How to process files from a different computer?

Individual-Heart-719 · 24 July 2022 10:22

I’ve retried with an ext4 drive with no luck. The only thing different I’ve done from the guide is that instead of a bind mount I’ve mounted the drive directly to the /srv/nfs location.

s: server, c: client
s ❯ sudo mkdir -p /srv/nfs/V
s ❯ sudo chmod ugo+rwx /srv/nfs/V
s ❯ sudo umount /run/media/user/V
s ❯ lsblk -no UUID /dev/sdd1
61aea4de-aa02-4f6d-b77d-dc0b09eac2ca

s ❯ sudo blkid
/dev/sdd1: LABEL="V" UUID="61aea4de-aa02-4f6d-b77d-dc0b09eac2ca" BLOCK_SIZE="4096" TYPE="ext4" PARTUUID="823000c4-e3eb-434a-a5f9-009571ecd1c8"

s ❯ sudo cat /etc/systemd/system/srv-nfs-V.mount
[Unit]
Description=My shared partition

[Mount]
What=/dev/disk/by-uuid/61aea4de-aa02-4f6d-b77d-dc0b09eac2ca
Where=/srv/nfs/V
Type=nfs
Options=defaults,rw,noatime

[Install]
WantedBy=multi-user.target

s ❯ sudo cat /etc/systemd/system/srv-nfs-V.automount
[Unit]
Description=Automount shared partition
ConditionPathExists=/srv/nfs/V

[Automount]
Where=/srv/nfs/V
TimeoutIdleSec=10

[Install]
WantedBy=multi-user.target

s ❯ sudo systemctl enable --now srv-nfs-V.automount
s ❯ ls -l /srv/nfs/V
ls: cannot open directory '/srv/nfs/V': No such device
s ❯ sudo rm /etc/systemd/system/*mount
s ❯ sudo cat /etc/fstab
UUID=61aea4de-aa02-4f6d-b77d-dc0b09eac2ca /srv/nfs/V ext4 defaults,noatime 0 0
s ❯ sudo systemctl daemon-reload
s ❯ sudo mount -a
s ❯ ls -l /srv/nfs/V
total 24
s ❯ sudo ln -s /srv/nfs/V /run/media/user/V
s ❯ sudo cat /etc/exports
/srv/nfs            192.168.1.118(rw,sync,crossmnt,fsid=0)
/srv/nfs/V          192.168.1.118(rw,sync)

s ❯ sudo systemctl enable --now nfs-server.service

c ❯ sudo systemctl enable --now nfs-client.target
c ❯ sudo cat /etc/fstab
192.168.1.122:/nfs/V   /srv/nfs/V  nfs auto,x-systemd.automount,x-systemd.device-timeout=10,timeo=14,x-systemd.idle-timeout=1min 0 0
c ❯ sudo systemctl daemon-reload
c ❯ sudo mkdir -p /srv/nfs/V
c ❯ sudo mount -a
mount.nfs: Operation not permitted

I removed the line from /etc/fstab and tried manually:

c ❯ sudo systemctl daemon-reload
c ❯ sudo mount -t nfs 192.168.1.122:/V /srv/nfs/V
mount.nfs: Operation not permitted
c ❯ sudo mkdir -p /mnt/V
c ❯ sudo mount -t nfs 192.168.1.122:/V /mnt/V
mount.nfs: Operation not permitted

linux-aarhus · 24 July 2022 11:00

You need to choose either use fstab or use mount unit. Not both.

Individual-Heart-719 · 24 July 2022 11:05

I know I tried with systemd mount units but it didn’t work, so I deleted the systemd mount units and used fstab instead. I’m going to try following the guide more closely because I always make some modification.

