new shards are allocated on the next creation of the index.
Say you have an index filebeat-2019.09.24 and change whatever settings on its template. The next index creation, which would be 2019.09.25 is when the new index would grab the new settings and create it.
you can 1) wait until the next index creation date or, 2) reindex, which is to reindex, say, index A to index B, delete index A.
If you write to an alias, it should work fine, but if you must write to the original name of index A (for example, filebeat-2019.09.24) do the following:
reindex filebeat-2019.09.24 to filebeat-temp (will take some time depeding on disk speed, size of index, etc)
Apache, Apache Lucene, Apache Hadoop, Hadoop, HDFS and the yellow elephant
logo are trademarks of the
Apache Software Foundation
in the United States and/or other countries.