Subject: Re: [vserver] Oddity with df
From: Phil Daws <uxbod@splatnix.net>
Date: Wed, 16 May 2012 14:22:10 +0100 (BST)

I added a couple of debug lines into /etc/rc.d/rc.sysinit prior to /etc/mtab being nuked
and rebuilt. Here is the content prior:

/dev/hdv1 / ufs defaults 0 0
none /proc proc defaults 0 0
none /tmp tmpfs size=128m,mode=1777,nosuid,nodev,noexec 0 0
none /dev/pts devpts gid=5,mode=620 0 0

and this is what is in /proc/mounts at that same time:

rootfs / rootfs rw 0 0
/dev/root / ext4 rw,relatime,user_xattr,acl,barrier=1,data=ordered 0 0
none /proc proc rw,nodev,relatime 0 0
none /tmp tmpfs rw,nosuid,nodev,noexec,relatime,size=131072k 0 0
none /dev/pts devpts rw,relatime,gid=5,mode=620 0 0

If /etc/mtab is being rebuilt from /proc/mounts how would one get vserver to populate
it when the guest starts; like it is doing with /etc/mtab ?
-- 
Thanks, Phil

----- Original Message -----
> does anybody else see this with a CentOS 6 guest ?
> --
> Thanks, Phil
> 
> ----- Original Message -----
> > The sysinit script is a core CentOS one not our own. I wonder why
> > hdv1 was not in proc mounts.
> > 
> > Sent from my Android phone using TouchDown (www.nitrodesk.com)
> > 
> > 
> > -----Original Message-----
> > From: Herbert Poetzl [herbert@13thfloor.at]
> > Received: Tuesday, 15 May 2012, 9:28pm
> > To: Phil Daws [uxbod@splatnix.net]
> > CC: vserver@list.linux-vserver.org
> > Subject: Re: [vserver] Oddity with df
> > 
> > 
> > On Tue, May 15, 2012 at 08:53:41PM +0100, Phil Daws wrote:
> > > Well under CentOS6 it looks like /etc/rc.sysinit wipes out
> > > /etc/mtab and re-populates it with data from /proc/mounts. Any
> > > thoughts on the best way to handle this so that:
> > 
> > data from /proc/mounts should be fine with a recent kernel
> > 
> > > /dev/hdv1 / ext2 rw 0 0
> > 
> > > would get pulled in ?
> > 
> > > I have tried creating a guest mtab under
> > > /etc/vservers/<guest>/apps/init and by adding straight into
> > > fstab but no joy :(
> > 
> > as you already stated/concluded, util-vserver populates
> > /etc/mtab correctly, which is then removed by your sysinit
> > script (which is probably useless anyway). at this point
> > util-vserver is not involved in the guest startup anymore.
> > of course, you can start a time delayed script or fix the
> > rc.sysinit to do the right thing ...
> > 
> > best,
> > Herbert
> > 
> > > --
> > > Thanks, Phil
> > 
> > > ----- Original Message -----
> > >> Hmmm, the plot thickens.  Out of curiosity I shut down the guest
> > >> and
> > >> removed the init file /etc/vservers/<guest>/apps/init/style
> > >> which
> > >> contained the text plain.  Now when I start the guest it
> > >> complains
> > >> about upstart issues:
> > 
> > >> initctl: Unable to connect to Upstart: Failed to connect to
> > >> socket
> > >> /com/ubuntu/upstart: Connection refused
> > >> initctl: Unable to connect to Upstart: Failed to connect to
> > >> socket
> > >> /com/ubuntu/upstart: Connection refused
> > 
> > >> but when I check /etc/mtab the hdv is indeed there.  When you
> > >> specify
> > >> plain in the style file how does that alter the boot process as
> > >> it
> > >> appears to be wiping out what is in /etc/mtab ?
> > >> --
> > >> Thanks, Phil
> > 
> > >> ----- Original Message -----
> > >>> Hi Herbert,
> > 
> > >>> Agreed. I shutdown the guest and then ran a simple script which
> > >>> cat
> > >>> /vservers/guest/etc/mtab into another file. I then started the
> > >>> guest
> > >>> and checked the log file for hdv1 and saw:
> > 
> > >>> /dev/hdv1 / ufs defaults 0 0
> > >>> none /proc proc defaults 0 0
> > >>> none /tmp tmpfs size=128m,mode=1777,nosuid,nodev,noexec 0 0
> > >>> none /dev/pts devpts gid=5,mode=620 0 0
> > 