Nachlese · 24 July 2022 11:11

…you can make modifications
once you have established a working variant …

Individual-Heart-719 · 24 July 2022 11:36

I’ve tried again following the instructions more carefully but it’s the same. I remember last time I at least was able to mount the drive but it had the wrong permissions, now it’s not even mounting. Should I reinstall manjaro on both computers and try with a clean install?

s: server, c: client
s ❯ sudo mkdir -p /mnt/V
s ❯ sudo chmod ugo+rwx /mnt/V

Using gnome-disks, Unmount selected partition, select Aditional partition options, select Edit Mount Options..., uncheck User Session Defaults, check Mount at system startup, check Show in user interface, additional options nosuid,nodev,nofail,x-gvfs-show, Mount Point /mnt/V, Identify As /dev/disk/by-uuid/61aea4de-aa02-4f6d-b77d-dc0b09eac2ca, Filesystem Type auto. Click Mount selected partition.

s ❯ ls /mnt/V
works

s ❯ sudo mkdir -p /srv/nfs/V
s ❯ sudo cat /etc/fstab
# /etc/fstab: static file system information.
#
# Use 'blkid' to print the universally unique identifier for a device; this may
# be used with UUID= as a more robust way to name devices that works even if
# disks are added and removed. See fstab(5).
#
# <file system>             <mount point>  <type>  <options>  <dump>  <pass>
UUID=E07B-7D04                            /boot/efi      vfat    umask=0077 0 2
UUID=2155c93c-6df9-458f-a4f7-03bac36ddc44 /              ext4    defaults,noatime 0 1
UUID=1240fd8e-56c9-4e64-a798-2a3cade0cec4 swap           swap    defaults,noatime 0 0
tmpfs                                     /tmp           tmpfs   defaults,noatime,mode=1777 0 0
/dev/disk/by-uuid/61aea4de-aa02-4f6d-b77d-dc0b09eac2ca /mnt/V auto nosuid,nodev,nofail,x-gvfs-show 0 0
/mnt/V /srv/nfs/V none bind 0 0

s ❯ sudo systemctl daemon-reload
s ❯ sudo mount -a
s ❯ sudo cat /etc/exports
# /etc/exports - exports(5) - directories exported to NFS clients
#
# Example for NFSv3:
#  /srv/home        hostname1(rw,sync) hostname2(ro,sync)
# Example for NFSv4:
#  /srv/nfs4        hostname1(rw,sync,fsid=0)
#  /srv/nfs4/home   hostname1(rw,sync,nohide)
# Using Kerberos and integrity checking:
#  /srv/nfs4        *(rw,sync,sec=krb5i,fsid=0)
#  /srv/nfs4/home   *(rw,sync,sec=krb5i,nohide)
#
# Use `exportfs -arv` to reload.
/srv/nfs            192.168.1.0/24(rw,sync,crossmnt,fsid=0)
/srv/nfs/V          192.168.1.0/24(rw,sync)

s ❯ ls -l /srv/nfs
total 4
drwxrwxrwx 5 user user 4096 jul 22 23:23 V

s ❯ ls -l /srv/nfs/V
total 24
drwxrwxrwx  3 user user  4096 jul 22 23:34 dl
drwx------  2 root root 16384 jul 21 18:22 lost+found

s ❯ sudo systemctl enable --now nfs-server.service
c ❯ sudo systemctl enable --now nfs-client.target
c ❯ sudo mkdir -p /mnt/V
c ❯ sudo mount -t 192.168.1.122:/V /mnt/V
mount: /mnt/V: can't find in /etc/fstab.
c ❯ sudo cat /etc/fstab
# /etc/fstab: static file system information.
#
# Use 'blkid' to print the universally unique identifier for a device; this may
# be used with UUID= as a more robust way to name devices that works even if
# disks are added and removed. See fstab(5).
#
# <file system>             <mount point>  <type>  <options>  <dump>  <pass>
UUID=5053-CB3F                            /boot/efi      vfat    umask=0077 0 2
UUID=9b3a496c-b2ab-4bf0-ba72-a1c49e0e82ad /              ext4    defaults,noatime 0 1
UUID=6b1020ba-f8d5-48d9-bd19-3b9c984bd1d8 swap           swap    defaults,noatime 0 0
tmpfs                                     /tmp           tmpfs   defaults,noatime,mode=1777 0 0
arch-desktop01:/nfs/V   /mnt/V  nfs auto,x-systemd.automount,x-systemd.device-timeout=10,timeo=14,x-systemd.idle-timeout=1min 0 0

c ❯ sudo systemctl daemon-reload
c ❯ sudo mount -a
mount.nfs: Failed to resolve server arch-desktop01: Name or service not known

