No network when PXE booting Live Ubuntu with CIFS

[patpat]

the initrd.lz\initrd\scripts\casper script has a bug

function
do_netmount() {

...
    if [ "${NETBOOT}" != "nfs" ] && do_cifsmount ; then
        rc=0
    elif do_nfsmount ; then
        NETBOOT="nfs"
        export NETBOOT
        rc=0
    fi
...

should be changed to
...
    if [ "${NETBOOT}" != "nfs" ] && do_cifsmount ; then
        export NETBOOT ##<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<
        rc=0
    elif do_nfsmount ; then
        NETBOOT="nfs"
        export NETBOOT
        rc=0
    fi
...

If we use netboot=cifs the variable NETBOOT is not exported and that impacts
initrd.lz\initrd\scripts\casper-bottom\23networking
that ends up recreating with delay and errors /etc/network/interfaces.
Next when Ubuntu boots Internet/Networking is not available.

seen in
 ubuntu-14.04-desktop-amd64.iso
 ubuntu-14.04-desktop-i386.iso

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Кадышев Денис Александрович (metajiji-2)]

Just use CAPS words for cifs:
NETBOOT=cifs

Yes this is magick, but it works!

For nfs use lowercase words:
netboot=cifs

Bug or feature?

[patpat (masottaus)]

just by watching the code it is obvious the export command is missing.

the BUG remains;
I do not see any "feature" here.

[Кадышев Денис Александрович (metajiji-2)]

 Also images affected too:
ubuntu-16.04-desktop-amd64.iso
ubuntu-16.04-desktop-i386.iso

[Guga (tylderon)]

The issues above are easily reproducible at the moment. It's a show-stopper for CIFS netboot deployments. The needed fix is quite simple and a proposed fix can already be found in this thread. Please look into this.

Thanks!

P.S.: Could this bug be edited so that the confirmed newer affected versions are added to it? The devs won't notice it if it only affects casper.

[Guga (tylderon)]

Hello, everyone!

Considering we have a new Ubuntu edition in the oven, could this bug be looked into so its fix can be included in the latest, shiny Ubuntu version as well?

Thanks!

[Guga (tylderon)]

Does anyone know if Zesty is affected as well?

[Bryan Quigley (bryanquigley)]

I've been trying to wrap my head around this feature (and why it's used from the desktop CD) - what is the specific use case? More here: https://community.ubuntu.com/t/anyone-use-cifs-root-in-live-session/1821

This is also relevant because we would need a way to confirm if this bug is fixed or not. Thanks!