[lxc-devel] LXC_DIRECTORY remounted read-only

[Harald Dunkel]

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Hi Serge,

On 08/26/13 13:41, Serge Hallyn wrote:
> 
> Lxc should be creating a $lxcpath/$lxcname/rootfs.hold and keeping that open for write, which should prevent the remount -o ro.  Does that file exist in your case?  Which filesystem is mounted on /export/lxc?
> 

Filesystem is ext4.

It seems that this problem comes up, if I run "halt" within
the container. Using lxc-stop on the server I couldn't
reproduce it by now. Sample session:


{root at cecil:~ 501} lxc-create -t debian -n no2
debootstrap is /usr/sbin/debootstrap
Checking cache download in /var/cache/lxc/debian/rootfs-squeeze-amd64 ...
Copying rootfs to /usr/lib/x86_64-linux-gnu/lxc...Generating locales (this might take a while)...
Generation complete.
update-rc.d: using dependency based boot sequencing
update-rc.d: using dependency based boot sequencing
update-rc.d: using dependency based boot sequencing
update-rc.d: using dependency based boot sequencing
Root password is 'root', please change !

{root at cecil:~ 501} mount | grep /export
/dev/md0p4 on /export type ext4 (rw,noatime,stripe=32,data=ordered)

{root at cecil:~ 501} lxc-start -n no2
INIT: version 2.88 booting
Using makefile-style concurrent boot in runlevel S.
:
:

Debian GNU/Linux 6.0 no2 console

no2 login: root
Password:
Linux no2 3.10.10 #1 SMP PREEMPT Fri Aug 30 06:47:21 CEST 2013 x86_64

root at no2:~# passwd
Enter new UNIX password:
Retype new UNIX password:
passwd: password updated successfully
root at no2:~# halt

Broadcast message from root at no2 (console) (Sat Aug 31 06:19:47 2013):

The system is going down for system halt NOW!
INIT: Switching to runlevel: 0
INIT: Sending processes the TERM signal
Using makefile-style concurrent boot in runlevel 0.
Asking all remaining processes to terminate...done.
All processes ended within 2 seconds....done.
Deconfiguring network interfaces...ifdown: failed to open statefile /etc/network/run/ifstate: Read-only file system
failed.
Cleaning up ifupdown...rm: cannot remove `/etc/network/run/ifstate': Read-only file system
Will now halt.

{root at cecil:~ 501} mount | grep /export
/dev/md0p4 on /export type ext4 (ro,noatime,stripe=32,data=ordered)

{root at cecil:~ 501} ls -al /export/lxc/no2
total 16
drwxr-xr-x  3 root root 4096 Aug 31 08:19 .
drwxr-xr-x  8 root root 4096 Aug 31 08:18 ..
- -rw-r--r--  1 root root 1001 Aug 31 08:18 config
drwxr-xr-x 20 root root 4096 Aug 31 08:19 rootfs
- -rw-------  1 root root    0 Aug 31 08:19 rootfs.hold



AFAICS the file system is remounted read-only, while the container
is still active.

Hope this helps.
Harri

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