Arch Linux

dropdeadgreggie

Member

Registered: 2013-10-29

Posts: 11

[Solved]NBD fails to boot when copyonwrite = true.

I setup a diskless client following the arch wiki article using NBD. I setup up the install exactly how I wanted it and then I enabled copyonwrite in /etc/nbd-server/config, restarted the service, and now it fails to boot. I would like to use the same image for multiple clients.

When I boot I get:

: : running hook [nbd]
nbd_host = 10.14.14.1
nbd_name = kiosk
nbd_port =
loading module. . .
connecting. . .
Negotiation: . .Error: Server closed connection
Exiting.
: : mounting '/dev/nbd0" on real root
mount: wrong fs type, bad option, bad superblock on /dev/nbd0,
            missing codepage or helper program, or other error

            In some cases useful info is found in syslog -try
            dmesg | tail or so.
You are now being dropped into an emergency shell.
sh: can't access tty; job control off
[rootfs /]#

My /etc/nbd-server/config is as follows:

                                                                            
[generic]
        user = nbd
        group = nbd
[kiosk]
        exportname = /srv/nbd/kiosk/arch.img
        copyonwrite = true

Thank you in advance for your help!

Last edited by dropdeadgreggie (2013-11-04 19:11:23)

dropdeadgreggie

Member

Registered: 2013-10-29

Posts: 11

Re: [Solved]NBD fails to boot when copyonwrite = true.

Another problem I've run into is that the NBD service doesn't run as root, therefore I have to change the permissions on "arch.img" so that the filesystem can be mounted read write.

dropdeadgreggie

Member

Registered: 2013-10-29

Posts: 11

Re: [Solved]NBD fails to boot when copyonwrite = true.

journalctl -n shows:

nbd_server[6436]: Could not create diff file (Permission denied)

Fixed it:

chown nbd /srv/nbd/kiosk

Last edited by dropdeadgreggie (2013-11-04 19:10:54)