Bug#476535: [Debian] Re: Bug#476535: vzctl: Possibility to mount/bind into VE fs

[Peter Gervai]

Hello Everyone,

On Thu, Apr 24, 2008 at 1:01 PM, Ola Lundqvist <opal at debian.org> wrote:

>  Hi Christian
>
>  Thanks for the clarification. I have marked this bugreport as wontfix
>  because of the vzmigrate issue, and because that this already exists
>  even though it is not document.
>
>  However maybe it should be documented, but that is a separate issue. :)

First, this must be documented, in 'man vzctl' (probably at files
section, but I'd mention it in start/stop/mount/umount sections as
well), and there ought to be example files provided (the ones
Christian quoted are just fine; except exit values should be mentioned
/ demonstrated, like checking existence of the mounted-into directory
and fail accordingly).

Second, should I try to open a bug for it in Debian BTS and edit the
manpage and provide a patch, or (preferably) any of you would love to
get it done? :-)

Third, vzmigrate manpage should mention this problem about in-mounted
subtrees, and maybe check it even before progressing, but I cannot
tell out of my brain whether there is a portable check for that.
Still, I believe more people would mount large storage into VE than
use vzmigrate. ;-)

Thanks for your time & efforts,
Peter

ps: still gotta test whether .mount and .umount works ;) not that I
don't trust you, erm... I mean... :-))

>
>  Best regards,
>
>  // Ola
>
>  On Thu, Apr 24, 2008 at 10:23:33AM +0200, Christian Hofstaedtler wrote:
>  > Hi!
>  >
>  > > > >  Do we need a poststop as well?
>  > > >
>  > > > You're right, I happen to be lazy and usually let the system to umount
>  > > > all; but with high probability we should umount every manually mounted
>  > > > cruft before stop tries to unmount the whole VE, so a prestop should
>  > > > exist the same way prestart was implemented.
>  >
>  > > > And by all means feel free to post it upstream, you may be more
>  > > > familiar with the process than I am now.
>  >
>  > We are doing similar things with the /etc/vz/conf/$VEID.mount and
>  > /etc/vz/conf/$VEID.umount scripts; they are automatically handled by
>  > vzctl, but I'm not sure this is documented (except somewhere buried
>  > in old VZ pdfs).
>  >
>  > mount and umount obviously run at vzctl mount/umount time, which is
>  > pretty much pre-start and post-stop, and also does the "right thing"
>  > if manually starting/stopping a VE.
>  > These scripts can also prevent a VE from starting/stopping, if they
>  > return a non-zero value.
>  >
>  > Maybe you want to look at these first?
>  >
>  > Examples:
>  > cat /etc/vz/conf/201004.mount
>  > #!/bin/sh
>  > mount -onoatime /dev/raid10/ve201004-pg /var/lib/vz/root/201004/srv/db/pg
>  >
>  > cat /etc/vz/conf/201004.umount
>  > #!/bin/sh
>  > umount /dev/raid10/ve201004-pg
>  > exit 0 # ignore error from umount
>  >
>  >
>  > BTW, mounting filesystems into VEID/root probably breaks vzmigrate,
>  > so one needs to be careful :-)
>  >
>  > -Christian
>  >
>  >
>  >
>  >
>
>  --
>   --------------------- Ola Lundqvist ---------------------------
>  /  opal at debian.org                     Annebergsslingan 37      \
>  |  ola at inguza.com                      654 65 KARLSTAD          |
>  |  http://inguza.com/                  +46 (0)70-332 1551       |
>  \  gpg/f.p.: 7090 A92B 18FE 7994 0C36  4FE4 18A1 B1CF 0FE5 3DD9 /
>   ---------------------------------------------------------------
>
>



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