Configuration of initial cluster state

[muhamadazmy]

Cluster configuration life cycle

• On startup, a ClusterController (Admin) node will seed the metadata with the initial cluster configuration. The seed configuration defaults to a single node cluster but can be overridden via the node config file.
• If configuration already exists in metadata, no initialisation of configuration is needed and metadata becomes source of truth.
• Developer/User can only inspect and/or reconfigure via the restatectl command (or any other grpc client)

What to configure

Cluster configuration should cover all the aspects of cluster setup and replication this includes

• Number of partitions
• Default Bifrost provider. (fixed to replicated ?)
• Replication property
• Node selector strategy
• Scheduler strategy

Developer Experience (DX)

ClusterConfiguration will be managed by MetadataManager. This implies the cluster configuration will be versioned and watchable.

Developers interested in configuration can use the Metadata watcher mechanism to react to changes in configuration. The only prospect right now is the ClusterController (more specifically the LogsController).

Or reconfiguration, LogsController should react by potentially seal and reconfigure the logs.