Re: [Xen-users] Re: creating a xen failover with lookback images

[Heiko <rupertt@xxxxxxxxx>]

On Mon, Jul 28, 2008 at 1:33 PM, Heiko <rupertt@xxxxxxxxx> wrote:
> On Mon, Jul 28, 2008 at 1:18 PM, Heiko <rupertt@xxxxxxxxx> wrote:
>> On Thu, Jul 24, 2008 at 7:19 PM, Daniel Asplund <danielsaori@xxxxxxxxx> 
>> wrote:
>>>>> Hello,
>>>>> i want to setup a VM which has another VM as failover.
>>>>> We use images where we store the VM in.
>>>>> Most people use drbd and heartbeat for this, is this the best solution
>>>>> fors this?
>>>>>
>>>>> When I use XEN images, how do I have to define the image in drbd?
>>>>>
>>>>>  on ares.bluethings.net {
>>>>>    device     /dev/drbd0;
>>>>>    disk       /dev/sda5;
>>>>>    address    172.16.6.2:7788;
>>>>>    flexible-meta-disk  internal;
>>>>>  }
>>>>>
>>>> Am I right that the guy in this
>>>> http://marksitblog.blogspot.com/2007/07/mysql-5-high-availability-with-drbd-8.html
>>>> guide is using drbd inside the VM to mirror the /dev/sda1 inside the VM?
>>>>
>> Hi Daniel,
>> i reinstalled both servers and now have LVM.
>> Since I dont use the Xen-tools and use CentOS, i would like to install
>> the VM with virt-install,
>> I started the installation with:
>>
>> virt-install \
>> --name=ticketsystem \
>> --ram=2000 \
>> --file=/dev/vg01/lv_myVM \
>
> --file=/dev/vg01/lv_myVM \  should be --file=/dev/drdb0 i guess
>
>> --vcpus=2 \
>> --os-variant=centos5 \
>> --nographics \
>> --location ftp://wftp.tu-chemnitz.de/pub/linux/centos/5.2/os/x86_64/ \
>>
>> it ran thorugh, now I did shut it down and changed the VM config:
>>
>> disk = [ "drdb:ticketsystem,xvda1,w" , 
>> "file:/VM/ticketsystem_swap.img,xvda2,w"]
>>
still wont boot:

 xm create  ticketsystem -c
Using config file "./ticketsystem".
Traceback (most recent call last):
  File "/usr/bin/pygrub", line 651, in ?
    fs = fsimage.open(file, get_fs_offset(file))
IOError: [Errno 95] Operation not supported
No handlers could be found for logger "xend"
Error: Boot loader didn't return any data!

I did a complete reinstall to /dev/drbd0

> should be  disk = [ "drbd:ticketsystem,xvda1,w" ,
> "file:/VM/ticketsystem_swap.img,xvda2,w"]
>
>
>
>> [root@pc] xm create ticketsystem -c
>> Using config file "/etc/xen/ticketsystem".
>> No handlers could be found for logger "xend"
>> Error: Disk isn't accessible
>>
>> It looks like xend doesnt like the drbd thing?
>>
>> how can i get this working?
>>
>> thx
>>
>>>> thx
>>>>
>>>
>>> Yeah, he is running DRBD inside the VM to allow for failover with
>>> heartbeat of the VMs.
>>>
>>> I believe using LVM, DRBD and heartbeat is the best solution for this,
>>> it will give you a very flexible solution. I run this myself. Not
>>> inside the VMs but on the Dom0 nodes. But the principle is the same
>>> when configuring it. Cool solution would be to run a cluster both on
>>> the Dom0s and inside the DomUs, maybe something to try. :)
>>>
>>
>>
>>> Please have a look at my XEN cluster guide at:
>>> http://www.asplund.nu/xencluster/xen-cluster-howto.html
>>> It is not fully complete but maybe you can get some ideas about the DRBD 
>>> setup.
>>>
>>> Cheers, Daniel
>>>
>>> _______________________________________________
>>> Xen-users mailing list
>>> Xen-users@xxxxxxxxxxxxxxxxxxx
>>> http://lists.xensource.com/xen-users
>>>
>>
>

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