Nixos-generators configuration in finish azure image

Help
1

Using nixos-generators to building an azure image with: nixos-generator -f azure -c ./configuration.nix
where configuration.nix is my wanted configuration in the finish azure image. But after build and boot up the azure vm have the configuration (/etc/nixos/configuration.nix) from https://github.com/NixOS/nixpkgs/blob/0dfaae9bea51f9e1e4dc7ea69977bd89fb23fd1f/nixos/modules/virtualisation/azure-config-user.nix

Have I misunderstood the -c argument. Is this for build instead of configuration for finish image?

2

Think I understand now. The configuration you give with the -c arg is the config in get in finish image. But it is not added to /etc/nixos/configuration.nix