anchor.diff:            fi
   
             echo "obtaining SSH public host key..."
  -          curl -o /root/ssh_host_ecdsa_key.pub --retry-max-time 60 http://metadata/0.1/meta-data/attributes/ssh_host_ecdsa_key_pub
  +          $wget -O /root/ssh_host_ecdsa_key.pub http://metadata/0.1/meta-data/attributes/ssh_host_ecdsa_key_pub
             if [ $? -eq 0 -a -e /root/ssh_host_ecdsa_key.pub ]; then
                 mv -f /root/ssh_host_ecdsa_key.pub /etc/ssh/ssh_host_ecdsa_key.pub
                 echo "downloaded ssh_host_ecdsa_key.pub"
  
positive.code: 
    networking.usePredictableInterfaceNames = false;
  
    systemd.services.wait-metadata-online = {
      description = "Wait for GCE metadata server to become reachable";
      wantedBy = [ "network-online.target" ];
      before = [ "network-online.target" ];
      path = [ pkgs.netcat ];
      script = ''
        # wait for the metadata server to become available for up to 60 seconds
        for counter in {1..30}; do sleep 2 && nc -vzw 2 metadata 80 && break; done
      '';
      serviceConfig.Type = "oneshot";
      serviceConfig.RemainAfterExit = true;
    };
  
    systemd.services.fetch-ssh-keys =
      { description = "Fetch host keys and authorized_keys for root user";
  
  
negative.code:         '';
        serviceConfig.Type = "oneshot";
        serviceConfig.RemainAfterExit = true;
        serviceConfig.StandardError = "journal+console";
        serviceConfig.StandardOutput = "journal+console";
       };
  }
  