ElasticSearch 解决 429: es_rejected_execution_exception

ElasticSearch日志中出现如下内容:

[INFO ] 2020-06-04 11:04:45.093 [[main]>worker16] elasticsearch - retrying failed action with response code: 429 ({"type"=>"es_rejected_execution_exception", "reason"=>"rejected execution of processing of [74000580][indices:data/write/bulk[s][p]]: request: BulkShardRequest [[mail-w3svc1-2020.05.31][0]] containing [10] requests, target allocation id: 6OPCe3kOTWqG5k68lRozUA, primary term: 1 on EsThreadPoolExecutor[name = it_elk_node171/write, queue capacity = 200, [email protected]aa695f[Running, pool size = 40, active threads = 40, queued tasks = 200, completed tasks = 31488344]]"})

原因分析:

为了防止集群过载,Elasticsearch在设计之初就限制了请求队列的大小, 从而增加了稳定性和可靠性。如果没有限制,客户端可以很容易地通过不良或恶意行为将整个群集关闭。所以在并发查询量大的情况下,访问流量超过了集群中单个Elasticsearch实例的处理能力,Elasticsearch服务端会触发保护性的机制,拒绝执行新的访问,并且抛出EsRejectedExecutionException异常。

这个保护机制与异常触发是由Elasticsearch API实现中的thread pool与配套的queue决定的. 在上面的错误日志中,Elasticsearch为index操作分配的线程池,pool size=40, queue capacity=200,当40个线程处理不过来,并且队列中缓冲的tasks超过200个,那么新的task就会被简单的丢弃掉,并且抛出EsRejectedExecutionException异常。

Elasticsearch将此条日志的级别定义为INFO, 说明它不是一个严重的问题, 根据ElasticSearch官方文档, 有时候甚至不用太关心, 但是依旧可以做一些有效的事来改善它.

定位与解决

根据ElasticSearch官方文档, 要解决429错误, 只有如下途径:

1, 暂停bulk write过程3-5秒钟,  然后重试.

2, 增加thread pool的write线程池相关参数.

thread pool的write线程池相关参数, 可以通过如下命令来获得:

curl -XGET "127.0.0.1:9200/_cat/thread_pool/write?v&h=node_name,ip,name,active,queue,rejected,completed,core,type,pool_size,queue_size"
node_name      ip           name  active queue rejected completed core type  pool_size queue_size
it_elk_node169 172.29.4.169 write      0     0     1174  22801844      fixed        40        200
it_elk_node168 172.29.4.168 write      0     0     1811  32356307      fixed        40        200
it_elk_node167 172.29.4.167 write     30     0    11797  39593375      fixed        40        200
it_elk_node171 172.29.4.171 write      0     0    12304  28194291      fixed        40        200
it_elk_node170 172.29.4.170 write      1     0      743  25107047      fixed        40        200

其中, active和queue表示当前消耗的线程数与队列数, pool_size和queue_size表示系统设置的线程数和队列数.

从ElasticSearch 5开始, 无法再通过cluster API去调整thread pool的设置(官网说明):

Thread pool settings are now node-level settings. As such, it is not possible to update thread pool settings via the cluster settings API.

解决办法

size表示线程数, 不能超过CPU核数.

vim elasticsearch.yml    # 添加如下内容
thread_pool:
    write:
        size: 30
        queue_size: 1000

然后重启ES. 重启之后, 再看, 就会发现pool_size和queue_size的值发生了变化

curl -X GET "127.0.0.1:9200/_cat/thread_pool/write?v&h=node_name,ip,name,active,queue,rejected,completed,core,type,pool_size,queue_size"
node_name      ip           name  active queue rejected completed core type  pool_size queue_size
it_elk_node167 172.29.4.167 write      0     0        0   1305481      fixed        40       3000
it_elk_node169 172.29.4.169 write      0     0        0   4266653      fixed        40        200
it_elk_node168 172.29.4.168 write      0     0     7280   7097169      fixed        40        200
it_elk_node170 172.29.4.170 write      0     0        0   2271912      fixed        40       3000
it_elk_node171 172.29.4.171 write      0     0        0   4377790      fixed        40       3000

