- https://www.elastic.co/blog/found-elasticsearch-from-the-bottom-up
- https://www.elastic.co/blog/found-sizing-elasticsearch
- shard: https://aws.amazon.com/blogs/database/get-started-with-amazon-elasticsearch-service-how-many-shards-do-i-need/
- https://www.codementor.io/ashish1dev/getting-started-with-elasticsearch-du107nett
docker run -p 9200:9200 -p 9300:9300 -e "discovery.type=single-node" docker.elastic.co/elasticsearch/elasticsearch:6.2.4