukas Märdian (slyon)]

Support for IP address labels has been merged upstream and will be part of the next netplan.io release: https://github.com/CanonicalLtd/netplan/pull/89

[Lukas Märdian (slyon)]

netplan 0.100 has now been released, including this feature.

[Bruno Criado (brunocriado)]

How I can see the current version of netplan that I'm using since that `netplan info` doesn't bring version number and is it already available on Ubuntu 20.04.1 (server)?

[Lukas Märdian (slyon)]

Hi Bruno, you can call `dpkg -l | grep netplan` to see the installed version. Netplan 0.100 is available in Ubuntu Focal 20.04 LTS.

[Jessica Litwin (bolognese)]

Any chance of a backport to bionic?

[Lukas Märdian (slyon)]

Hi Jessica, there is currently no plan to backport Netplan >= 0.100 to Bionic. If you need this urgently, please open a new bug report explaining your rationale.