How to set kibana ELASTICSEARCH_URL parameter

I run a elasticsearch and kibana in docker. elasticsearch is run .But kibana can not run . It always try to connected http://elasticsearch:9200 .I set the ELASTICSEARCH_URL kibana command. But not work

I used the command like below.

docker run -d --name d-elasticsearch -p 9200:9200 -p 9300:9300 -e "discovery.type=single-node"

docker run -d --name d-kibana -e ELASTICSEARCH_URL= -p 5601:5601

When I open the http://localhost:5601/. It said Kibana server is not ready yet

Logs like this .
kibana docker log: {"type":"log","@timestamp":"2019-06-05T08:21:26Z","tags":["warning","elasticsearch","data"],"pid":1,"message":"Unable to revive connection: http://elasticsearch:9200/"}

Have you followed the instructions at You must specify elasticsearch.hosts so kibana knows how to connect to elasticsearch

Thank you . I make a mistake. It's ELASTICSEARCH_HOSTS. Not ELASTICSEARCH_URL.
