继上篇处理分片分配失败的故障处理，去官网整理了ES分片的所有UNASSIGNED的原因，留以备用。

INDEX_CREATED

Unassigned as a result of an API creation of an index.
索引创建 由于API创建索引而未分配的

CLUSTER_RECOVERED

Unassigned as a result of a full cluster recovery.
集群恢复 由于整个集群恢复而未分配

INDEX_REOPENED

Unassigned as a result of opening a closed index.
索引重新打开

DANGLING_INDEX_IMPORTED

Unassigned as a result of importing a dangling index.
导入危险的索引

NEW_INDEX_RESTORED

Unassigned as a result of restoring into a new index.
重新恢复一个新索引

EXISTING_INDEX_RESTORED

Unassigned as a result of restoring into a closed index.
重新恢复一个已关闭的索引

REPLICA_ADDED

Unassigned as a result of explicit addition of a replica.
添加副本

ALLOCATION_FAILED

Unassigned as a result of a failed allocation of the shard.
分配分片失败

NODE_LEFT

Unassigned as a result of the node hosting it leaving the cluster.
集群中节点丢失

REROUTE_CANCELLED

Unassigned as a result of explicit cancel reroute command.
reroute命令取消

REINITIALIZED

When a shard moves from started back to initializing, for example, with shadow replicas.
重新初始化

REALLOCATED_REPLICA

A better replica location is identified and causes the existing replica allocation to be cancelled.
重新分配副本