Cloudinit issue with legacy CentOS Stream 8

i assume you using the same userdata from this post?

try a new simple userdata template like

#cloud-config
hostname: <%= @host.name %>
fqdn: <%= @host %>
manage_etc_hosts: true
users: {}
runcmd:
- touch ~/test.txt

phone_home:
  url: <%= foreman_url('built') %>
  post: []
tries: 10
EOF