elasticsearch red 无法修复，查看发现是unassigned shards 有无法分配的节点的分片
一、问题：集群 red 后，所有节点全部重启恢复不好，查看节点下的数据目录，发现对应索引目录下没有文件
参照博客： http://www.wklken.me/posts/2015/05/23/elasticsearch-issues.html
（还有说法，再加一个节点就会自动分配，我加了节点发现此方法行不通，以下方法操作后，集群状态就 green 了）
通过一系列排查，发现是因为有4个分片未分配到节点上，重启后还无法分配，通过 head 插件可以看到无法分配节点的分片，通过以下命令也可以看到 unassigned shards 有4个无法分配
curl http://192.168.224.188:9200/_cluster/health\?pretty
{
"cluster_name" : "gag-prod",
"status" : "red",
"timed_out" : false,
"number_of_nodes" : 3,
"number_of_data_nodes" : 3,
"active_primary_shards" : 233,
"active_shards" : 466,
"relocating_shards" : 0,
"initializing_shards" : 0,
"unassigned_shards" : 4, \\ 这个就是
"delayed_unassigned_shards" : 0,
"number_of_pending_tasks" : 0,
"number_of_in_flight_fetch" : 0,
"task_max_waiting_in_queue_millis" : 0,
"active_shards_percent_as_number" : 99.14893617021276
}
curl http://192.168.224.188:9200/_cat/shards 从这里找到 UNASSIGNED 类型的索引名字。（和从 head 插件里看到的剩余的分片名字一样）
items22 4 p STARTED 2273 571.1kb 192.168.224.187 gag-prod-node-187
items22 4 r STARTED 2273 571.1kb 192.168.224.188 gag-prod-node-188
items22 2 p UNASSIGNED
items22 2 r UNASSIGNED
items22 1 p STARTED 2284 555.2kb 192.168.224.187 gag-prod-node-187
items22 1 r STARTED 2284 555.2kb 192.168.224.188 gag-prod-node-188
items22 3 p STARTED 2276 641.5kb 192.168.224.187 gag-prod-node-187
items22 3 r STARTED 2276 641.5kb 192.168.224.188 gag-prod-node-188
items22 0 p UNASSIGNED
items22 0 r UNASSIGNED
shop_entity7 4 p STARTED 53 29.6kb 192.168.224.187 gag-prod-node-187
curl http://192.168.224.188:9200_nodes/process?pretty 查看 master节点的唯一标识
{
"cluster_name" : "gag-prod",
"nodes" : {
"tdp1G9DbRseQm8xS9v8jng" : { \\这个是 187 节点的唯一标识
"name" : "gag-prod-node-187",
"transport_address" : "192.168.224.187:9300",
"host" : "192.168.224.187",
"ip" : "192.168.224.187",
"version" : "2.3.2",
"build" : "b9e4a6a",
"http_address" : "192.168.224.187:9200",
"attributes" : {
"master" : "true"
},
"process" : {
"refresh_interval_in_millis" : 1000,
"id" : 10009,
"mlockall" : false
}
},
"a6tktPPYSCOGv4uw8uRclg" : { \\这个是 186 节点的唯一标识
"name" : "gag-prod-node-186",
"transport_address" : "192.168.224.186:9300",
"host" : "192.168.224.186",
"ip" : "192.168.224.186",
"version" : "2.3.2",
"build" : "b9e4a6a",
"http_address" : "192.168.224.186:9200",
"attributes" : {
"master" : "false"
},
"process" : {
"refresh_interval_in_millis" : 1000,
"id" : 24049,
"mlockall" : false
}
},
"d5DvDdr6SLak8YCC099jRg" : { \\这个是 188 节点的唯一标识
"name" : "gag-prod-node-188",
"transport_address" : "192.168.224.188:9300",
"host" : "192.168.224.188",
"ip" : "192.168.224.188",
"version" : "2.3.2",
"build" : "b9e4a6a",
"http_address" : "192.168.224.188:9200",
"attributes" : {
"master" : "true"
},
"process" : {
"refresh_interval_in_millis" : 1000,
"id" : 13058,
"mlockall" : false
}
}
}
}
通过以上操作我们已经找到了 "问题分片"、"节点唯一标识"，现在我们就可以强制把问题分片分配到其中一个节点上了。下面我们将问题分片分到 gag-prod-node-187 上
编辑脚本：（如果有很多unassigned shards，那么可以写循环脚本）
#!/bin/bash
# 将 items22 0 强制分配到 gag-prod-node-187（tdp1G9DbRseQm8xS9v8jng）
curl -XPOST '192.168.224.187:9200/_cluster/reroute' -d '{
"commands" : [ {
"allocate" : {
"index" : "items22",
"shard" : 0,
"node" : "tdp1G9DbRseQm8xS9v8jng",
"allow_primary" : true
}
}
]
}'
# 将 items22 2 强制分配到 gag-prod-node-187（tdp1G9DbRseQm8xS9v8jng）
curl -XPOST '192.168.224.187:9200/_cluster/reroute' -d '{
"commands" : [ {
"allocate" : {
"index" : "items22",
"shard" : 2,
"node" : "tdp1G9DbRseQm8xS9v8jng",
"allow_primary" : true
}
}
]
}'
运行完此脚本后，再查看集群状态，已经恢复，等到此分片自动备份到另一个节点上后，停止 gag-prod-node-187 节点，分片已经可以自动分片节点。
