IPv6 addresses are lost in my VMs on Oracle Cloud, probability caused by the DHCP issue.

Here’s a quick fix I found that works, just enable dhcp6 in the /etc/netplan/50-cloud-init.yaml.

For instance:

network:
  version: 2
  ethernets:
    enp0s3:
      dhcp4: true
      match:
        macaddress: 00:00:00:xx:xx:xx
      set-name: enp0s3
      dhcp6: true

That’s it.

My previous solution seems not working anymore. Just have a record FYI:

1. For AMD machines

   sudo dhclient -6 ens3
   

2. For ARM machines

   sudo dhclient -6 enp0s3
   

ens3 or enp0s3 is the network interface set by default. Check the correct interface name with the ip addr command.