Bridge with Netplan (For LXC) doesn't work

1

Hello,

I’m trying to do something that I already did in the past with ubuntu 16.x when it was using ifupdown.
I’m not really a Linux guy and for what I try to do if I could configure a LXC docker instead of a VM I would probably be able to save 90% on ram Ressource.

Anyway, so apparently in ubuntu 17.x they changed ifupdown for Netplan. I need to give to all my docker an IP in the same range of my host which in my case is the network 192.168.124.0/23

At first I tried to follow this guide how to configure the bridge interface and it didn’t work at all :
https://netplan.io/examples

The interfaces is showing up, but I lost all connection (I can’t ping internet, my local network, etc)

If some could help me with this problem, because I’m starting to become crazy :frowning:

This is the config file that I made for /etc/netplan/*.yaml

network:
  version: 2
  renderer: networkd
  ethernets:
    ens160:
      dhcp4: no
      dhcp6: no
  bridges:
      lxdr0:
        dhcp4: no
        interfaces: [ens160]
        addresses: [192.168.124.105/23]
        gateway4: 192.168.124.1
        nameservers:
          addresses: [8.8.8.8]
        parameters:
          stp: false
          forward-delay: 0

I have installed bridge-utils

If someone can help me figuring out why is not working

Just clarify I have all the required space in my original file

2

What init options did you use with lxd ? Did you specifiy to use your own bridge or the lxdbridge ? (and then preced to create this beidge?)

I have the same setup (less the bridge params) and it should be fine

3

For now It is not installed. Maybe that’s why it’s not working, not in my souvenir I didn’t need to have any lxd/lxc to configure a bridge.

With these settings when I enter “netplan apply” everything seems fine if I look to the ip configuration with the command “ip a”, but I’m not able to ping anything except myself.

Do I have to enable something like packet forwarding?

If it’s important I’m not on a barebone server, but in a VMware Esxi host. The Ubuntu installed is Ubuntu server with the cloud settings for management.( For example to change my hostname I had to enter something in the config file to not reset the hostname everytime I reboot)

4

Hi, one of mine server netplan config:

network:
ethernets:
    eno1:
        dhcp4: false
    eno2:
        addresses: []
        dhcp4: false
    eno3:
        addresses: []
        dhcp4: true
        optional: true
    eno4:
        addresses: []
        dhcp4: true
        optional: true
bridges:
    br0:
        interfaces: [eno1]
        dhcp4: false
        addresses: [IP/24]
        gateway4: GATEWAY IP
        nameservers:
            addresses:
            - DNS IP
            - DNS IP
            search: []
    br1:
        interfaces: [eno2]
        dhcp4: false
        addresses: [IP/16]
version: 2

netplan generate
netplan apply

As log as ip and nic name is good you shloud be all ok. 18.04 work by default, do not know 17.10 since it’s not LTS.

5

I’m not at work right now, but I will try it again in my homelab.

Really wierd, last time I tried it in my homelab I got an issue with all my network once I entered apply. My home router stopped working. I had to shutdown the VM and reset my home router.

It’s been 2 year’s that I didn’t really use Linux so I’m a bit out of my comfort zone (pretty funny because before working in IT I was a bit more knowledgeable about Linux then windows). I will try again with a fresh new VM, read a bit of documentation and see if I’m able to make it work.

Thanks for the responding, I will update later after I tried again.

6

There should be some option in VMware called Allow promiscuous or similar.
If it worked earlier without that, then disregard.

7

I had to enable promiscuous mode on the network adapter also there is a guide on vmware pubs here your bridge configuration is almost indentical to mine which works (on a VM on esxi)

8

Awsome!!!

It was my vswitch which refused promiscuous mode.
At first I tried to enable the option, but I was still not working until I remark that the changed has still not be made…

Really appreciated the help that you have provided. I had totally forget to look at my network on my hypervisor if the promiscuous mode was enabled or not.

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1 Like
9

Also check out https://www.claudiokuenzler.com/blog/551/network-problem-lxc-same-subnet-as-host-in-vmware, where the LXC inside VMware environments problem and solution was documented.