cloud-initramfs-dyn-netconf software package provides write a network interface file in /run for BOOTIF, you can install in your Debian 9 (Stretch) by running the commands given below on the terminal,
$ sudo apt-get update $ sudo apt-get install cloud-initramfs-dyn-netconf
cloud-initramfs-dyn-netconf is installed in your system.
Make ensure the cloud-initramfs-dyn-netconf package were installed using the commands given below,
$ sudo dpkg-query -l | grep cloud-initramfs-dyn-netconf *
You will get with cloud-initramfs-dyn-netconf package name, version, architecture and description in a table
| Distro | Debian 9 stretch |
| Section | Administration Utilities |
| Package | cloud-initramfs-dyn-netconf |
| Version | 0.18.debian5 |
| Description | write a network interface file in /run for BOOTIF |
| Sub Section | admin |