ERROR: [1] bootstrap checks failed
[1]: the default discovery settings are unsuitable for production use; 
at least one of [discovery.seed_hosts, discovery.seed_providers, cluster.initial_master_nodes] 
must be configured

需要增加启动参数

# 拉取
docker pull elasticsearch:7.6.2

# 单节点启动
docker run -d \
-e ES_JAVA_POTS="-Xms256m -Xmx256m" \
-e "discovery.type=single-node" \
-p 9200:9200 \
-p 9300:9300 \
--name ES1 \
elasticsearch:7.6.2

# 查看所有容器
docker ps -a

# 删除
docker rm <容器ID>

# 查看日志
docker logs -f <容器ID>

参考
Docker 启动 Elasticsearch7.x 报错以及解决方法