In this section of the documentation we will explain some general notions of how to migrate between ElasticSearch versions, as well as present specific migration steps to migrate from one version of ElasticSearch used by Apache Unomi to another, if it is needed.
Depending on the type of ElasticSearch install you may have, the migration steps will differ. Basically when dealing with a single node (standalone) installation, a simple procedure may be used that simply copies some directories over, while in the case of a cluster installation ElasticSearch Snapshot and Restore functionality must be used.
In the case of a standalone install, it is generally sufficient, provided the versions are compatible (meaning that only one major version seperates the two installs), to simply copy over the data directory over to the new version. Also you will need to make sure that you copy over any custom settings from the config/elasticsearch.yml file over to the new version.
Here we recommend you read the official upgrading documentation.
Steps: