Fedora xen - Apr 2006 - problems with using xen-get.org images in fc5

Hi,
apart from the FC5 xen install script, I just tried to use the fedory 5 
Image from xen-get.org on a fedora5 host system.

xend is started (the fc5 install script which takes so long runs at the 
same time).
I adjusted the locations of my disk files from the template config that 
came with the cen-get image to match my kernel and disk image file 
locations.

When trying to start the vm, I get the error:
"Error: Error creating domain: Kernel image does not exist: 
/boot/vmlinuz-2.6.16-1.2080_FC5xenU"

But the file is definitely at exactly this location - I just asked a 
colleague for help but he also couldN#t see any error.

I saw that the xen config file generated by the fedora5 install script 
for fc5 domU (/usr/sbin/xenguest-install.py) seems to create a very 
different looking config file than the ones I ever saw in any howto or 
documentation, so I suspect fc5 added some patches to the xen start 
scripts and I must make my config file "somehow" else, but I
don''t see how.
Is it impossible to use a "standard" xen config file in fc5 with the
fc5
provided xen packages?

Henning

Hi,

Henning Sprang wrote:
> [...]
> When trying to start the vm, I get the error:
> "Error: Error creating domain: Kernel image does not exist: 
> /boot/vmlinuz-2.6.16-1.2080_FC5xenU"
I further investigated that.
Fedora seems to require to explicitly set the bootloader to pygrub in 
the domU config.

When doing so, I get the error:

[root@localhost ~]# xm create -c basic-debian
Using config file "/etc/xen/basic-debian".
Traceback (most recent call last):
   File "/usr/bin/pygrub", line 256, in ?
     cf = get_config(file, isconfig)
   File "/usr/bin/pygrub", line 119, in get_config
     fs = fstype.open_fs(fn, offset)
   File "/usr/lib/python2.4/site-packages/grub/fsys/ext2/__init__.py",
line 35, in open_fs
     return Ext2Fs(fn, offset = offset)
ValueError: unable to open file
Error: Boot loader didn''t return any data!


Which seems to be further described here:
http://lists.xensource.com/archives/html/xen-users/2006-03/msg00721.html

But I cannot find a solution. Does that mean I cannot use xen images 
created in block devices the "normal" way all howto''s about
xen describe?

What Do I have to do to create a xen domU manually, or use a xen disk 
image created on another machine/distribution on Fedora?

Why is Fedora not able to recognize the kernel variable in the config 
file correctly as it is usually done on other distributions?


Henning

Ted Kaczmarek wrote:
> 
> Paste your domU config and an ls of /boot, that should help.
"broken" domU config:

#kernel = "/boot/vmlinuz-2.6-xenU"
kernel = "/boot/vmlinuz-2.6.16-1.2080_FC5xenU"
ramdisk= "/boot/initrd-1.6.16-1.2080_FC5xenU.img"
memory = 128
name = "fedora.fc5"
#nics = 1
vif = [ '''' ]
dhcp = "dhcp"
disk = [''file:/var/xen/xen-get-fedora/fedora.fc5.img,sda1,w'', 
''file:/var/xen/xen-get-fedora/fedora.swap,sda2,w'']
root = "/dev/sda1 ro"

#bootloader="/usr/bin/pygrub"


like this, I get:

Using config file "/etc/xen/xen-get-fedora".
Error: Error creating domain: Kernel image does not exist: 
/boot/vmlinuz-2.6.16-1.2080_FC5xenU


[root@localhost ~]# ls -l /boot/
total 12741
-rw-r--r-- 1 root root   63847 Mar 14 22:19 config-2.6.15-1.2054_FC5smp
-rw-r--r-- 1 root root   59663 Mar 28 11:27 config-2.6.16-1.2080_FC5xen0
-rw-r--r-- 1 root root   28213 Mar 28 11:38 config-2.6.16-1.2080_FC5xenU
drwxr-xr-x 2 root root    1024 Apr  8 14:42 grub
-rw-r--r-- 1 root root 1788626 Apr  8 11:40 initrd-2.6.15-1.2054_FC5smp.img
-rw-r--r-- 1 root root 1790016 Apr  8 12:26 initrd-2.6.16-1.2080_FC5xen0.img
-rw-r--r-- 1 root root 1601032 Apr  8 12:26 initrd-2.6.16-1.2080_FC5xenU.img
drwx------ 2 root root   12288 Apr  8 13:35 lost+found
-rw-r--r-- 1 root root  831559 Mar 14 22:19 System.map-2.6.15-1.2054_FC5smp
-rw-r--r-- 1 root root  814854 Mar 28 11:27 System.map-2.6.16-1.2080_FC5xen0
-rw-r--r-- 1 root root  637766 Mar 28 11:38 System.map-2.6.16-1.2080_FC5xenU
-rw-r--r-- 1 root root 1564844 Mar 14 22:19 vmlinuz-2.6.15-1.2054_FC5smp
-rw-r--r-- 1 root root 1529298 Mar 28 11:27 vmlinuz-2.6.16-1.2080_FC5xen0
-rw-r--r-- 1 root root 1232494 Mar 28 11:38 vmlinuz-2.6.16-1.2080_FC5xenU
-rw-r--r-- 1 root root  265927 Mar 28 10:35 xen.gz-2.6.16-1.2080_FC5
-rwxr-xr-x 1 root root  734680 Mar 28 12:04 xen-syms-2.6.16-1.2080_FC5

