Re: [pve-devel] [PATCH qemu-server 1/1] api: migration preconditions: add node affinity as blocking cause

[Fiona Ebner <f.ebner@proxmox.com>]

Am 19.01.26 um 5:54 PM schrieb Daniel Kral:
> On Mon Jan 19, 2026 at 4:00 PM CET, Fiona Ebner wrote:
>> Am 15.12.25 um 4:54 PM schrieb Daniel Kral:
>>> Signed-off-by: Daniel Kral <d.kral@proxmox.com>
>>> ---
>>> Needs a version bump for pve-ha-manager.
>>>
>>
>> Such a bump is only required in the sense that the enum variant cannot
>> actually happen before new ha-manager is installed. The patch here could
>> be applied without such a bump, upgraded and nothing would break.
>>
>> But technically, it's a breaking change in the other direction. New HA
>> manager might cause old qemu-server to return something that was not
>> declared in the return schema. I guess it won't be a huge issue in
>> practice though. API clients already need to be prepared for new
>> variants being returned and the issue would only manifest if the API
>> client checks the correctness of the result against the installed, old
>> qemu-server API schema.
> 
> Well this threw me in an unexpected rabbit hole ;)
> 
> I only added the bump here because I noticed that we do check the
> correctness of the return value of the API handler at the CLI (e.g. if
> `ha-manager migrate vm:100 node1` returns 'node-affinity' as a blocking
> cause), then it will fail
> 
> ```
> # ha-manager migrate vm:100 node1
> 400 Result verification failed
> blocking-resources[0].cause: value 'node-affinity' does not have a value in the enumeration 'resource-affinity'
> ha-manager crm-command migrate <sid> <node>
> ```
> 
> and indeed we verify the result at every CLI invocation [0] (the third
> parameter toggles result verification in [1]).
> 
> One could enable result verification on a case-by-case basis when
> calling the API method directly via the package (e.g.
> PVE::API2::Example->method({ param: "something"}, 1)) [2], but otherwise
> we do not validate the response with pvesh nor the HTTP server [3] [4]
> [5], so this is indeed fine without as bump!

What you are describing here is the breaking change in the other
direction: new ha-manager breaks qemu-server without this patch when
result verification is used.

The bump would technically still not be needed even if we used result
verification everywhere: new qemu-server extends the schema but is
completely fine with old ha-manager, it's just that the new variant
cannot happen then.

> 
> Sorry for going off on a tangent here, I was curious where that
> happened.

That's perfectly fine :)

> 
> [0] https://git.proxmox.com/?p=pve-common.git;a=blob;f=src/PVE/RESTHandler.pm;h=cc82fe8df56a429d64094209d264621de3d4e89e;hb=refs/heads/master#l1019
> [1] https://git.proxmox.com/?p=pve-common.git;a=blob;f=src/PVE/RESTHandler.pm;h=cc82fe8df56a429d64094209d264621de3d4e89e;hb=refs/heads/master#l486
> [2] https://git.proxmox.com/?p=pve-common.git;a=blob;f=src/PVE/RESTHandler.pm;h=cc82fe8df56a429d64094209d264621de3d4e89e;hb=refs/heads/master#l340
> [3] https://git.proxmox.com/?p=pve-common.git;a=blob;f=src/PVE/RESTHandler.pm;h=cc82fe8df56a429d64094209d264621de3d4e89e;hb=refs/heads/master#l232
> [4] https://git.proxmox.com/?p=pve-common.git;a=blob;f=src/PVE/RESTHandler.pm;h=cc82fe8df56a429d64094209d264621de3d4e89e;hb=refs/heads/master#l413
> [5] https://git.proxmox.com/?p=pve-manager.git;a=blob;f=PVE/HTTPServer.pm;h=bb8052e3b428f9b8d11d63f7c7e9d45f40344dca;hb=HEAD#l192
> 
>>
>>>  src/PVE/API2/Qemu.pm | 2 +-
>>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>>
>>> diff --git a/src/PVE/API2/Qemu.pm b/src/PVE/API2/Qemu.pm
>>> index 190878de..5c4f6eb3 100644
>>> --- a/src/PVE/API2/Qemu.pm
>>> +++ b/src/PVE/API2/Qemu.pm
>>> @@ -5196,7 +5196,7 @@ __PACKAGE__->register_method({
>>>                                      type => 'string',
>>>                                      description => "The reason why the HA"
>>>                                          . " resource is blocking the migration.",
>>> -                                    enum => ['resource-affinity'],
>>> +                                    enum => ['node-affinity', 'resource-affinity'],
>>>                                  },
>>>                              },
>>>                          },
> 



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