[druid-user] [ANNOUNCE] Apache Druid 0.21.0 release

The Apache Druid team is proud to announce the release of Apache Druid 0.21.0.
Druid is a high performance analytics data store for event-driven data.

Apache Druid 0.21.0 contains around 120 new features, bug fixes,
performance enhancements, documentation improvements, and additional
test coverage from 36 contributors. Major new features and
improvements include:

- Service discovery and leader election based on Kubernetes (experimental)
- New 'grouping' aggregator function
- Native parallel ingestion no longer requires explicit intervals
- Native re-ingestion is less memory intensive
- Improved web console styles
- New Coordinator duty and query metrics

Source and binary distributions can be downloaded from:
https://druid.apache.org/downloads.html

Release notes are at:

A big thank you to all the contributors in this milestone release!