Mount NAS Directories to PVE and LXC

Mounting a folder from your NAS to your Proxmox (PVE) host so that your LXCs can access it is a common and very useful setup. Here's a comprehensive guide, covering the most common scenarios and best practices.

[!note] Understanding the Flow:

1. NAS Share: Your NAS needs to have a share configured (e.g., SMB/CIFS or NFS). NFS is generally preferred for Linux-based systems like Proxmox due to better POSIX permissions handling and performance, but SMB/CIFS can also work.
2. PVE Host Mount: You'll mount the NAS share onto your Proxmox host. This makes the NAS content directly accessible by the PVE kernel.
3. LXC Bind Mount: You'll then "bind mount" a specific directory from the PVE host into your LXC container. This effectively makes the NAS content appear inside the LXC.

Step-by-Step Guide

Let's assume your NAS share is //192.168.1.100/myshare (SMB) or 192.168.1.100:/myshare (NFS).

Option 1: Using NFS (Recommended for Linux Systems)

NFS is generally more robust and performs better with Linux.

Part 1: Configure NAS (NFS)

1. Enable NFS Service: On your NAS (Synology, QNAP, TrueNAS, etc.), ensure the NFS service is enabled.
2. Create Share: Create the folder/share you want to export (e.g., myshare).
3. Set NFS Permissions:

• Host: Add the IP address of your Proxmox host (e.g., 192.168.1.50) to the allowed hosts for this share. You might see options like * for all hosts (less secure) or specific subnet masks.
• Root Squash/No Root Squash: Be careful with this.
• no_root_squash: Root on the client (Proxmox) will be treated as root on the NFS server. This provides full control but can be a security risk if the Proxmox host is compromised.
• root_squash (default): Root on the client will be mapped to an anonymous user/group (often nobody:nogroup) on the NFS server. This is safer but might cause permission issues if your LXC processes need root-level access to the files.
• Permissions: Set read/write (RW) permissions if your LXC needs to write to the share.

Part 2: Mount on Proxmox Host (NFS)

1. Install NFS Client:

apt update
apt install nfs-common

2. Create Mount Point on PVE: Choose a location on your Proxmox host to mount the NAS share. A common place is /mnt/nas/<share_name>.

mkdir -p /mnt/nas/myshare

3. Test Mount:

mount -t nfs 192.168.1.100:/myshare /mnt/nas/myshare

• Common Options:
• _netdev: Ensures the network is up before attempting to mount (important for /etc/fstab).
• auto: Allows mounting at boot.
• sync or async: async (default) can improve performance but risks data loss on crashes. sync is safer but slower.
• hard or soft: hard makes the client retry indefinitely on errors (can hang processes). soft makes it return an error after a timeout. soft,intr allows processes to be interrupted. hard,intr is often a good balance.
• nolock: If you encounter issues (less common with modern NFSv4).
• vers=3 or vers=4: Specify NFS version if needed. Most modern setups use NFSv4.

For example:

mount -t nfs 192.168.1.100:/myshare /mnt/nas/myshare -o defaults,hard,intr,_netdev

4. Verify Mount:

df -h /mnt/nas/myshare
ls -l /mnt/nas/myshare

You should see the contents of your NAS share.

5. Make Mount Permanent (Add to /etc/fstab):

echo "192.168.1.100:/myshare /mnt/nas/myshare nfs defaults,hard,intr,_netdev 0 0" >> /etc/fstab

• Important: Always test the manual mount command first.
• After adding to fstab, run mount -a to test if it mounts correctly before rebooting or using systemctl deamon-reload to make the changes effective.

Option 2: Using SMB/CIFS

SMB/CIFS is more common for Windows environments but works fine.

Part 1: Configure NAS (SMB/CIFS)

1. Enable SMB/CIFS Service: On your NAS, ensure the SMB/CIFS service is enabled.
2. Create Share: Create the folder/share you want to export (e.g., myshare).
3. User/Permissions: Create a dedicated user on the NAS (e.g., pve_user) with read/write permissions to this specific share. This is crucial for mounting from Linux. Set a strong password.

Part 2: Mount on Proxmox Host (SMB/CIFS)

1. Install CIFS Utilities:

apt update
apt install cifs-utils

2. Create Mount Point on PVE:

mkdir -p /mnt/nas/myshare

3. Store Credentials (Securely): It's best not to put credentials directly in /etc/fstab. Create a credentials file:

mkdir -p /etc/samba
nano /etc/samba/credentials_myshare

Add these two lines:

username=pve_user
password=YourStrongPasswordHere

Secure the file:

chmod 600 /etc/samba/credentials_myshare

4. Test Mount:

mount -t cifs //192.168.1.100/myshare /mnt/nas/myshare -o credentials=/etc/samba/credentials_myshare,uid=0,gid=0,forceuid,forcegid,file_mode=0644,dir_mode=0755

• uid, gid, forceuid, forcegid: These options are crucial for controlling how permissions are mapped from SMB to Linux. uid=0, gid=0 (root) is a common choice for initial setup, but you might want to map to a specific user/group ID on your Proxmox host that also exists in your LXC.
• file_mode, dir_mode: Sets default permissions for new files/directories created via the mount.
• Guest access: If your NAS allows guest access, you might use guest or username=guest,password= instead of a credentials file.

5. Verify Mount:

df -h /mnt/nas/myshare
ls -l /mnt/nas/myshare

6. Make Mount Permanent (Add to /etc/fstab):

echo "//192.168.1.100/myshare /mnt/nas/myshare cifs credentials=/etc/samba/credentials_myshare,uid=0,gid=0,forceuid,forcegid,file_mode=0644,dir_mode=0755,_netdev 0 0" >> /etc/fstab

• Run mount -a to test.

Part 3: Bind Mount into LXC

Once the NAS share is successfully mounted on your PVE host, you can bind mount it into your LXC.

1. Identify LXC ID: Get the ID of your LXC (e.g., 101). You can find this in the Proxmox web UI.

2. Run the following command:

pct set 101 -mp0 /host/dir,mp=/container/mount/point

To unmount simply run

pct set 101

3. Restart LXC: For the bind mount to take effect, you must restart the LXC.

pct stop 101
pct start 101

Or through the Proxmox web UI.

4. Verify Inside LXC: After the LXC restarts, access its console again and verify the mount:

df -h /media/nas_data
ls -l /media/nas_data

You should now see the contents of your NAS share within the LXC at /media/nas_data.

[!note] Don't forget to update permissions on your NAS side otherwise the LXC still won't be able to access files.