Zero downtime keeps an Elasticsearch service available while an alias moves client traffic from an old index to a replacement index. Applications continue querying and indexing through the alias instead of addressing a physical index directly. section 6.2.5
Use index aliases to support an uninterrupted index migration:
- Create a replacement index with the required settings and mappings. section 6.2.5
- Point application queries and writes at a stable alias. section 6.2.5
- Designate an is_write_index when one alias targets multiple indexes. section 6.2.5
Switching a cars index
Keep clients using vintage_cars_alias while migration occurs. Remove that alias from vintage_cars, then add it to vintage_cars_new through one _aliases request. Searches and writes continue through the unchanged alias name.
