External IPv6 connectivity for incus container

[candlerb]

I have an M3 Pro Macbook Pro, running macOS 14.7.3. I installed colima and created an incus container:

brew install colima
brew services start colima
colima start --runtime=incus
incus launch images:ubuntu/24.04/cloud first

This works. However, I find that the container and the Colima VM don't have external IPv6 connectivity, even though the Mac itself does. (More details below)

I see that the colima VM has not configured IPv6 on its eth0 uplink. I also notice that its IPv4 is 192.168.5.1, but there is no corresponding interface shown by ifconfig on the Mac. I found the 192.168.5 network listed in ~/.lima/_config/networks.yaml but there's no IPv6 there.

Is there anything I need to do to enable IPv6, or is this a limitation of the macOS virtualization framework, lima and/or colima?

Thanks in advance... Brian.

---

View from the container:

brian@Brians-MacBook-M3-Pro ~ % incus shell first
root@first:~# ping -c3 2001:4860:4860::8888
PING 2001:4860:4860::8888 (2001:4860:4860::8888) 56 data bytes
From fd42:b1f:8556:5c1d::1 icmp_seq=1 Destination unreachable: No route
From fd42:b1f:8556:5c1d::1 icmp_seq=2 Destination unreachable: No route
From fd42:b1f:8556:5c1d::1 icmp_seq=3 Destination unreachable: No route

--- 2001:4860:4860::8888 ping statistics ---
3 packets transmitted, 0 received, +3 errors, 100% packet loss, time 2073ms

root@first:~# ip -6 n
fd42:b1f:8556:5c1d::1 dev eth0 lladdr 00:16:3e:62:1e:c2 router STALE
fe80::216:3eff:fe62:1ec2 dev eth0 lladdr 00:16:3e:62:1e:c2 router DELAY
root@first:~# ip -6 a
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 state UNKNOWN qlen 1000
    inet6 ::1/128 scope host
       valid_lft forever preferred_lft forever
4: eth0@if5: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 state UP qlen 1000
    inet6 fd42:b1f:8556:5c1d:216:3eff:fe18:1401/64 scope global mngtmpaddr noprefixroute
       valid_lft forever preferred_lft forever
    inet6 fe80::216:3eff:fe18:1401/64 scope link
       valid_lft forever preferred_lft forever
root@first:~# ip -6 r
fd42:b1f:8556:5c1d::/64 dev eth0 proto ra metric 100 mtu 1500 hoplimit 64 pref medium
fe80::/64 dev eth0 proto kernel metric 256 pref medium
default via fe80::216:3eff:fe62:1ec2 dev eth0 proto ra metric 100 expires 1705sec mtu 1500 hoplimit 64 pref medium
root@first:~#

View from the colima VM:

brian@Brians-MacBook-M3-Pro ~ % colima ssh
brian@colima:/Users/brian$ ip a
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
       valid_lft forever preferred_lft forever
    inet6 ::1/128 scope host noprefixroute
       valid_lft forever preferred_lft forever
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UP group default qlen 1000
    link/ether 52:55:55:00:ad:4d brd ff:ff:ff:ff:ff:ff
    inet 192.168.5.1/24 metric 200 brd 192.168.5.255 scope global dynamic eth0
       valid_lft 2298sec preferred_lft 2298sec
    inet6 fe80::5055:55ff:fe00:ad4d/64 scope link
       valid_lft forever preferred_lft forever
3: incusbr0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default qlen 1000
    link/ether 00:16:3e:62:1e:c2 brd ff:ff:ff:ff:ff:ff
    inet 192.100.0.1/24 scope global incusbr0
       valid_lft forever preferred_lft forever
    inet6 fd42:b1f:8556:5c1d::1/64 scope global
       valid_lft forever preferred_lft forever
    inet6 fe80::216:3eff:fe62:1ec2/64 scope link
       valid_lft forever preferred_lft forever
5: vethdd00cf43@if4: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue master incusbr0 state UP group default qlen 1000
    link/ether 6a:e4:30:ce:4f:16 brd ff:ff:ff:ff:ff:ff link-netnsid 0
brian@colima:/Users/brian$ ip -6 r
fd42:b1f:8556:5c1d::/64 dev incusbr0 proto kernel metric 256 pref medium
fe80::/64 dev eth0 proto kernel metric 256 pref medium
fe80::/64 dev incusbr0 proto kernel metric 256 pref medium

brian@colima:/Users/brian$ sudo cat /etc/netplan/50-cloud-init.yaml
network:
  version: 2
  ethernets:
    eth0:
      match:
        macaddress: "52:55:55:00:ad:4d"
      nameservers:
        addresses:
        - 192.168.5.2
      dhcp-identifier: "mac"
      dhcp4: true
      dhcp4-overrides:
        route-metric: 200
      set-name: "eth0"

View from the Mac:

brian@Brians-MacBook-M3-Pro ~ % colima version
colima version 0.8.1
git commit: 96598cc5b64e5e9e1e64891642b91edc8ac49d16

runtime: incus
arch: aarch64
Client version: 6.6
Server version: 6.8

brian@Brians-MacBook-M3-Pro ~ % incus network show incusbr0
config:
  ipv4.address: 192.100.0.1/24
  ipv4.nat: "true"
  ipv6.address: fd42:b1f:8556:5c1d::1/64
  ipv6.nat: "true"
description: ""
name: incusbr0
type: bridge
used_by:
- /1.0/instances/first
- /1.0/profiles/default
managed: true
status: Created
locations:
- none
project: default

[abiosoft]

Is there anything I need to do to enable IPv6, or is this a limitation of the macOS virtualization framework, lima and/or colima?

It is indeed a limitation of Lima which is due to a limitation of the networking options available IIRC.
Both macOS virtualization framework and vmnet (used with Qemu) support only ipv4.