DEVTMPFS not available in 2.6.32-4-pve kernel

[JohnDoe]

Since I brought up our new server with IPMI-Interface and a serial
console I realized a boot error message just before OS start:

mount: mounting none on /dev failed: No such device                                   
W: devtmpfs not available, falling back to tmpfs for /dev

It seems to me, that the never devtmpfs module is not compiled in.
I couldn't find "CONFIG_DEVTMPFS=y" in /boot/config-2.6.32-4-pve

Is that related to the running debian squeeze? Currently I have only
production systems running debian lenny, so I can't test that issue
on a lenny based system. But I think it is a kernel related issue, so
it's related to the 2.6.32-kernel and not to the underlying OS-version.
Or?

Best regards.

 

[alain]

I cannot say for 2.6.32-4-pve kernel, as I use only 2.6.35 kernel, but with them I have :

# cat config-2.6.35-1-pve |grep CONFIG_DEVTMPFS
CONFIG_DEVTMPFS=y
CONFIG_DEVTMPFS_MOUNT=y

# uname -a
Linux srv-kvm3 2.6.35-1-pve #1 SMP Thu Dec 16 06:05:58 CET 2010 x86_64 GNU/Linux

So it seems to be there in this kernel.

Alain

 

[JohnDoe]

$ cat /boot/config-2.6.32-4-pve | grep CONFIG_DEVTMPFS
$ cat /boot/config-2.6.32-4-pve | grep DEVTMPFS

as I said before nothing is found on 2.6.32-pve kernel.

@PROXMOX team: could you please fix this in the next 2.6.32-pve kernel release?


Best regards.

 

[dietmar]

@PROXMOX team: could you please fix this in the next 2.6.32-pve kernel release?
[/QUOTE]

I thing the warning you get is from grub2, but it is totally harmless.

2.6.32 has no support for DEVTMPFS. (conflicts with CONFIG_VE)

 

[holgerb]

I thing the warning you get is from grub2, but it is totally harmless.
2.6.32 has no support for DEVTMPFS. (conflicts with CONFIG_VE)

Are there chances that a future Proxmox kernel will integrate DEVTMPFS as well ?
Or does this feature always colide with CONFIG_VE ?

The reason why I am asking is the dependecy of certain OpenVZ templates on DEVTMPFS.
Since the main target distribution for our server products is OpenSuse / SLES I grabbed an OpenVZ template for OpenSuse 11.3 AMD64 (and OpenSuse 11.4 as well) from here:
http://wiki.openvz.org/Download/template/precreated

Both templates "bomb out" when creating a VZ container because devtempfs is not available.

There is a small snippet inside the VZ template under /etc/init.d/boot which checks if devtempfs is avaible:

DTYPE=$(stat -f -c "%T" /dev 2>/dev/null)
if test "$DTYPE" != "tmpfs" ; then
    if test "$HAVE_DEVTMPFS" = "0" ; then
       echo "************************* FATAL ERROR *************************"
       echo "******* CONFIG_DEVTMPFS missing from kernel, cannot continue..."
       echo "***************************************************************"
       /sbin/halt -f
    fi
    echo -n "Mounting devtmpfs at /dev"
    mount -n -t devtmpfs -o mode=0755 devtmpfs /dev
    rc_status -v -r
fi

As "workaround" I have disabled this check completely and mounted /dev via tempfs. There are several warnings when accessing /dev/console from rc_status but beside this the VZ container is starting up at least.

DTYPE=$(stat -f -c "%T" /dev 2>/dev/null)
if test "$DTYPE" != "tmpfs" ; then
    #if test "$HAVE_DEVTMPFS" = "0" ; then
    #   echo "************************* FATAL ERROR *************************"
    #   echo "******* CONFIG_DEVTMPFS missing from kernel, cannot continue..."
    #   echo "***************************************************************"
    #   /sbin/halt -f
    #fi
    echo -n "Mounting tmpfs at /dev"
    mount -n -t tmpfs -o mode=0755 tmpfs /dev
    rc_status -v -r
fi

I will check if our server stuff is running but in the end it would be nice to get rid of all this error messages

 

[dietmar]

Are there chances that a future Proxmox kernel will integrate DEVTMPFS as well ?
Or does this feature always colide with CONFIG_VE ?

That is a question for the OpenVZ team - please can you ask on the OpenVZ list instead? So far there is no OpenVZ kernel with DEVTMPFS enabled.

 

[holgerb]

That is a question for the OpenVZ team - please can you ask on the OpenVZ list instead? So far there is no OpenVZ kernel with DEVTMPFS enabled.

Ok, I posted in the OpenVZ support forum. If noone replies I will forward the question to the OpenVZ mailing list. It is really "funny" that someone provided an OpenVZ template which doesn't work in the first place.

I would care less if there would be an OpenVZ template for OpenSuse with the usage of devtmpfs. Personally I do not feel like digging through all Suse startup scripts to eliminate all devtmpfs dependecies.