ElasticSearch：current license is non-compliant for [security]

注： 部分概念介绍来源于网络

GET /_cluster/health

{
  "error": {
    "root_cause": [
      {
        "type": "security_exception",
        "reason": "current license is non-compliant for [security]",
        "license.expired.feature": "security"
      }
    ],
    "type": "security_exception",
    "reason": "current license is non-compliant for [security]",
    "license.expired.feature": "security"
  },
  "status": 403
}

ES的X-pack许可证是提供免费一个月的试用，但是到期之后，就会报这个错误，需要去es官网注册个账号，然后申请一个新的license，但是注册license 页面上面写着，6.3版本以后，Elastic Stack的默认发行版中包含基本（免费）层功能。无需许可证注册，也就是说，我现在用的6.7.2版本并不需要更新，只需要降级到基础版本即可

POST /_license/start_basic?acknowledge=true
curl -XPOST "http://127.0.0.1:9200/_license/start_basic?acknowledge=true"