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

[Masaki Kanno <kanno.masaki@xxxxxxxxxxxxxx>]

Hi,

Next, I tested xen-unstable 15967 without staging 15973.
I think that new problems occur by staging 15973.  I will investigate 
causes to solve new problems.

[xm create]
 if an UUID is specified:
     if a VM with same name exists:
         if the VM is same UUID too:
             ==> xm create failed
             Error: VM name 'vm1' already exists as domain 1
             
         else:
             ==> xm create failed
             Error: VM name 'vm1' already exists as domain 1
             
     else:
         if a VM with same UUID exists:
             ==> xm create succeed... Right?
             
         else:
             ==> xm create succeed
             
 else:
     if a VM with same name exists:
         ==> xm create failed
         Error: VM name 'vm1' already exists as domain 1
         
     else:
         ==> xm create succeed
         

[xm new]
 if an UUID is specified:
     if a VM with same name exists:
         if the VM is same UUID too:
             ==> xm new failed
             Error: VM name 'vm1' already exists as domain 1
             
         else:
             ==> xm new failed
             Error: Domain name 'vm1' is already used.
             
     else:
         if a VM with same UUID exists:
             ==> xm new failed
             Error: Domain UUID '191a8164-aaff-c9fe-63b4-493eba17021a' 
                    is already used.
         else:
             ==> xm new succeed
             
 else:
     if a VM with same name exists:
         ==> xm new failed
         Error: VM name 'vm1' already exists as domain 1
         
     else:
         ==> xm new succeed
         

Best regards,
 Kan

Fri, 28 Sep 2007 12:59:27 +0900, Masaki Kanno wrote:

>Hi,
>
>I tested xen-unstable 15967 and staging 15973.
>
>[xm create]
> if an UUID is specified:
>     if a VM with same name exists:
>         if the VM is same UUID too:
>             ==> xm create succeed, but...
>             # xm list
>             Name     ID   Mem VCPUs      State   Time(s)
>             Domain-0  0   491     2     r-----    109.3
>             vm1       2   256     1     r-----   3636.3
>             vm1       4   256     1     --p---      0.0
>             
>         else:
>             ==> xm create failed
>             Error: VM name 'vm1' already exists as domain 2
>             
>     else:
>         if a VM with same UUID exists:
>             ==> xm create succeed... Right?
>             
>         else:
>             ==> xm create succeed
>             
> else:
>     if a VM with same name exists:
>         ==> xm create failed
>         Error: VM name 'vm1' already exists as domain 2
>         
>     else:
>         ==> xm create succeed
>         
>
>[xm new]
> if an UUID is specified:
>     if a VM with same name exists:
>         if the VM is same UUID too:
>             ==> xm new failed?  but an error message was not shown.
>             # xm new /xen/vm2.conf name="vm1"
>             Using config file "/xen/vm2.conf".
>             # xm list
>             Name     ID   Mem VCPUs      State   Time(s)
>             Domain-0  0   491     2     r-----    243.9
>             vm1       2   256     1     r-----  10003.1
>             
>         else:
>             ==> xm new failed
>             Error: Domain name 'vm1' is already used.
>             
>     else:
>         if a VM with same UUID exists:
>             ==> xm new failed
>             Error: Domain UUID '3ef95bbe-57a9-1caf-9a15-27ab27eb66b3' 
>                    is already used.
>         else:
>             ==> xm new succeed
>             
> else:
>     if a VM with same name exists:
>         ==> xm new failed?  but an error message was not shown.
>         
>     else:
>         ==> xm new succeed
>         
>
>Best regards,
> Kan
>
>Thu, 27 Sep 2007 17:50:51 +0100, "Daniel P. Berrange" wrote:
>
>>Changeset  15124:f5459c358575 altered check_name() in XendDomainInfo so that
>>it compares domain IDs instead of UUIDs. This breaks a number of things
>>
>> - You can no longer use 'xm new' to define a persistent config file for
>>   a running guest. This breaks the key OS provisioning scenario where
>>   you boot a kenrel+initrd for the installer, and at the same time define
>>   a permanent config with pygrub.
>>
>> - It lets you define multiple inactive guests with different UUIDs, but  
>>   the same name because all inactive guests have a domid of None. So you
>>   can now end up with multiple guests with same name, which is contrary
>>   to the goal implied by the patch which was name uniqueness.
>>
>>It is unclear from the original commit logs just what scenario it was trying
>>to protect against, but the original checking of uniqueness based on UUID 
>>was correct & is what was used in previous releases XenD.
>>
>>Thus the attached patch reverts 15124
>>
>>   Signed-off-by: Daniel P. Berrange <berrange@xxxxxxxxxx>
>>
>>Regards,
>>Dan.
>>-- 
>>|=- Red Hat, Engineering, Emerging Technologies, Boston.  +1 978 392 2496 
>>|-=|
>>|=-           Perl modules: http://search.cpan.org/~danberr/              
>>|-=|
>>|=-               Projects: http://freshmeat.net/~danielpb/               
>>|-=|
>>|=-  GnuPG: 7D3B9505   F3C9 553F A1DA 4AC2 5648 23C1 B3DF F742 7D3B 9505  -
>>|=| 
>>


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