cat shards

shards 命令详细的描述了节点包含的分片信息。它将告诉您它是一个主分片还是一个副本,和文档的数量,硬盘上占用的字节数,以及节点所在的位置。下面我将看一个单独的索引,它有 3 个主分片和 0 个副本。

% curl 192.168.56.20:9200/_cat/shards
wiki1 0 p STARTED 3014 31.1mb 192.168.56.10 H5dfFeA
wiki1 1 p STARTED 3013 29.6mb 192.168.56.30 bGG90GE
wiki1 2 p STARTED 3973 38.1mb 192.168.56.20 I8hydUG

Index pattern(索引模式)

如果有许多分片,您也许想要限制在输出中显示的索引。您可以一直使用 grep,但是您可以通过提供一个 index pattern(索引模式)到尾部以节省带宽。

% curl 192.168.56.20:9200/_cat/shards/wiki*
wiki2 0 p STARTED 197 3.2mb 192.168.56.10 H5dfFeA
wiki2 1 p STARTED 205 5.9mb 192.168.56.30 bGG90GE
wiki2 2 p STARTED 275 7.8mb 192.168.56.20 I8hydUG

Relocation(迁移)

假设您在检测集群健康时发现迁移的分片。它们原来在哪里,并且迁移到哪呢?

% curl 192.168.56.10:9200/_cat/health
1384315316 20:01:56 foo green 3 3 12 6 2 0 0
% curl 192.168.56.10:9200/_cat/shards | fgrep RELO
wiki1 0 r RELOCATING 3014 31.1mb 192.168.56.20 I8hydUG -> 192.168.56.30 bGG90GE
wiki1 1 r RELOCATING 3013 29.6mb 192.168.56.10 H5dfFeA -> 192.168.56.30 bGG90GE

Shard states(分片状态)

在一个分配能使用之前,它会经过一个 **INITIALIZING**(初始化)状态,**shards** 可以告诉您更详细的信息。

% curl -XPUT 192.168.56.20:9200/_settings -d'{"number_of_replicas":1}'
{"acknowledged":true}
% curl 192.168.56.20:9200/_cat/shards
wiki1 0 p STARTED      3014 31.1mb 192.168.56.10 H5dfFeA
wiki1 0 r INITIALIZING    0 14.3mb 192.168.56.30 bGG90GE
wiki1 1 p STARTED      3013 29.6mb 192.168.56.30 bGG90GE
wiki1 1 r INITIALIZING    0 13.1mb 192.168.56.20 I8hydUG
wiki1 2 r INITIALIZING    0   14mb 192.168.56.10 H5dfFeA
wiki1 2 p STARTED      3973 38.1mb 192.168.56.20 I8hydUG

如果一个分片不能够被分配,例如,你分配的分片数量超过了集群中节点的数量,分片将保持 **UNASSIGNED**(未分配的)状态与 [reason code](https://www.elastic.co/guide/en/elasticsearch/reference/5.0/cat-shards.html#reason-unassigned "Reasons for unassigned shardedit")(异常代码)ALLOCATION_FAILED(分配失败)。``

% curl -XPUT 192.168.56.20:9200/_settings -d'{"number_of_replicas":3}'
% curl 192.168.56.20:9200/_cat/health
1384316325 20:18:45 foo yellow 3 3 9 3 0 0 3
% curl 192.168.56.20:9200/_cat/shards
wiki1 0 p STARTED    3014 31.1mb 192.168.56.10 H5dfFeA
wiki1 0 r STARTED    3014 31.1mb 192.168.56.30 bGG90GE
wiki1 0 r STARTED    3014 31.1mb 192.168.56.20 I8hydUG
wiki1 0 r UNASSIGNED ALLOCATION_FAILED
wiki1 1 r STARTED    3013 29.6mb 192.168.56.10 H5dfFeA
wiki1 1 p STARTED    3013 29.6mb 192.168.56.30 bGG90GE
wiki1 1 r STARTED    3013 29.6mb 192.168.56.20 I8hydUG
wiki1 1 r UNASSIGNED ALLOCATION_FAILED
wiki1 2 r STARTED    3973 38.1mb 192.168.56.10 H5dfFeA
wiki1 2 r STARTED    3973 38.1mb 192.168.56.30 bGG90GE
wiki1 2 p STARTED    3973 38.1mb 192.168.56.20 I8hydUG
wiki1 2 r UNASSIGNED ALLOCATION_FAILED

Reasons for unassigned shard

对于在 unassigned state(未分配状态)中的分片,这里有一些可能的原因 : 

| Reason Code(异常代码) | Description(描述) | | INDEX_CREATED | Unassigned as a result of an API creation of an index. | | CLUSTER_RECOVERED | Unassigned as a result of a full cluster recovery. | | INDEX_REOPENED | Unassigned as a result of opening a closed index. | | DANGLING_INDEX_IMPORTED | Unassigned as a result of importing a dangling index. | | NEW_INDEX_RESTORED | Unassigned as a result of restoring into a new index. | | EXISTING_INDEX_RESTORED | Unassigned as a result of restoring into a closed index. | | REPLICA_ADDED | Unassigned as a result of explicit addition of a replica. | | ALLOCATION_FAILED | Unassigned as a result of a failed allocation of the shard. | | NODE_LEFT | Unassigned as a result of the node hosting it leaving the cluster. | | REROUTE_CANCELLED | Unassigned as a result of explicit cancel reroute command. | | REINITIALIZED | When a shard moves from started back to initializing, for example, with shadow replicas. | | REALLOCATED_REPLICA | A better replica location is identified and causes the existing replica allocation to be cancelled. |