NFS Share from a Synology NAS in an Unprivileged LXC Container

[initB10r]

Hello everyone,

After my QNAP NAS failed, I recently switched to a Synology NAS and now I’m facing an issue where I need your help.

I’ve set up a test share on my Synology NAS as follows:



I mounted this share on my Proxmox host like this:



On the Proxmox host, I can access the share at /mnt/pve/NAS_A without any issues. I can create, modify files and directories, and use chown to freely change the owner and group.

However, when I start an unprivileged LXC container with the following configuration, I’m unable to access the directory /share/DockerNew:

arch: amd64
cores: 1
features: keyctl=1,nesting=1
hostname: test
memory: 512
mp0: /mnt/pve/NAS_A,mp=/share/DockerNew
net0: name=eth0,bridge=vmbr0,firewall=1,hwaddr=BC:24:11:E7:85:48,ip=dhcp,type=veth
ostype: debian
rootfs: Data:subvol-107-disk-0,size=8G
swap: 512
unprivileged: 1
lxc.idmap: u 0 100000 1000
lxc.idmap: g 0 100000 1000
lxc.idmap: u 1000 1000 1
lxc.idmap: g 1000 1000 1
lxc.idmap: u 1001 101001 64535
lxc.idmap: g 1001 101001 64535

Running ls -l on /share inside the LXC container gives me:

root@test:/share# ls -l 
total 0 
drwxrwxrwx 1 schneckenDocker schneckenDocker 114 Jan 27 14:45 DockerNew 
root@test:/share# cd DockerNew/ 
-bash: cd: DockerNew/: Permission denied

On the Proxmox host, the output is:

root@schneckenProxmox:~# ls -l /mnt/pve/ 
drwxrwxrwx 1 schneckenDocker schneckenDocker 114 Jan 27 15:45 NAS_A 

root@schneckenProxmox:~# cd /mnt/pve/NAS_A 
root@schneckenProxmox:/mnt/pve/NAS_A# ls -l 
total 4 
drwxrwxrwx 1 schneckenDocker schneckenDocker 0 Jan 27 15:04 images 
-rw-r--r-- 1 schneckenDocker schneckenDocker 0 Jan 27 15:32 NfsA_1000 
-rw-r--r-- 1 schneckenDocker schneckenDocker 2 Jan 27 15:45 NfsA_100000 
-rw-r--r-- 1 schneckenDocker schneckenDocker 0 Jan 27 15:32 NfsA_root 
drwxrwxrwx 1 schneckenDocker schneckenDocker 0 Jan 27 15:04 snippets 
-rwxrwxrwx 1 schneckenDocker schneckenDocker 0 Jan 27 15:45 winA.txt

The user schneckenDocker (ID 1000) exists on the Synology NAS, the Proxmox host, and inside the LXC container. Despite this, I receive a Permission denied error when trying to access the directory in the container.

Does anyone know why I cannot access the share within the LXC container? I never had this issue with my previous QNAP NAS.

Thank you so much for your support!

Best regards,
Marc

 

[nodau]

If there haven't been any changes lxc with nfs access only works with privileged conainers.


My Synology nfs mount looks like this:


Also with unprivileged lxc you can neither activate nfs nor smb:


So if you want nfs in lxc you need to make a priviliged one.

 

[initB10r]

Thank you for your reply! However, I can’t understand this, as my original LXC container with a Docker installation was able to access an NFS share from QNAP without any issues.

Here are the settings from the QNAP:



It must be possible to make this work with the NFS from Synology as well.

Does anyone have any ideas?