LXC Virtual Machine without internet access

Question

I am trying out my hands with the LXC for the first time. I need a 22.04 VM that can have access to the internet. My host is a fresh installation of Ubuntu Server 24.04. My local physical LAN is eno33.

I first used neplan to set up a bridge:

network:
    version: 2
    renderer: networkd
    ethernets:
        eno33:
           dhcp4: false
           dhcp6: false
#           addresses:
#               - 172.16.56.26/23
#           routes:
#           - to: default
#             via: 172.16.57.253
#           nameservers:
#           addresses: [172.16.99.7,172.16.99.8]

    bridges:
      br0:
          interfaces: [eno33]
          addresses: [172.16.56.26/23]
          routes:
           - to: default
             via: 172.16.57.253
          nameservers:
            addresses: [172.16.99.7,172.16.99.8]
          parameters:
                stp: true
                forward-delay: 4

apetros@host:~$ ip r
default via 172.16.57.253 dev br0 proto static
172.16.56.0/23 dev br0 proto kernel scope link src 172.16.56.26
apetros@host:~$ 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: eno33: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq master br0 state UP group default qlen 1000
    link/ether e4:3d:1a:62:13:16 brd ff:ff:ff:ff:ff:ff
    altname enp99s0f0
8: br0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default qlen 1000
    link/ether ae:f4:ec:9a:d1:c1 brd ff:ff:ff:ff:ff:ff
    inet 172.16.56.26/23 brd 172.16.57.255 scope global br0
       valid_lft forever preferred_lft forever
    inet6 fe80::acf4:ecff:fe9a:d1c1/64 scope link
       valid_lft forever preferred_lft forever

I then create the VM:

apetros@host:~$ lxc init ubuntu:22.04 u1 --vm
apetros@host:~$ lxc config device add u1 eth0 nic nictype=bridged parent=br0 name=eth0
apetros@host:~$ lxc restart u1
apetros@host:~$ lxc list
+----------+---------+------+------+-----------------+-----------+
|   NAME   |  STATE  | IPV4 | IPV6 |      TYPE       | SNAPSHOTS |
+----------+---------+------+------+-----------------+-----------+
| u1       | RUNNING |      |      | VIRTUAL-MACHINE | 0         |
+----------+---------+------+------+-----------------+-----------+

As you see, no ip is given to the u1. Seeing more details:

apetros@spslab:~$ lxc config show --expanded u1
architecture: x86_64
config:
  image.architecture: amd64
  image.description: ubuntu 22.04 LTS amd64 (release) (20241004)
  image.label: release
  image.os: ubuntu
  image.release: jammy
  image.serial: "20241004"
  image.type: disk-kvm.img
  image.version: "22.04"
  volatile.base_image: ab8380e088c0e3e2d88b7a32224de91723c2fe455f151db61c36eb23900f69cd
  volatile.cloud-init.instance-id: 758bffe1-74e5-4ab9-a74c-e7da29a93696
  volatile.eth0.host_name: tap3add331f
  volatile.eth0.hwaddr: 00:16:3e:17:fb:e6
  volatile.last_state.power: RUNNING
  volatile.uuid: 9c04c042-b026-44da-a081-06ecbe91f1f5
  volatile.uuid.generation: 9c04c042-b026-44da-a081-06ecbe91f1f5
  volatile.vsock_id: "1271446946"
devices:
  eth0:
    name: eth0
    nictype: bridged
    parent: br0
    type: nic
  root:
    path: /
    pool: default
    type: disk
ephemeral: false
profiles:
- default
stateful: false
description: ""

A simple:

lxc exec u1 -- apt update

Shows the VM has no internet access. Doing:

apetros@host:~$ lxc exec u1 -- bash
root@u1:~# 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
       valid_lft forever preferred_lft forever
2: enp5s0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq state UP group default qlen 1000
    link/ether 00:16:3e:17:fb:e6 brd ff:ff:ff:ff:ff:ff
    inet6 fe80::216:3eff:fe17:fbe6/64 scope link
       valid_lft forever preferred_lft forever

So, eth0 is not available inside u1 and only enp5s0 is there.

Any ideas what to do?

Answer 1

this set up ovn network for your containers

apt install ovn-host ovn-central

ovs-vsctl set open_vswitch . external_ids:ovn-remote=unix:/var/run/ovn/ovnsb_db.sock external_ids:ovn-encap-type=geneve external_ids:ovn-encap-ip=127.0.0.1
lxc network set br0 ipv4.dhcp.ranges=<IP_range> ipv4.ovn.ranges=<IP_range>
lxc network create ovntest --type=ovn network=br0
lxc init ubuntu:22.04 <instance_name>
lxc config device override <instance_name> eth0 network=ovntest
lxc start <instance_name>