If I replace arch-desktop01 for 192.168.1.122 and repeat the last steps I get:

c ❯ sudo mount -a
Created symlink /run/systemd/system/remote-fs.target.wants/rpc-statd.service → /usr/lib/systemd/system/rpc-statd.service.
mount.nfs: mounting 192.168.1.122:/nfs/V failed, reason given by server: No such file or directory

Nachlese · 24 July 2022 11:49

what was the “working variant”?

I’m too tired right now to assess what you wrote
or to debug it

Individual-Heart-719 · 24 July 2022 11:52

Here I managed to mount the NFS shared folder in the client computer, but all was owned by root and I couldn’t use it. I was using an NTFS partition then, now I’m using an ext4 one.

Is there a way to know if the NFS folder is actually being shared? Can I open with nemo file manager or in some other way other than mounting it?

linux-aarhus · 24 July 2022 13:08

If the service is configured - then likely it is

showmount -e servername

Individual-Heart-719 · 24 July 2022 13:10

It doesn’t seem to be exporting it. I was missing an instruction. That doesn’t appear in the guide.

s ❯ showmount -e arch-desktop01
Export list for arch-desktop01:
s ❯ sudo exportfs -arv
s ❯ showmount -e 192.168.1.122
Export list for 192.168.1.122:
/srv/nfs/V 192.168.1.0/24
/srv/nfs   192.168.1.0/24

linux-aarhus · 24 July 2022 13:23

I am truly impressed.

You are able to completely confuse yourself and run in circles around a truly simple operation.

Ok - I admit - if you are not familiar with *nix concepts it is not simple …

Server

Define device mount using UUID (persistent device name)

device UUID → $(lsbl -no UUID /dev/sdy1)
mount point → /a/nfs

create mount unit a-nfs.mount with content

[Unit]
Description=Demo NFS share mount   
[Mount]
What=/dev/disk/by-uuid/4fdcb623-71ce-4840-ac50-021413cbfd4a
Where=/a/nfs
Options=defaults,rw,noatime   
[Install]
WantedBy=multi-user.target

Mount device
```
systemctl enable --now a-nfs.mount
```
Bind mount in fstab
```
/a/nfs  /srv/nfs/share  none bind 0 0
```
Ensure service folder is created
```
mkdir -p /srv/nfs/share
```
Ensure mount point has rw permissions
```
chmod 777 /a/nfs
```
Ensure NFS service enabled and up
```
systemctl enable --now nfs-server
```

Create NFS export file with a rw share

/srv/nfs        tiger.net.nix.dk(rw,sync,fsid=0,no_subtree_check)
/srv/nfs/share  tiger.net.nix.dk(rw,sync,no_subtree_check)

Reload NFS exports

# exportfs -arv
exporting tiger.net.nix.dk:/srv/nfs/share
exporting tiger.net.nix.dk:/srv/nfs

Verify export

# showmount -e pw0.net.nix.dk
Export list for pw0.net.nix.dk:
/srv/nfs/share tiger.net.nix.dk
/srv/nfs       tiger.net.nix.dk

Client

Verify the share can be reached

$ showmount -e pw0.net.nix.dk
Export list for pw0.net.nix.dk:
/srv/nfs/share tiger.net.nix.dk
/srv/nfs       tiger.net.nix.dk

