The configuration for the swh.indexer.journal_client declared in puppet has the following shape:
swh::deploy::indexer_journal_client::config: journal: brokers: "%{alias('swh::deploy::journal::brokers')}" group_id: swh.indexer.journal_client scheduler: "%{alias('swh::remote_service::scheduler::config::writable')}"
Unfortunately, the currently released indexer journal client takes a configuration with a different shape (it takes a top level brokers and group_id).
I think the indexer journal client should be updated for the new config schema, but we can certainly use the old schema in puppet instead.