elasticsearch无法访问9200端口

        近期部署elasticsearch后，启动时发现一直报如下错误:

curl: (7) Failed connect to localhost:9200； Connection refused

部署的版本为elasticsearch-7.13.2,排查原因是因为开启了ssl认证。

解决方法:

在/opt/software/elasticsearch-7.13.2/config下修改elasticsearch.yml配置,添加如下内容:

xpack.security.http.ssl.enabled: false

日志报错2如下:

org.elasticsearch.bootstrap.StartupException: java.lang.IllegalStateException: failed to obtain node locks, tried [[/data/es/data]] with lock id [0]; maybe these locations are not writable or multiple nodes were started without increasing [node.max_local_storage_nodes] (was [1])?

解决方法:
        修改配置文件elasticsearch.yml，并最后添加如下内容:vim ./config/elasticsearch.yml

node.max_local_storage_nodes: 2