👩‍💻 Documentation Request: clarify netplan for alternate ips and replacing cloud init

[Nicolas-Innocent]

Summary

the documentation for ubuntu (netplan) is very lacking

Why is it needed?

(this is written with a 24.04 ubuntu dedibox installed this week)

in the case we use ip-redirects, the default netplan needs to be replaced, this means
1/ disabling cloud-init network by creating the /etc/cloud/cloud.cfg.d/99-disable-network-config.cfg file with content :
network: {config: disabled}

2/ copying and disabling the existing netplan
cp /etc/netplan/50-cloud-init.yaml /etc/netplan/01-myplan.yaml
mv /etc/netplan/50-cloud-init.yaml /etc/netplan/50-cloud-init.yaml-backup

3/ replacing the dhcp sections with the customer section, so

enp5s0:
      critical: true
      nameservers:
        addresses:
        - 51.159.69.156
        - 51.159.69.162
      dhcp-identifier: "mac"
      dhcp4: true

becomes

enp5s0:
            critical: true
            dhcp-identifier: mac
            dhcp4: false
            dhcp6: false
            addresses:
                - 51.111.222.333/24     # Server Main IP (/24)
                - 212.111.222.333/32   # Alternate IPs / IP Redirects (/32)
                - 212.111.222.334/32
                - 212.111.222.335/32
            routes:
                - to: 0.0.0.0/0
                  via: 62.210.0.1
                  metric: 1
                  on-link: true
            nameservers:
                addresses:
                  - 51.159.69.156
                  - 51.159.69.162

4/ disable dhcp herited routing for secondary network cards
so

enp6s0:
      dhcp4: true

becomes

enp6s0:
    dhcp4: true
            dhcp4-overrides:
                use-routes: false
            routes:
                - to: 10.88.0.0/13       #use appropriate ip/gateway from the dhcp
                  via: 10.89.23.129

6/ do netplan try (and then netplan apply) and prey it works, or spend a while rewriting the file via the kvm/ip because any error WILL bork your configuration

Want to write this documentation yourself?

No

Related PR(s)

No response

(Optional) Scaleway Organization ID

No response

Email address

n.innocent@groupe-dasilva.com

[ofranc]

https://www.scaleway.com/en/docs/dedibox-ip-failover/how-to/configure-debian-ubuntu/