Hi Kuan-Po,

> L03
> In KAFKA-19563, you mentioned introducing a new
--add-controller-command-config option to separate admin and
controller configs. That sounds like a solid approach.

Yes, that can resolve the issue in KAFKA-19563, but it conflicts with the
motivation in the KIP:
   1. Limited Accessibility: The node executing the tool must have direct
access to the metadata path of the node being added or removed. This
restricts the ability to use node A to manage node B, as node A may not
have access to the metadata folder on node B.
   2. Dependency on Node Configuration: The tool requires access to the
configuration of the node being managed.

> That said, I was thinking of an alternative:
 what if we change the logic so that *when both* --command-config
*and* --controller-id are provided, the command config only applies
to admin initialization? Users can add extra admin properties in
--command-config.

I'm good with it.

>L04
> As jose mentioned, the controller (observer) endpoints are stored in the
ClusterImage

Yes, I like this idea since we already have endpoint information stored in
the active controller.

Thank you.
Luke


On Fri, Aug 1, 2025 at 12:40 AM Chia-Ping Tsai <chia7...@gmail.com> wrote:

> hi Kuan-Po
>
> Yeah, I agree — to make things easier, we could enhance the logic.
> If the user provides --bootstrap-server, we can retrieve
> controller.quorum.bootstrap.servers from the broker configs
> using admin.describeConfigs, and use that to get the required
> controller configs.
>
>
> As jose mentioned, the controller (observer) endpoints are stored in the
> ClusterImage.
>
> Another (more complicated) approach would be to make the endpoints in
> AddRaftVoterRequest optional.
>
> Initially, I thought this KIP could address this issue in a simple way,
> without requiring any changes to the RPC :)
>
> Best,
> Chia-Ping
>
> Kuan-Po Tseng <brandb...@gmail.com> 於 2025年8月1日 週五 上午12:05寫道:
>
> > Hi Luke,
> >
> > Appreciate the feedback — glad to finally see some voices in this thread!
> > :)
> >
> > *L01, L02:*
> > Sure thing!
> >
> > *L03:*
> > Thanks for the heads-up — I hadn’t thought of that before.
> > In KAFKA-19563, you mentioned introducing a new
> > --add-controller-command-config option to separate admin and
> > controller configs. That sounds like a solid approach.
> >
> > That said, I was thinking of an alternative:
> > what if we change the logic so that *when both* --command-config
> > *and* --controller-id are provided, the command config only applies
> > to admin initialization? Users can add extra admin properties in
> > --command-config.
> >
> > What do you think?
> >
> > *L04:*
> > Yeah, I agree — to make things easier, we could enhance the logic.
> > If the user provides --bootstrap-server, we can retrieve
> > controller.quorum.bootstrap.servers from the broker configs
> > using admin.describeConfigs, and use that to get the required
> > controller configs.
> >
> > Then we could allow users to run something like:
> >
> > bin/kafka-metadata-quorum.sh --bootstrap-server localhost:9092 \
> >   add-controller --controller-id <id>
> >
> >
> > Best,
> > Kuan-Po
> >
> > On Thu, Jul 31, 2025 at 3:24 PM Luke Chen <show...@gmail.com> wrote:
> >
> > > Hi Kuan-Po,
> > >
> > > Thanks for the KIP!
> > > We also faced the similar issue recently.
> > >
> > > Some suggestions/questions:
> > > 1. Could you also include the issue in  KAFKA-19563
> > > <https://issues.apache.org/jira/browse/KAFKA-19563> as the motivation
> in
> > > the KIP?
> > > 2. Could you make it clear in the KIP that after the KIP, the
> > > add-controller request from kafka-metadata-quorum.sh will take more
> time
> > > than before because of more API calls needed?
> > > 3. "If —-command-config is provided, fallback to the existing behavior,
> > and
> > > —-controller-id option will be ignored."
> > > On this, it looks like it still doesn't resolve the issue described in
> > > KAFKA-19563 <https://issues.apache.org/jira/browse/KAFKA-19563>
> because
> > if
> > > the client wants to pass the "client.id", and provide a properties
> file
> > in
> > > --command-config, it 'll be treated as the controller.properties and
> fail
> > > the request, right? Ex:
> > > `bin/kafka-metadata-quorum.sh --bootstrap-controller localhost:9093
> > > add-controller --controller-id <id> --command-config admin.properties`
> > > 4. "This can only be done with bootstrap controller option since we
> can‘t
> > > use bootstrap.server in Admin#describeConfigs to get controller
> configs."
> > > I understand the reason but it makes the script more confusing in my
> > > opinion.
> > > I'm wondering why we need the controller endpoint when talking with the
> > > broker with --bootstrap-server? The controller endpoint should already
> > > exist in broker itself, right?
> > >
> > > Thank you.
> > > Luke
> > >
> > > On Sat, Apr 19, 2025 at 11:32 PM Kuan Po Tseng <brandb...@apache.org>
> > > wrote:
> > >
> > > > Hi José,
> > > >
> > > > Apologies for the delayed response. Do you still have any questions
> > > > regarding the describeConfig part? As Chia-Ping mentioned, we are
> able
> > to
> > > > retrieve all broker configurations through that method. (
> > > >
> > >
> >
> https://github.com/apache/kafka/blob/da46cf6e79afbbed1da2bae831e0f70992e85f9b/core/src/main/scala/kafka/server/ConfigHelper.scala#L121-L123
> > > > )
> > > >
> > > > Please feel free to reach out if you have any further questions or
> need
> > > > clarification. Thank you again for your valuable feedback!
> > > >
> > > > Best,
> > > > Kuan-Po Tseng
> > > >
> > > > On 2025/04/03 16:04:36 José Armando García Sancio wrote:
> > > > > Hi Chia,
> > > > >
> > > > > On Thu, Apr 3, 2025 at 10:24 AM Chia-Ping Tsai <
> chia7...@apache.org>
> > > > wrote:
> > > > > > We propose to use `Admin#describeConfigs` to get the configs for
> > > > specific controller if the bootstrap.controllers is configured. This
> > > > approach is similar to what `MetadataQuorumCommand` does, and the
> > > > difference is `MetadataQuorumCommand` read those configs from local
> > file
> > > > and this KIP gets those configs by `Admin#describeConfigs`
> > > > >
> > > > > I am not sure. I have to look at that code but doesn't
> > > > > "Admin#describeConfigs" only return dynamic configuration for the
> > > > > controller? Most users configure the controller using the server
> > > > > properties file. My current understanding is that values coming
> from
> > > > > the properties file won't show up in Admin#describeConfigs.
> > > > >
> > > > > Thanks,
> > > > > --
> > > > > -José
> > > > >
> > > >
> > >
> >
>

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