Create a systemd SMB mount on Debian Linux

Recently while I was working in my homelab I came across the need to mount some SMB shares to my LXC containers. The shares needed to persist through reboots as well, and I wanted to create a systemd unit to accomplish these tasks.

1. Install cifs-utils via apt:

   apt install cifs-utils -y

2. Next we need to create a set of credentials for the CIFS share to use:

   nano /root/.cifs_credentials

   username=usernamehere
   password=insertpasswordhere

3. Create a directory to mount your CIFS share on:

   mkdir -p /mnt/exampledir

4. Identify the id of the user and group of your currently logged in user. In my case I was logged in as root.

   id -u root && id -g root

   Save the id from this command to be used in the next step.

5. Create the systemd unit:

   nano /etc/systemd/system/mnt-media.mount

6. Insert the following into the new .mount file:

   [Unit]
   Description=Media Server files
   Requires=network-online.target
   After=network-online.target
   
   [Mount]
   What=//192.168.0.1/media/
   Where=/mnt/media
   Options=credentials=/root/.cifs_credentials,uid=0,gid=0
   Type=cifs
   
   [Install]
   WantedBy=multi-user.target

7. Enable systemd-networkd-wait-online. This is a oneshot systemd service that waits for the network to be configured. Without this enabled, our new systemd service will fail to run on server boot up.

   sudo systemctl enable systemd-networkd-wait-online.service

8. Enable the new systemd service:

   systemctl enable mnt-media.mount

9. Reboot your server for changes to take effect. If you experience any issues, check the journalctl logs.