If FQDN is number, cloud-config.service fails

[EHPS-Oliver]

Bug report

When the fqdn is a number, python treats it as a literal number 123 instead of "123". This causes the following issue

[    7.913699] cloud-init[652]:   File "/usr/lib/python3/dist-packages/cloudinit/util.py", line 1207, in get_hostname_fqdn
[    7.914904] cloud-init[652]:     hostname = get_cfg_option_str(cfg, "hostname", fqdn.split(".")[0])
[    7.915941] cloud-init[652]:                                                    ^^^^^^^^^^
[    7.916898] cloud-init[652]: AttributeError: 'int' object has no attribute 'split'

Steps to reproduce the problem

(Using proxmox with cloud init guests.)

1. Set vm "name" to a number
2. Start vm
3. "Failed to start cloud-init.service"

Environment details

• Cloud-init v. 24.4-0ubuntu1~24.04.2
• On proxmox

cloud-init logs

Can't currently log in to check those - troubleshooting another issue preventing me from logging in :)