> > >>> then I bit further down it changed too:
> > 
> > >>> none / none rw 0 0
> > 
> > >>> Oh this is going to be a real pain to track down as I do not
> > >>> see
> > >>> anything in /etc/init.d or the upstart configuration files :(
> > >>> --
> > >>> Thanks, Phil
> > 
> > >>> ----- Original Message -----
> > >>>> On Tue, May 15, 2012 at 07:37:34PM +0100, Phil Daws wrote:
> > >>>>> Hi Herbert,
> > 
> > >>>>> When you mentioned about the debug option I did look through
> > >>>>> it
> > >>>>> and checked that file:
> > 
> > >>>>> [root@testvserver01 ~]# cat /lib/util-vserver/defaults/mtab
> > >>>>> /dev/hdv1 / ufs defaults 0 0
> > 
> > >>>>> I also checked the other ones in the findObject call and they
> > >>>>> did not exist. Strange eh ?
> > 
> > >>>> not at all, just means that my original assumption is correct
> > >>>> and something _inside_ your guest removes the file on startup
> > 
> > >>>> HTH,
> > >>>> Herbert
> > 
> > >>>>> --
> > >>>>> Thanks, Phil
> > 
> > >>>>> ----- Original Message -----
> > >>>>>> On Tue, May 15, 2012 at 06:48:47PM +0100, Phil Daws wrote:
> > >>>>>>> Hi Herbert,
> > 
> > >>>>>>> Here is the debug file.
> > 
> > >>>>>> so, what does your /lib/util-vserver/defaults/mtab contain?
> > 
> > >>>>>> best,
> > >>>>>> Herbert
> > 
> > >>>>>>> --
> > >>>>>>> Thanks, Phil
> > 
> > >>>>>>> ----- Original Message -----
> > >>>>>>>> On Tue, May 15, 2012 at 06:03:34PM +0100, Phil Daws wrote:
> > >>>>>>>>> Hi Herbert,
> > 
> > >>>>>>>>> Not that I am aware of. Using the scientific image I
> > >>>>>>>>> built
> > >>>>>>>>> a
> > >>>>>>>>> CentOS6 one and changed the repo URLs. That is all which
> > >>>>>>>>> has
> > >>>>>>>>> been done.
> > 
> > >>>>>>>> well, the guest's mtab is written by util-vserver, so the
> > >>>>>>>> version would be interesting, also mtab can be overridden
> > >>>>>>>> by guest config entries (default and guest specific) which
> > >>>>>>>> might be the case here as well, finally a --debug guest
> > >>>>>>>> start might shed some light on this issue ...
> > 
> > >>>>>>>> best,
> > >>>>>>>> Herbert
> > 
> > >>>>>>>>> --
> > >>>>>>>>> Thanks, Phil
> > 
> > >>>>>>>>> ----- Original Message -----
> > >>>>>>>>>> On Tue, May 15, 2012 at 05:51:13PM +0100, Phil Daws
> > >>>>>>>>>> wrote:
> > >>>>>>>>>>> Hmmm, trawling around it would appear I should see
> > >>>>>>>>>>> something
> > >>>>>>>>>>> like /dev/hdv1 / ext2 rw 0 0 in /etc/mtab. If I check
> > >>>>>>>>>>> and
> > >>>>>>>>>>> older
> > >>>>>>>>>>> vserver system I do see that but not on the latest
> > >>>>>>>>>>> release.
> > >>>>>>>>>>> Has something changed in util-vserver where that does
> > >>>>>>>>>>> not
> > >>>>>>>>>>> automatically get added now ?
> > 
> > >>>>>>>>>> IIRC, newer systems switched to /etc/mtab being a link
> > >>>>>>>>>> to /proc/mounts (which should work fine) so maybe your
> > >>>>>>>>>> setup removes/clears out /etc/mtab inside the guest?
> > 
> > >>>>>>>>>>> --
> > >>>>>>>>>>> Thanks, Phil
> > 
> > >>>>>>>>>>> ----- Original Message -----
> > 
> > >>>>>>>>>>>> Hello,
> > 
> > >>>>>>>>>>>> within our test lab I am trying out 3.2.15-vs2.3.2.8
> > >>>>>>>>>>>> and
> > >>>>>>>>>>>> a
> > >>>>>>>>>>>> few CentOS6 clients. Now that the upstart issues have
> > >>>>>>>>>>>> been
> > >>>>>>>>>>>> resolved all are looking pretty good. One oddity I
> > >>>>>>>>>>>> have
> > >>>>>>>>>>>> noticed is that when I perform a 'df' from within a
> > >>>>>>>>>>>> guest
> > >>>>>>>>>>>> the
> > >>>>>>>>>>>> response is:
> > 
> > >>>>>>>>>>>> df: no file systems processed
> > 
> > >>>>>>>>>>>> is there a new capability flag I am missing ?
> > 
> > >>>>>>>>>> not that I know of ...
> > 
> > >>>>>>>>>> best,
> > >>>>>>>>>> Herbert
> > 
> > >>>>>>>>>>>> --
> > >>>>>>>>>>>> Thanks, Phil
> > 
> > 
> > 
>