同样的, 也可以通过类似的命令, 查看get/ccr(跨集群复制)/search的pool_size/queue_size

# 查看所有node详细的thread_pool
curl -X GET "127.0.0.1:9200/_nodes/thread_pool?pretty=true"


# 查看search的pool_size/queue_size
curl -X GET "127.0.0.1:9200/_cat/thread_pool/search?v&h=node_name,ip,name,active,queue,rejected,completed,core,type,pool_size,queue_size"
node_name      ip           name   active queue rejected completed core type                  pool_size queue_size
it_elk_node167 172.29.4.167 search      0     0        0      8418      fixed_auto_queue_size        61       1000
it_elk_node169 172.29.4.169 search      0     0        0     64923      fixed_auto_queue_size        61       1000
it_elk_node168 172.29.4.168 search      0     0        0    111409      fixed_auto_queue_size        61       1000
it_elk_node170 172.29.4.170 search      0     0        0     50890      fixed_auto_queue_size        61       1000
it_elk_node171 172.29.4.171 search      0     0        0     38820      fixed_auto_queue_size        61       1000

# 查看get的pool_size/queue_size
curl -X GET "127.0.0.1:9200/_cat/thread_pool/get?v&h=node_name,ip,name,active,queue,rejected,completed,core,type,pool_size,queue_size"
node_name      ip           name active queue rejected completed core type  pool_size queue_size
it_elk_node167 172.29.4.167 get       0     0        0       819      fixed        40       1000
it_elk_node169 172.29.4.169 get       0     0        0       331      fixed        40       1000
it_elk_node168 172.29.4.168 get       0     0        0      4756      fixed        40       1000
it_elk_node170 172.29.4.170 get       0     0        0         9      fixed         9       1000
it_elk_node171 172.29.4.171 get       0     0        0      6193      fixed        40       1000


# 查看ccr(跨集群复制)的pool_size/queue_size
curl -X GET "127.0.0.1:9200/_cat/thread_pool/ccr?v&h=node_name,ip,name,active,queue,rejected,completed,core,type,pool_size,queue_size"
node_name      ip           name active queue rejected completed core type  pool_size queue_size
it_elk_node167 172.29.4.167 get       0     0        0       819      fixed        40       1000
it_elk_node169 172.29.4.169 get       0     0        0       331      fixed        40       1000
it_elk_node168 172.29.4.168 get       0     0        0      4756      fixed        40       1000
it_elk_node170 172.29.4.170 get       0     0        0         9      fixed         9       1000
it_elk_node171 172.29.4.171 get       0     0        0      6193      fixed        40       1000


