how to deploy elasticsearch7 cluster on kubernetes1.19

1. apply statefulset.yaml

   curl -LO https://chenshi.net/es-sts.yaml
   vi es-sts.yaml
   kubectl apply -f es-sts.yaml
   

2. references:

   https://rancher.com/blog/2018/2018-11-22-deploying-elasticsearch/

   https://stackoverflow.com/questions/61540373/elasticsearch-7-x-setup-on-kubernetes