How to reindex without Reindex API

Elastic Stack Elasticsearch
1

To reduce the number of shards, I changed the configuration file. Now my elasticsearch creates a new index like [indexname]-2018.06.

Next, I need to reindex the existing indices to consolidate into monthly indices. It looks very easy to do if you have a newer elasticsearch. IndexAPI or Curator. But my system is 1.6.0. How can I do?

2

May be you can use logstash with an elasticsearch input and elasticsearch output.

Or build a script that calls scroll API then bulk API.

But you really need to upgrade to 6.x!