# 查看所有thread pool
curl -XGET "127.0.0.1:9200/_cat/thread_pool?v&h=id,ip,name,queue,rejected,completed"
id                     ip           name                queue rejected completed
VbBadlehSNqlXKtWGlyUvA 172.29.4.156 analyze                 0        0         0
VbBadlehSNqlXKtWGlyUvA 172.29.4.156 ccr                     0        0    140182
VbBadlehSNqlXKtWGlyUvA 172.29.4.156 fetch_shard_started     0        0         0
VbBadlehSNqlXKtWGlyUvA 172.29.4.156 fetch_shard_store       0        0        60
VbBadlehSNqlXKtWGlyUvA 172.29.4.156 flush                   0        0      8700
VbBadlehSNqlXKtWGlyUvA 172.29.4.156 force_merge             0        0         0
VbBadlehSNqlXKtWGlyUvA 172.29.4.156 generic                 0        0   1267594
VbBadlehSNqlXKtWGlyUvA 172.29.4.156 get                     0        0    158496
VbBadlehSNqlXKtWGlyUvA 172.29.4.156 listener                0        0     16736
VbBadlehSNqlXKtWGlyUvA 172.29.4.156 management              0        0   7373132
VbBadlehSNqlXKtWGlyUvA 172.29.4.156 refresh                 0        0  15758014
VbBadlehSNqlXKtWGlyUvA 172.29.4.156 rollup_indexing         0        0         0
VbBadlehSNqlXKtWGlyUvA 172.29.4.156 search                  0        0   1474802
VbBadlehSNqlXKtWGlyUvA 172.29.4.156 search_throttled        0        0         0
VbBadlehSNqlXKtWGlyUvA 172.29.4.156 security-token-key      0        0         0
VbBadlehSNqlXKtWGlyUvA 172.29.4.156 snapshot                0        0         2
VbBadlehSNqlXKtWGlyUvA 172.29.4.156 transform_indexing      0        0         0
VbBadlehSNqlXKtWGlyUvA 172.29.4.156 warmer                  0        0    749996
VbBadlehSNqlXKtWGlyUvA 172.29.4.156 watcher                 0        0     23390
VbBadlehSNqlXKtWGlyUvA 172.29.4.156 write                   0        0  34229769
Py5AN5uKS7OWoDXwdr_ayw 172.29.4.157 analyze                 0        0         0
Py5AN5uKS7OWoDXwdr_ayw 172.29.4.157 ccr                     0        0     70051
Py5AN5uKS7OWoDXwdr_ayw 172.29.4.157 fetch_shard_started     0        0         0
Py5AN5uKS7OWoDXwdr_ayw 172.29.4.157 fetch_shard_store       0        0        34
Py5AN5uKS7OWoDXwdr_ayw 172.29.4.157 flush                   0        0      8912
Py5AN5uKS7OWoDXwdr_ayw 172.29.4.157 force_merge             0        0         0
Py5AN5uKS7OWoDXwdr_ayw 172.29.4.157 generic                 0        0   1688212
Py5AN5uKS7OWoDXwdr_ayw 172.29.4.157 get                     0        0     95389
Py5AN5uKS7OWoDXwdr_ayw 172.29.4.157 listener                0        0     11281
Py5AN5uKS7OWoDXwdr_ayw 172.29.4.157 management              0        0  11715898
Py5AN5uKS7OWoDXwdr_ayw 172.29.4.157 refresh                 0        0  15957993
Py5AN5uKS7OWoDXwdr_ayw 172.29.4.157 rollup_indexing         0        0         0
Py5AN5uKS7OWoDXwdr_ayw 172.29.4.157 search                  0        0    884079
Py5AN5uKS7OWoDXwdr_ayw 172.29.4.157 search_throttled        0        0         0
Py5AN5uKS7OWoDXwdr_ayw 172.29.4.157 security-token-key      0        0         0
Py5AN5uKS7OWoDXwdr_ayw 172.29.4.157 snapshot                0        0         0
Py5AN5uKS7OWoDXwdr_ayw 172.29.4.157 transform_indexing      0        0         0
Py5AN5uKS7OWoDXwdr_ayw 172.29.4.157 warmer                  0        0    482303
Py5AN5uKS7OWoDXwdr_ayw 172.29.4.157 watcher                 0        0     46692
Py5AN5uKS7OWoDXwdr_ayw 172.29.4.157 write                   0        0  50279093
wrKFBPZGQCm9kHxDAe8krw 172.29.4.158 analyze                 0        0         0
wrKFBPZGQCm9kHxDAe8krw 172.29.4.158 ccr                     0        0     70124
wrKFBPZGQCm9kHxDAe8krw 172.29.4.158 fetch_shard_started     0        0         0
wrKFBPZGQCm9kHxDAe8krw 172.29.4.158 fetch_shard_store       0        0        50
wrKFBPZGQCm9kHxDAe8krw 172.29.4.158 flush                   0        0     14722
wrKFBPZGQCm9kHxDAe8krw 172.29.4.158 force_merge             0        0         0
wrKFBPZGQCm9kHxDAe8krw 172.29.4.158 generic                 0        0   1473305
wrKFBPZGQCm9kHxDAe8krw 172.29.4.158 get                     0        0    113200
wrKFBPZGQCm9kHxDAe8krw 172.29.4.158 listener                0        0     12675
wrKFBPZGQCm9kHxDAe8krw 172.29.4.158 management              0        0  27809756
wrKFBPZGQCm9kHxDAe8krw 172.29.4.158 refresh                 0        0  12937481
wrKFBPZGQCm9kHxDAe8krw 172.29.4.158 rollup_indexing         0        0         0
wrKFBPZGQCm9kHxDAe8krw 172.29.4.158 search                  0        0    987998
wrKFBPZGQCm9kHxDAe8krw 172.29.4.158 search_throttled        0        0         0
wrKFBPZGQCm9kHxDAe8krw 172.29.4.158 security-token-key      0        0         0
wrKFBPZGQCm9kHxDAe8krw 172.29.4.158 snapshot                0        0         0
wrKFBPZGQCm9kHxDAe8krw 172.29.4.158 transform_indexing      0        0         0
wrKFBPZGQCm9kHxDAe8krw 172.29.4.158 warmer                  0        0    670607
wrKFBPZGQCm9kHxDAe8krw 172.29.4.158 watcher                 0        0         0
wrKFBPZGQCm9kHxDAe8krw 172.29.4.158 write                   0        0  69187927

 

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