I am using discovery to deploy hosts on Hetzner Cloud. The gateway is outside of the ip subnet so the installer fails to get network and fails to download kickstart file.
Hetzner’s support recommends to use
route add 172.31.1.1/32 dev ens3
How can I add this to the deployment process?
You either fix the DHCP to return proper gateway IP address or else you need to use manual network credentials. Depending on your OS (Debian, Redhat) templates will make sure it renders down to kernel command line installer can pick up and configure from.
E.g. for redhat systems this would be the