[Lxc-users] lxc-execute: Input/output error - failed to read

[Mike Ivanov]

Hi there,

This is what happens on a freshly installed Ubuntu 10.10 Maverick 
Meerkat (2.6.35):

# lxc-version
lxc version: 0.7.2

# mkdir /lxc
# /usr/lib/lxc/templates/lxc-ubuntu -p /lxc
.....
I: Retrieving tar
I: Validating tar
I: Retrieving tzdata
I: Validating tzdata
I: Retrieving udev
.....
Please change root-password !

# ls
config  fstab  rootfs

# cat config
lxc.utsname = xxx

lxc.tty = 4
lxc.pts = 1024
lxc.rootfs = /lxc/rootfs
lxc.mount  = /lxc/fstab

lxc.cgroup.devices.deny = a
# /dev/null and zero
lxc.cgroup.devices.allow = c 1:3 rwm
lxc.cgroup.devices.allow = c 1:5 rwm
# consoles
lxc.cgroup.devices.allow = c 5:1 rwm
lxc.cgroup.devices.allow = c 5:0 rwm
lxc.cgroup.devices.allow = c 4:0 rwm
lxc.cgroup.devices.allow = c 4:1 rwm
# /dev/{,u}random
lxc.cgroup.devices.allow = c 1:9 rwm
lxc.cgroup.devices.allow = c 1:8 rwm
lxc.cgroup.devices.allow = c 136:* rwm
lxc.cgroup.devices.allow = c 5:2 rwm
# rtc
lxc.cgroup.devices.allow = c 254:0 rwm

# cat fstab
proc            /lxc/rootfs/proc         proc    nodev,noexec,nosuid 0 0
devpts          /lxc/rootfs/dev/pts      devpts defaults 0 0
sysfs           /lxc/rootfs/sys          sysfs defaults  0 0


All was perfect so far.
Now, this is the place where things become less beautiful:

# lxc-execute -n xxx -f config /bin/bash
root at xxx:/# lxc-execute: Input/output error - failed to read
root at xxx:/# root at xxx:/# exit

[2]+  Stopped                 lxc-execute -n xxx -f config /bin/bash

# fg
lxc-execute -n xxx -f config /bin/bash
#

Note it somehow manages to send itself to background.

lxc-start simply hangs. When /sbin/init is started with --verbose it 
says somewhere in the middle:

init: mountall main process (3) executable changed
init: hostname main process (4) terminated with status 1
init: hostname goal changed from start to stop


Now, what's interesting, if I comment out the lxc.rootfs line in config, 
it gives me perfectly functional bash:

# lxc-execute -n xxx -f config /bin/bash
root at xxx:/lxc# pwd
/lxc
root at xxx:/lxc# ps ax
   PID TTY      STAT   TIME COMMAND
     1 ?        S      0:00 /usr/lib/lxc/lxc-init -- /bin/bash
     2 ?        S      0:00 /bin/bash
    12 ?        R+     0:00 ps ax
root at xxx:/lxc#


Even more interesting: if I add a line like "lxc.rootfs = /" to the 
config file ("/" is the default value, right?) it breaks again:

# lxc-execute -n xxx -f config /bin/bash
root at xxx:/# lxc-execute: Input/output error - failed to read


So my question is what I'm doing wrong? If that's not me, is it 
something fixed in 0.7.3?

Thanks,
Mike