Clients not booting on NFS root image

[Xpons]

Hi, we are working long time ago with LTSP5, and now we are trying to move to the 'new' LTSP. With LTSP5 we use a read only NFS ubuntu image and clients mount with a tmpfs overlay upper layer this lower layer filesystem.

With LTSP v20.03 we get an error on 55-initrd-bottom.sh script execution of 'read-only filesystem' and client startup fail (see attached image). Script on install_ltsp function tries to sync and remove on NFS read only filesystem without mount any overlay fs.
Please, what we are doing wrong?

On this script I found this comment:

Make root writable using a tmpfs overlay and install ltsp-init

@LTSP.CONF: IMAGE OVERLAY

exists some variable 'IMAGE OVERLAY' on LTSP.conf?, I have not found any documentation about this. And seems like in older versions( 19.12-1) script 55-initrd-bottom.sh and 55-init.sh was responsible to mount the overlay layer but now only exists this comentary header but nothing more.

It's a code bug or a misconfiguration we have?
thank you very much

Xpons

[alkisg]

Hi, can you upload your /srv/tftp/ltsp/ltsp.ipxe, and the output of ltsp info?

[Xpons]

Hi,
yes here are the ltsp info output:

root@LTSP2020:/srv/tftp/ltsp# ltsp info
LTSP version: 20.03.1-1202003221407ubuntu18.04.1

SERVER OS: PRETTY_NAME="Ubuntu 18.04.4 LTS"

CHROOTS:
UDS20200306
UDSlocal

VMs:

IMAGES:
x86_64

and attached our ltsp.ipxe:

ltsp_ipxe.txt

The two images UDS20200306 and UDSlocal are the NFS root images

Thank you
Xpons

[alkisg]

Does it boot from x86_64?

[Xpons]

Yes, X86_64 it's a squashfs image and works without problem, only both NFS images (UDS20200306 and UDSlocal) fail boot because not rw overlay over readonly NFS filesystem it's created.

[alkisg]

@Xpons, thanks, you're right, the fix for #43 broke chroot-over-NFS booting. Are you able to apply and test the following patch? You'll need to run sudo ltsp initrd after applying it on the server.

diff --git a/ltsp/client/initrd-bottom/55-initrd-bottom.sh b/ltsp/client/initrd-bottom/55-initrd-bottom.sh
index b31a2a5..6d60b60 100644
--- a/ltsp/client/initrd-bottom/55-initrd-bottom.sh
+++ b/ltsp/client/initrd-bottom/55-initrd-bottom.sh
@@ -40,11 +40,14 @@ initrd_bottom_main() {
             re umount "$rootmnt"
             img_src="$tmpfs/${img##*/}$rest"
         fi
-        re mount_img_src "$img_src" "$rootmnt" "$tmpfs"
-        re set_readahead "$rootmnt"
-    elif [ ! -d "$rootmnt/proc" ]; then
+    elif [ -d "$rootmnt/proc" ]; then
+        # Plain NFS chroot booting
+        img_src=$rootmnt
+    else
         die "$rootmnt/proc doesn't exist and ltsp.image wasn't specified"
     fi
+    re mount_img_src "$img_src" "$rootmnt" "$tmpfs"
+    re set_readahead "$rootmnt"
     test -d "$rootmnt/proc" || die "$rootmnt/proc doesn't exist in $_APPLET"
     re install_ltsp
 }

P.S. I edited the patch, please test with the updated version.

[alkisg]

Thanks, fix committed in cc407ed, please reopen if it's still an issue.

I'll upload a new 20.04 version in the PPA.