Thanks Kevin for the response! I believe the fact the `0-0.checkpoint` has been deleted should tell us we > have already written the bootstrap records to the log, either from the > `0-0.checkpoint` or the `bootstrap.checkpoint`, depending on what software > version we formatted with. This is because in order to delete the > `0-0.checkpoint`, there must exist at least one `.checkpoint` file with a > higher offset.
I agree with this, I think it's the correspondence between 'snapshot' and 'checkpoint' which trips me up in some areas of the KIP. E.g. in my first read of the following sentence I read this as "if the 0-0.checkpoint doesn't exist" instead of "if there are no metadata records in the 0-0.checkpoint". > If the controller doesn't load a snapshot at epoch 0 and offset 0, the > controller will load the bootstrap.checkpoint and rewrite the bootstrapping > record to the cluster metadata partition if they haven't been successfully > written in the past. >From reading JR1 it seems maybe it would be helpful to explicitly define what we're referring to when we say 'snapshot' vs 'checkpoint' in the background and make sure the language is consistent throughout the KIP. On Thu, Aug 28, 2025 at 12:03 PM Jun Rao <[email protected]> wrote: > Hi, Jose, > > Thanks for the KIP. > > JR1. "if the snapshot id has an epoch of 0 and a base offset of 0" : I > guess that snapshot here means checkpoint? > > JR2. There seems to be an existing bootstrapping issue related to the > metadata version. KRaft client needs to issue ApiVersionRequest during > initialization. ApiVersionResponse needs to include the finalized metadata > version, which won't be available until KRaft client initializes and > bootstrapping completes. Currently, we just use MINIMUM_VERSION for > metadata in ApiVersionResponse during initialization, which is not > accurate. Should we address this issue here or a separate KIP. > > Jun > > > > On Wed, Aug 27, 2025 at 1:23 PM José Armando García Sancio > <[email protected]> wrote: > > > Hi all, > > > > I would like to start a discussion on KIP-1170: Unify cluster metadata > > bootstrapping: > > > > > https://cwiki.apache.org/confluence/display/KAFKA/KIP-1170%3A+Unify+cluster+metadata+bootstrapping > > > > This KIP unifies the controller's bootstrap checkpoint and KRaft zero > > checkpoint by moving the starting metadata from bootstrap.checkpoint > > to the zero checkpoint. > > > > Thanks, > > > > -- > > -José > > >
