Re: [PATCH v2 1/1] dlm_controld: support corosync3/knet multi-link

[christine caulfield <ccaulfie@redhat.com>]

On 17/01/2025 15:11, Alexander Aring wrote:
> Hi,
> 
> On Sun, Jan 12, 2025 at 10:13 PM Heming Zhao <heming.zhao@suse.com> wrote:
> ...
>>
>> The current dlm code design doesn't allow reconfiguring the network
>> protocol on the fly. In the above scenario, the dlm will maintain the
>> TCP connection until the next dlm_deamon restart.
>>
>> In my view, it's not essential for dlm to follow the knet dynamically
>> multi-link style. if the user hasn't set the 'protocol' item in
>> dlm.conf, (with my patch, for knet env), dlm will detect the corosync
>> nodelist on startup, and set the appropriate protocol mode.
>>
>> If the user want to keep maintain a multi-link for dlm, they should
>> set protocl item in dlm.conf.
>>
>> On the other hand, if dlm needs to dynamically change the number of
>> links during runtime, it should always use the SCTP protocol.
> 
> to move on here, I would at first apply/ack the patches for the static
> maximum address increase.
> 
> I see no problems to do that as this is required by you.
> 
> For the automatic protocol detection and corosync3, at least I need to
> doing some tests as I have currently 0 ideas how corosync informs the
> users about new/removed links during runtime.
> 

To be honest, it mostly doesn't - and it's maybe something we could look 
into, though I doubt it would be high priority as this is the first time 
it's been thought of :)

Currently you can watch for the cmap key config.reload_in_progress and 
after that goes from 1 back to 0 re-read the new corosync.conf.

Chrissie

> - Alex
>