Reindexing from a remote cluster
The snapshot and restore APIs are very fast and the preferred way to back up data, but they have some limitations, such as:
The backup is a safe Lucene index copy, so it depends on the Elasticsearch version used. If you are switching from a version of Elastisearch that is prior to version 5.x, it's not possible to restore old indices.
It's not possible to restore backups of a newer Elasticsearch version in an older version. The restore is only forward-compatible.
It's not possible to restore partial data from a backup.
To be able to copy data in this scenario, the solution is to use the reindex API using a remote server.
Getting ready
You need an up-and-running Elasticsearch installation as we described in the Downloading and installing Elasticsearch recipe in Chapter 2, Downloading and Setup.
To execute curl via command line, you need to install curl for your operative system.
How to do it...
To copy an index from a remote server, we need to execute the following...
