I write openvpn config which download from my provider, in configuration with service.openvpn.server. I try to run systemctl start openvpn_myvpn.service and it is always failed with Start request repeated too quickly by journalctl.
I have tried to run openvpn --config myvpn_config, it is successful.
I have fixed it.
The repeated request can be solved by config systemd.extraConfig with DefaultStartLimitIntervalSec and DefaultStartLimitBurst.
But it is not the realy problem. The main reason is my vpn config which contains space before each line(because of nix multiple-line-string doesn’t remove space beginning from each line).