On the Maintenance page you can perform 3 actions: Reindex Elastic, Update Tenants Configuration or Update Tenant Configuration (Picture 16). Where: 

ElasticSearch is a search engine based on Lucene. It provides a distributed, multitenant-capable full-text search engine with an HTTP web interface and schema-free JSON documents.
It can be used, if there’s information, that isn’t in the Data Base, so in this case,
 Reindex Elastic updates this data and deletes irrelevant data.

To know more about it please follow ElasticSearch Reference documentation: https://www.elastic.co/guide/en/elasticsearch/reference/current/index.html 

Update Tenants Configuration updates all of the tenants in the microservices MS config and Update Tenant Configuration updates current tenant, in which this button will be pressed.


Picture 16. Maintenance options