Fix lost IPv6 connectivity on old Debian Buster images when migrating to routed IP

On older Debian Buster images, the installed custom version of cloud-init may interfere with IPv6 connectivity when the instance transitions to using routed IP. To avoid this, you should install a newer version of cloud-init before the migration to routed IP. This procedure also recovers connectivity for an instance already using routed IP.

1. Install the new debian-stable PPA. The URL of the PPA may be configured to use the noble series. Replace noble with bionic in the URL.

   rm -f /etc/apt/sources.list.d/scaleway-ubuntu-stable-bionic.list
   add-apt-repository ppa:scaleway/debian-staging
   nano /etc/apt/sources.list.d/scaleway-ubuntu-debian-staging-noble.list
   

   In the file opened with nano, replace noble with bionic.
2. Install the new version of scaleway-ecosystem and cloud-init. It is important to clean the previous cloud-init data as the new version has a structure that may cause a failure at the next boot.

   apt update
   apt -y install scaleway-ecosystem cloud-init
   cloud-init clean
   

3. Reboot the Instance to apply the changes.

   reboot