Define NFS mount and mountpoint

mount point → /a/nfs
mount unit → a-nfs.mount

create mount unit a-nfs.mount with content

[Unit]
Description=Demo NFS share mount

[Mount]
What=pw0.net.nix.dk:/share
Where=/a/nfs
Type=nfs
Options=_netdev,rw

[Install]
WantedBy=multi-user.target

Create automount

automount unit → a-nfs.automount

create automount unit a-nfs.automount with content

[Unit]
Description=Demo NFS client mount

[Automount]
Where=/a/nfs
TimeoutIdleSec=10

[Install]
WantedBy=multi-user.target

Start the mount unit once and stop it

systemctl start a-nfs.mount
systemctl stop a-nfs.mount

Ensure mount point has rw permission
```
chmod 777 /a/nfs
```
Enable and start the automount unit
```
systemctl enable --now a-nfs.automount
```

Done

On the client browse the share using your file manager

fh@tiger ~ $ ls -l /a/nfs
total 0
-rw-r--r-- 1 fh fh 0 Jul 24 16:21 file.txt
fh@tiger ~ $ touch /a/nfs/new_client_file.txt
fh@tiger ~ $ ls -l /a/nfs
total 0
-rw-r--r-- 1 fh fh 0 Jul 24 16:21 file.txt
-rw-r--r-- 1 fh fh 0 Jul 24 17:03 new_client_file.txt

Visualising point made by @winnie in below comment

fh@tiger ~ $ ls /a/nfs
file.txt  new_client_file.txt  non_root_server_user.txt
fh@tiger ~ $ ls -l /a/nfs
total 0
-rw-r--r-- 1 fh   fh   0 Jul 24 16:21 file.txt
-rw-r--r-- 1 fh   fh   0 Jul 24 17:03 new_client_file.txt
-rw-r--r-- 1 1001 1001 0 Jul 24 17:18 non_root_server_user.txt
fh@tiger ~ $ echo "TEST" > /a/nfs/non_root_server_user.txt
bash: /a/nfs/non_root_server_user.txt: cannot overwrite existing file
fh@tiger ~ $ echo "TEST" >> /a/nfs/non_root_server_user.txt
bash: /a/nfs/non_root_server_user.txt: Permission denied
fh@tiger ~ $ ls -l /a/nfs
total 1
-rw-r--r-- 1 fh   fh    0 Jul 24 16:21 file.txt
-rw-r--r-- 1 fh   fh    0 Jul 24 17:03 new_client_file.txt
-rw-r--r-- 1 1001 1001 48 Jul 24 17:22 non_root_server_user.txt
fh@tiger ~ $ cat /a/nfs/non_root_server_user.txt 
fh@pw0.net.nix.dk owns the content of this file
fh@tiger ~ $ cat /a/nfs/file.txt
TEST
fh@tiger ~ $ cat /a/nfs/file.txt
TEST

nix@pw0.net.nix.dk owns this file. 
Because the user have the same UID as fh@tiger both can write the file
Confused?

winnie · 24 July 2022 15:14

The permissions and ownership of the files on the remote NFS server itself must have matching UIDs/GIDs on your local client.

So if on your remote server there exists a UID/GID of 1002/1002, which is the user quake, then on your client computer there must also exist the UID/GID of 1002/1002 (of which the name can be the same if you like.)

This was explained earlier by @megavolt, and I believe it is the main cause of your issues.

If if helps to visualize this differently, imagine NFS as a locally connected drive, yet using an ethernet cable instead of a SATA or USB cable.

Would you expect a locally connected Ext4 drive to “just work” on your computer, if the permissions/ownership of the files on this particular drive don’t even match those of your running system? The same principle applies to NFS (for the most part.)

Individual-Heart-719 · 24 July 2022 15:46

I followed this other guide and it worked. Although I followed the same steps with 4 different drives and I see in all the folders the same files. So it’s like I’ve made 4 mount points in the client computer for the same hard drive from the server. But at least I can use the script in a hard drive from another computer and that’s what I wanted to do, so it’s good enough.

system · 27 July 2022 05:46

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