【ElasticSearch】Kibana 连接不上（Unable to connect to Elasticsearch）

问题：Unable to connect to Elasticsearch

在 Win10 下运行 Kibana.bat，最后出现连接不上 ElasticSearch 的错误：

  log   [15:39:05.169] [info][savedobjects-service] Starting saved objects migrations
  log   [15:39:05.192] [info][savedobjects-service] Creating index .kibana_task_manager_1.
  log   [15:39:05.197] [warning][savedobjects-service] Unable to connect to Elasticsearch. Error: [resource_already_exists_exception] index [.kibana_task_manager_1/wwP1nTsjSH-KydrGNGpdKQ] already exists, with { index_uuid="wwP1nTsjSH-KydrGNGpdKQ" & index=".kibana_task_manager_1" }
  log   [15:39:05.198] [warning][savedobjects-service] Another Kibana instance appears to be migrating the index. Waiting for that migration to complete. If no other Kibana instance is attempting migrations, you can get past this message by deleting index .kibana_task_manager_1 and restarting Kibana.

意思就是，已经存在 .kibana_task_manager_1 索引了，如果没有其他的 Kibana 在使用的话，可以删除它。

解决：删除出错的索引

第一次装，也不懂这些，刚好都有介绍用 elasticsearch-head 来连接 ElasticSearch，所以就去 Github: https://github.com/mobz/elasticsearch-head 上拉取下来，运行起来，访问 http://localhost:9100/ 进去把 .kibana_task_manager_1 删除。

再次运行 Kibana 就可以了。

反思：在网上搜了半天，根本找不到解决办法，原来这么简单，怪自己英语太菜，看都没仔细看就直接到网上搜。问题是，关键词没填对，前面一直警告，就一直在搜警告，服了自己…

  # 最前面的警告
  log   [15:43:15.863] [warning][plugins-discovery] Expect plugin "id" in camelCase, but found: apm_oss
  log   [15:43:15.875] [warning][plugins-discovery] Expect plugin "id" in camelCase, but found: triggers_actions_ui