Re: [Xen-devel] Inplace upgrading 4.4.x -> 4.5.0

[Steven Haigh <netwiz@xxxxxxxxx>]

On 9/02/2015 8:16 PM, Ian Campbell wrote:
> On Mon, 2015-02-09 at 20:09 +1100, Steven Haigh wrote:
>> On 9/02/2015 7:59 PM, Sander Eikelenboom wrote:
>>> Monday, February 9, 2015, 9:35:33 AM, you wrote:
>>>
>>>> Hello Steven,
>>>> upgrades from Xen 4.4 to 4.5 are supposed to work out of the box.
>>>
>>>> Please post more details and we'll try to help you figure out what's
>>>> wrong.
>>>
>>>> Cheers,
>>>
>>>> Stefano
>>>
>>>> On Sun, 8 Feb 2015, Steven Haigh wrote:
>>>>> Hi all,
>>>>>
>>>>> I was under the impression that you should be able to do in-place
>>>>> upgrades from Xen 4.4 to 4.5 on a system without losing the ability to
>>>>> manage DomUs...
>>>>>
>>>>> This would support upgrades from running systems from Xen 4.4.x to 4.5.0
>>>>> - only requiring a reboot to boot into the 4.5.0 hypervisor.
>>>>>
>>>>> When I try this in practice, I get a whole heap of permission denied
>>>>> errors and lose control of any running DomUs.
>>>>>
>>>>> Is there some secret sauce that will allow this to work?
>>>
>>> You are probably running into a mismatch between the running hypervisor 
>>> (4.4) and 
>>> the now installed toolstack (4.5) .. for instance when trying to shutdown 
>>> the VM's
>>> to do the reboot. 
>>> (Since the newly installed hypervisor parts are only loaded and run on the 
>>> next boot).
>>
>> Correct - It is the 4.4 Hypervisor with 4.5 toolstack. After a reboot,
>> all is good. However this causes the problem - once you update the
>> packages from 4.4 -> 4.5, you lose the ability to manage any running DomUs.
> 
> This sounds like a packaging issue -- Debian's packages for example jump
> through some hoops to make sure multiple tools packages can be installed
> in parallel and the correct ones selected for the currently running
> hypervisor.

Hmmm - that sounds very hacky :\

> Otherwise I think the upgrade path is:
>       * shutdown all VMs (or migrate them away)
>       * install new Xen + tools
>       * reboot
>       * restart domains with new tools.
> 
> I'm afraid that using old tools on a new Xen is not something which is
> supported, even in the midst of an upgrade and AFAIK never has been. The
> N->N+1->N+2 statement is normally with reference to live migration (i.e.
> you can live migrate from a 4.4 system to a 4.5 one).

Hmmm Andrew is correct, the errors are all:

============= xl info ==============
libxl: error: libxl.c:5044:libxl_get_physinfo: getting physinfo:
Permission denied
libxl_physinfo failed.
libxl: error: libxl.c:5534:libxl_get_scheduler: getting domain info
list: Permission denied
host                   : xenhost
release                : 3.14.32-1.el6xen.x86_64
version                : #1 SMP Sun Feb 8 15:41:07 AEDT 2015
machine                : x86_64
xen_major              : 4
xen_minor              : 4
xen_extra              : .1
xen_version            : 4.4.1
xen_caps               : xen-3.0-x86_64 xen-3.0-x86_32p hvm-3.0-x86_32
hvm-3.0-x86_32p hvm-3.0-x86_64
xen_scheduler          : (null)
xen_pagesize           : 4096
platform_params        : virt_start=0xffff800000000000
xen_changeset          :
xen_commandline        : dom0_mem=1024M cpufreq=xen dom0_max_vcpus=1
dom0_vcpus_pin console=tty0 console=com1 com1=115200,8n1
cc_compiler            : gcc (GCC) 4.4.7 20120313 (Red Hat 4.4.7-11)
cc_compile_by          : mockbuild
cc_compile_domain      : crc.id.au
cc_compile_date        : Thu Jan  1 18:19:30 AEDT 2015
xend_config_format     : 4

============= xl list ==============
libxl: error: libxl.c:669:libxl_list_domain: getting domain info list:
Permission denied
libxl_list_domain failed.

============= xl dmesg ==============
libxl: error: libxl.c:6061:libxl_xen_console_read_line: reading console
ring buffer: Permission denied

So, this leads me to wonder - as I'm sure MANY people get bitten by this
- how to control (at least to shutdown) DomUs after an in-place upgrade?

Even if no other functions are implemented other than shutdown, I would
call that an acceptable functionality. At least this way, you're not
hard killing running VMs on reboot.

-- 
Steven Haigh

Email: netwiz@xxxxxxxxx
Web: http://www.crc.id.au
Phone: (03) 9001 6090 - 0412 935 897

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