Content Feeder and CAE Feeder create their indices at the Solr leader when started the first time. To start replication, these indices must be created on Solr followers as well. To create the default indices "studio", "preview" and "live", you have to send the following HTTP requests to the followers. In the example, the Solr follower is running at port 40081:

curl 'http://localhost:40081/solr/admin/cores?action=CREATE&name=studio&configSet=content&dataDir=data'
curl 'http://localhost:40081/solr/admin/cores?action=CREATE&name=preview&configSet=cae&dataDir=data'
curl 'http://localhost:40081/solr/admin/cores?action=CREATE&name=live&configSet=cae&dataDir=data'

The requests specify the name of the created index in the query attribute "name" and the name of the used config set in the attribute "configSet".

Solr followers will start replication after their indices have been created. You can check the state of replication on the Solr follower's admin UI on page Replication after selecting the corresponding Solr core.