Re: [vserver] fstab.remote and unmounting

From: Daniel Hokka Zakrisson <daniel_at_hozac.com>
Date: Thu 29 Nov 2007 - 19:52:32 GMT
Message-ID: <60075.192.168.102.6.1196365952.squirrel@intranet>

Roderick A. Anderson wrote:
> Daniel Hokka Zakrisson wrote:
>> Roderick A. Anderson wrote:
>>> My thanks to Daniel and Herbert for their help on the IRC (I'm raa)
>>> yesterday. I now have the CIF share mounting in the context/namespace
>>> when the guest is started.
>>>
>>> But when I stop the guest it is not un-mounted and when I start the
>>> guest back up a new mount is created.
>>
>> What makes you think that? When the last process in a namespace exits,
>> everything will be implicitly unmounted.
>
> This is a long post. Sorry but I wanted to show my results.
>
> Some background. Host and guests are CentOS 5 with the latest updates
> off your repository. Four XEON processors. Old system so only single
> cores. Hardware RAID 5.
>
> Here is my testing of various startup processes. Each test is prefixed
> with a ###. As you will see each guest start/restart with a
> fstab.remote CIFS mount shows up as a new mount using df.
>
> As I ran these I got thinking I probably created the guest with strange
> settings so here is the incantation:
>
> vserver $GUEST build -m yum --context $CONTEXT \
> --hostname $FQDN \
> --interface $IFACEID=$NETDEV:$IP/$PREFIX \
> --initstyle sysv -- -d centos5
>
>
> ### Vserver kernel only from a reboot:
>
> [root@admin ~]# df
> Filesystem 1K-blocks Used Available Use% Mounted on
> /dev/rd/c0d0p6 5407568 1775760 3352684 35% /
> /dev/rd/c0d0p1 256666 27898 215516 12% /boot
> tmpfs 1557504 0 1557504 0% /dev/shm
> /dev/rd/c0d0p3 5080828 345592 4472976 8% /var
> /dev/rd/c0d0p2 54668984 4466208 47380960 9% /vservers
> [root@admin ~]# vserver-stat
> CTX PROC VSZ RSS userTIME sysTIME UPTIME NAME
>
> ### Vserver kernel with util-vserver, vprocunhide, and vservers-default
> but no CIFS mount in the rptas guest from a system reboot.
>
> [root@admin ~]# df
> Filesystem 1K-blocks Used Available Use% Mounted on
> /dev/rd/c0d0p6 5407568 1775760 3352684 35% /
> /dev/rd/c0d0p1 256666 27898 215516 12% /boot
> tmpfs 1557504 0 1557504 0% /dev/shm
> /dev/rd/c0d0p3 5080828 345872 4472696 8% /var
> /dev/rd/c0d0p2 54668984 4466320 47380848 9% /vservers
> [root@admin ~]# vserver-stat
> CTX PROC VSZ RSS userTIME sysTIME UPTIME NAME
> 195 7 97.1M 8.5M 0m00s67 0m01s49 0m51s56 db3
> 196 2 4.7M 1.6M 0m00s21 0m00s21 0m43s84 tsdev
> 198 3 9.5M 2.6M 0m00s20 0m00s19 0m44s82 tsda
> 200 3 9.5M 2.7M 0m00s55 0m00s57 0m40s21 rt3
> 204 3 9.5M 2.6M 0m00s60 0m00s61 0m51s56 rptmp
> 1195 3 9.7M 2.5M 0m00s22 0m00s23 0m51s56 asns
> 1196 3 9.8M 2.5M 0m00s23 0m00s20 0m51s56 rptas
> 1197 3 9.8M 2.5M 0m00s22 0m00s21 0m51s56 mx0
> 1199 3 9.8M 2.5M 0m00s23 0m00s22 0m51s56 rad2
>
> ### vserver rptas restart with CIFS mount in the rptas guest:
>
> [root@admin rptas]# df
> Filesystem 1K-blocks Used Available Use% Mounted on
> /dev/rd/c0d0p6 5407568 1775764 3352680 35% /
> /dev/rd/c0d0p1 256666 27898 215516 12% /boot
> tmpfs 1557504 0 1557504 0% /dev/shm
> /dev/rd/c0d0p3 5080828 345892 4472676 8% /var
> /dev/rd/c0d0p2 54668984 4466320 47380848 9% /vservers
> //66.162.136.140/5h4r3@h3l7
> 54668984 4466320 47380848 9%
> /vservers/rptas/mnt/mailas

You're not using fstab.remote here, right? You have an initialize script
doing the mount? Notice how the values are exactly the same as for the
/vservers mount... That's because df is actually probing the /vservers
filesystem. Try cat /proc/mounts to find out what is actually mounted
where. df, mount and friends lie a lot, since they rely solely on
/etc/mtab.

Using fstab.remote will write to the correct mtab file (the one in the
guest). If you want to do the mount from an initialize script, add -n to
your mount command so it doesn't touch /etc/mtab.

> <snip>

-- 
Daniel Hokka Zakrisson
Received on Thu Nov 29 19:52:42 2007
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