Re: [Xen-devel] PATCH: Fix name uniqueness check

[Masaki Kanno <kanno.masaki@xxxxxxxxxxxxxx>]

Fri, 5 Oct 2007 14:35:16 +0100, "Daniel P. Berrange" wrote:

>On Fri, Oct 05, 2007 at 02:19:16PM +0900, Masaki Kanno wrote:
>> Tue, 2 Oct 2007 15:47:12 +0100, "Daniel P. Berrange" wrote:
>> 
>> >On Tue, Oct 02, 2007 at 10:11:01PM +0900, Masaki Kanno wrote:
>> >> Hi Dan,
>> >> 
>> >> Thanks for your effort and your patch. 
>> >> I think that the allow/reject rules are wonderful.  But, I have a few 
>> >> comments. 
>> >> 
>> >> 
>> >> I agree the rule of the following case. 
>> >> But, the behavior is (redefine+rename+create), isn't it?
>> >
>> >Yes, that is actually what it ends up doing, replacing the config for the 
>> >matching UUID causes a rename.
>> >
>> >> When I tested the following case, the result was as follows. 
>> >> I think that we should reject xm new command if same UUID vm is active. 
>> >
>> >I hadn't noticed that, but its easy to special case this particular
>> >case / scenario to be rejected. Or we could fix it to correctly rename
>> >the existing running VM which might be more user friendly. 
>> >
>> >Either option is a small add-on patch to my previous submissions.
>> 
>> Sorry for delay with replies to your message. 
>> 
>> I am worried about changing the configuration of existing running VM. 
>> But, my worry is vague, and does not have great grounds. 
>> If UUID is same, maybe we will become possible to change the name of 
>> the VM and all the configuration of the VM by xm new command, I guess. 
>> 
>> If only the config.sxp of the VM is changed by xm new command, and if 
>> the definition of the config.sxp is reflected after xm shutdown command, 
>> my worry will be resolved. 
>
>Kan, give this patch a try which simply updates the name_label field for
>the exsting VM. With this minimal rename it avoids the risk of the same VM
>being started twice as you demonstrated 
>

Hi Dan,

Thank you.  The problem that I found first was resolved. 

# xm create /xen/vm1.conf uuid="11111111-2222-3333-4444-555555555555"
Using config file "/xen/vm1.conf".
Started domain vm1
# xm list
Name                                        ID   Mem VCPUs      State   Time(s)
Domain-0                                     0   747     2     r-----    389.8
vm1                                          2   256     1     -b----      1.3
# xm new /xen/vm2.conf uuid="11111111-2222-3333-4444-555555555555"
Using config file "/xen/vm2.conf".
# xm list
Name                                        ID   Mem VCPUs      State   Time(s)
Domain-0                                     0   747     2     r-----    392.5
vm2                                          2   256     1     ------     18.2


But, I found another problem...  When I rebooted the VM, the name of the VM 
was restored to 'vm1'.  Could you fix the problem too? 

# xm new /xen/vm1.conf uuid="11111111-2222-3333-4444-555555555555"
Using config file "/xen/vm1.conf".
# xm start vm1
# xm list
Name                                        ID   Mem VCPUs      State   Time(s)
Domain-0                                     0   747     2     r-----    410.3
vm1                                          3   256     1     -b----     26.2
# xm new /xen/vm2.conf uuid="11111111-2222-3333-4444-555555555555"
Using config file "/xen/vm2.conf".
# xm reboot vm2
# xm list 
Name                                        ID   Mem VCPUs      State   Time(s)
Domain-0                                     0   747     2     r-----    420.4
vm1                                          4   256     1     -b----     25.8


Best regards,
 Kan



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