ElasticSearch重启之后shard未分配导致个别索引为“红色”状态

1. Check the cluster allocation explain API

GET /_cluster/allocation/explain

2.根据错误提示执行相应命令

POST /_cluster/reroute?retry_failed=true

3.查看原先“红色”状态的索引分片情况

GET /_cat/shards?index=index_name

参考：Health check on my ES cluster shows 99.7%
记一次ElasticSearch重启之后shard未分配问题的解决