This functionality is in beta and is subject to change. The design and code is less mature than official GA features and is being provided as-is with no warranties. Beta features are not subject to the support SLA of official GA features.
In time series use cases where you want to follow new indices that are periodically created (such as daily Beats indices), manually configuring follower indices for each new leader index can be an operational burden. The auto-follow functionality in cross-cluster replication is aimed at easing this burden. With the auto-follow functionality, you can specify that new indices in a remote cluster that have a name that matches a pattern are automatically followed.
You can add a new auto-follow pattern configuration with the create auto-follow pattern API. When you create a new auto-follow pattern configuration, you are configuring a collection of patterns against a single remote cluster. Any time a new index with a name that matches one of the patterns in the collection is created in the remote cluster, a follower index is configured in the local cluster. The follower index uses the new index as its leader index.
Since auto-follow functionality is handled automatically in the background on your behalf, error reporting is done through logs on the elected master node and through the cross-cluster replication stats API.