Re: [pve-devel] [RFC] qemu-server: add migration_type=insecure to remote-migrate

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

Am 30.04.26 um 2:38 PM schrieb Fabian Grünbichler:
> On April 25, 2026 3:10 am, Bogdan Ionescu wrote:
>>
>> == Backward compatibility approach ==
>>
>> Rather than bumping WS_TUNNEL_VERSION (which would break
>> new-source -> old-target combinations because of the existing
>> "$WS_TUNNEL_VERSION > $tunnel->{version}" check), I'd add a
>> forward-compatible 'caps' field to the version response. Old sources
>> ignore unknown JSON keys; new sources require 'insecure-remote' to be
>> present in caps before allowing migration_type=insecure, and otherwise
>> fall through to the existing WS-tunneled path with no behavioral
>> change.
> 
> what do you think @Fiona?

Sorry for the very late response. I think a two-way negotiation is
better for the long term. Because with the proposed approach, i.e.
"target informs source, source decides what to do", the target cannot
directly know whether the source will (be able to) use a certain
capability or not and thus the target is not be able to adapt its
commandline/handling depending on the capabilities alone.

I think there should rather be a dedicated 'capabilities' handler rather
than the capabilities being part of the 'version' handler and then:
1. The source sends along the capabilities it wants to use.
2. The target looks at the capabilities and decides which ones it also
supports/wants and returns the result to the source. This will be a
strict subset of the ones the source sent along.
3. Both source and target know which capabilities are going to be used
and can proceed accordingly.

Best Regards,
Fiona