When I remove the comment before the bootloader line, I get:

Using config file "/etc/xen/xen-get-fedora".
Traceback (most recent call last):
   File "/usr/bin/pygrub", line 256, in ?
     cf = get_config(file, isconfig)
   File "/usr/bin/pygrub", line 119, in get_config
     fs = fstype.open_fs(fn, offset)
   File "/usr/lib/python2.4/site-packages/grub/fsys/ext2/__init__.py",
line 35, in open_fs
     return Ext2Fs(fn, offset = offset)
ValueError: unable to open file
Error: Boot loader didn''t return any data!


The working config generated by the fedora5 script described in the wiki 
looks like:

# Automatically generated xen config file
name = "fedora-simple"
memory = "256"
disk = [ ''file:/var/xen/fedora-simple,xvda,w'' ]
vif = [ ''mac=00:16:3e:16:03:83'' ]
bootloader="/usr/bin/pygrub"

on_reboot   = ''restart''
on_crash    = ''restart''
> 
> 
> I have no problems with any of the images from jailtime.org
> or any of the ones I spun using rpm. These are the same images  that I had
> running on Xen since pre 3.0  from hg checkouts sometime in November of 
> last year.
I''ll see if I can try the same with a jailtime image instead. This can 
take a while because the hardware I had for testing will not be 
available much longer.


Henning

On Apr 9, 2006, at 6:51 AM, Henning Sprang wrote:
> Ted Kaczmarek wrote:
>> Paste your domU config and an ls of /boot, that should help.
>
> "broken" domU config:
>
> #kernel = "/boot/vmlinuz-2.6-xenU"
> kernel = "/boot/vmlinuz-2.6.16-1.2080_FC5xenU"
> ramdisk= "/boot/initrd-1.6.16-1.2080_FC5xenU.img"
> memory = 128
> name = "fedora.fc5"
> #nics = 1
> vif = [ '''' ]
> dhcp = "dhcp"
> disk =
[''file:/var/xen/xen-get-fedora/fedora.fc5.img,sda1,w'',
> ''file:/var/xen/xen-get-fedora/fedora.swap,sda2,w'']
> root = "/dev/sda1 ro"
>
> #bootloader="/usr/bin/pygrub"
>
>
> like this, I get:
>
> Using config file "/etc/xen/xen-get-fedora".
> Error: Error creating domain: Kernel image does not exist: /boot/ 
> vmlinuz-2.6.16-1.2080_FC5xenU
DomU booted right up for me, I pasted my domU config. I am passing  
selinux=0 to kernel on boot,
otherwise I had all kinds of  bad behavior.

# Kernel image file.
kernel = "/boot/vmlinuz-2.6.16-1.2080_FC5xenU"

# Initial memory allocation (in megabytes) for the new domain.
memory = 256

# A name for your domain. All domains must have different names.
name = "idom11"

#----------------------------------------------------------------------- 
-----
# Define the disk devices you want the domain to have access to, and
# what you want them accessible as.
# Each disk entry is of the form phy:UNAME,DEV,MODE
# where UNAME is the device, DEV is the device name the domain will see,
# and MODE is r for read-only, w for read-write.

#disk = [ ''phy:VolGroup01/debian,sdb1,w'' ]
disk = [''file:/media/hdb1/jailtime/fedora.fc5.img,sda1,w'',
''file:/
media/hdb1/jailtime/fedora.swap,sda2,w'']

#----------------------------------------------------------------------- 
-----
# Set the kernel command line for the new domain.
# You only need to define the IP parameters and hostname if the
domain''s
# IP config doesn''t, e.g. in ifcfg-eth0 or via DHCP.
# You can use ''extra'' to set the runlevel and custom
environment
# variables used by custom rc scripts (e.g. VMID=, usr= ).

# Set root device.
root = "/dev/sda1"

# Sets runlevel 4.
#extra = "r0 3 vdso=0"
extra = "ro selinux=0 3"

# Which CPU to start domain on?
#cpu = 1  # leave to Xen to pick

# Number of Virtual CPUS to use, default is 1
vcpus = 2

vif = ['''' ,'''']

# Set if you want dhcp to allocate the IP address.
ip=''off''

on_poweroff = ''destroy''
on_reboot   = ''restart''
#on_crash    = ''restart''
on_crash    = ''destroy''

Regards,
Ted