IIssues

Using Cloudinit and Netplan with IP’s on a different Network and Gateway

  • byJordan
  • May 18, 2023
  • 2 minute read

If you’ve ever had to utilize a hosting provider that offers the option to buy extra IPs or failover IP addresses, you may have observed instances where these IPs shared the same gateway as your original IPs, rather than being part of the additional IP network.

Here are some of the providers I’m aware of that require this.

  • OVH
  • SoYouStart

The problem is when you use Cloudinit to deploy your VM’s on Ubuntu which uses netplan and unfortunately, there isn’t a method to configure netplan through Cloudinit to use a gateway that isn’t on the same network as the IP address.

I’m using Proxmox, and although you can create a custom network configuration for netplan.yml and deploy it as a snippet via Cloudinit. This isn’t ideal.

Canonical looks to have fixed the bug this year (2023) in January https://github.com/canonical/cloud-init/pull/1931

However, that most likely relates to the new Ubuntu LTS. I’ve tested this within Ubuntu 20.04, and the appropriate config is in place. Here’s the generated /etc/netplan/50-cloud-init.yaml

root@srv01:~# cat /etc/netplan/50-cloud-init.yaml
# This file is generated from information provided by the datasource.  Changes
# to it will not persist across an instance reboot.  To disable cloud-init's
# network configuration capabilities, write a file
# /etc/cloud/cloud.cfg.d/99-disable-network-config.cfg with the following:
# network: {config: disabled}
network:
    version: 2
    ethernets:
        eth0:
            addresses:
            - 147.135.0.0/24
            match:
                macaddress: 02:00:00:79:e4:73
            nameservers:
                addresses:
                - 213.186.33.99
                search:
                - domain.com
            routes:
            -   on-link: true
                to: default
                via: 15.0.0.254
            set-name: eth0
        eth1:
            dhcp4: true
            match:
                macaddress: 8a:ca:d3:4d:c9:28
            set-name: eth1
    Reddit – Dive into anything
    www.reddit.com
    BUG: No routing in VM with cloud init (ubuntu 18.x – 19.4) | Proxmox Support Forum
    It´s possible a bug in the network setting from proxmox to VMs with cloud-init and ubuntu. I have see many forum entries about the same problemas! The big…
    forum.proxmox.com

    https://linuxconfig.org/how-to-add-static-route-with-netplan-on-ubuntu-22-04-jammy-jellyfish-linux

    UUncategorized

    So You Start netplan Configuration for Additional IP’s

    • byJordan
    • June 11, 2020
    • 1 minute read

    This took way too long to figure out and it’s my own fault as I do have a good understanding of networking.

    When you order additional IP’s from So You Start, you’re usually giving IP’s in a different range the main IP address of your server. This might confuse some because of how traditional networking states you have to be in the same subnet as your gateway.

    This causes problems for deploying virtual machines when using Xen and Ubuntu 18 as it has moved over to netplan. The problem lies in the fact you shouldn’t be able to reach your gateway out of your subnet.

    So you have to do the following so that netplan is able to understand how to add the gateway properly.

    Go

    Here’s the wonderful thread it came from

    https://askubuntu.com/questions/1062406/ubuntu-18-04-server-vps-on-failover-ip-ovh