Elasticsearch索引分片损坏该怎么办？（二）

岳涛 • 2023-01-02 • 云技术社区 • 478 阅读

说明

本文描述问题及解决方法同样适用于 腾讯云 Elasticsearch Service（ES）。

本文延续上一篇 Elasticsearch索引分片损坏该怎么办？（一）

本文另有延续 Elasticsearch索引分片损坏该怎么办？（三）

背景

  • 前面我们学习了Elasticsearch集群异常状态（RED、YELLOW）原因分析，了解到了当集群发生主分片无法上线的情况下，集群状态会变为RED，此时相应的RED索引读写请求都会受到严重的影响。
  • 这里我们将介绍索引分片损坏这种情况，当索引分片发生损坏时，对应的主分片会无法分配，且状态也会是RED。然而分片的损坏的情况又分为很多种，有些只是表象，可以通过一些手段恢复，但有些则是真实的物理损坏，且无法恢复，只能丢弃部分数据，甚至整块分片。

问题

场景：磁盘故障引起的checksum异常

这种情况也比较常见，一般我们可以通过explain api来确认：

  • [root@sh ~]# curl -s -XGET localhost:9200/_cluster/allocation/explain?pretty

  • {

  •   "index" : "twitter",

  •   "shard" : 0,

  •   "primary" : true,

  •   "current_state" : "unassigned",

  •   "unassigned_info" : {

  •     "reason" : "ALLOCATION_FAILED",

  •     "at" : "2018-11-06T06:11:15.562Z",

  •     "failed_allocation_attempts" : 5,

  •     "details" : "failed shard on node [CxXWE8BiQbS4ThB9AvvGQA]: failed recovery, failure RecoveryFailedException[[t

  • witter][0]: Recovery failed on {node-1}{CxXWE8BiQbS4ThB9AvvGQA}{yYDvXMKnS9KhaIlzPEsJNg}{10.142.0.2}{10.142.0.2:9300

  • }]; nested: IndexShardRecoveryException[failed to recover from gateway]; nested: EngineCreationFailureException[fai

  • led to create engine]; nested: CorruptIndexException[misplaced codec footer (file truncated?): length=0 but footerL

  • ength==16 (resource=SimpleFSIndexInput(path=\\"/var/lib/elasticsearch/nodes/0/indices/l1VcSQySRmuyFGTBBPjX9g/0/trans

  • log/translog-1228.ckp\\"))]; ",

  •     "last_allocation_status" : "no"

  •   },

  •   "can_allocate" : "no",

  •   "allocate_explanation" : "cannot allocate because allocation is not permitted to any of the nodes that hold an in

  • -sync shard copy",

  •   "node_allocation_decisions" : [

  •     {

  •       "node_id" : "CxXWE8BiQbS4ThB9AvvGQA",

  •       "node_name" : "node-1",

  •       "transport_address" : "10.142.0.2:9300",

  •       "node_decision" : "no",

  •       "store" : {

  •         "in_sync" : true,

  •         "allocation_id" : "gxegPAMyQa21MH5NxQEACw"

  •       },

  •       "deciders" : [

  •         {

  •           "decider" : "max_retry",

  •           "decision" : "NO",

  •           "explanation" : "shard has exceeded the maximum number of retries [5] on failed allocation attempts - man

  • ually call [/_cluster/reroute?retry_failed=true] to retry, [unassigned_info[[reason=ALLOCATION_FAILED], at[2018-11-

  • 06T06:11:15.562Z], failed_attempts[5], delayed=false, details[failed shard on node [CxXWE8BiQbS4ThB9AvvGQA]: failed

  •  recovery, failure RecoveryFailedException[[twitter][0]: Recovery failed on {node-1}{CxXWE8BiQbS4ThB9AvvGQA}{yYDvXM

  • KnS9KhaIlzPEsJNg}{10.142.0.2}{10.142.0.2:9300}]; nested: IndexShardRecoveryException[failed to recover from gateway

  • ]; nested: EngineCreationFailureException[failed to create engine]; nested: CorruptIndexException[misplaced codec f

  • ooter (file truncated?): length=0 but footerLength==16 (resource=SimpleFSIndexInput(path=\\"/var/lib/elasticsearch/n

  • odes/0/indices/l1VcSQySRmuyFGTBBPjX9g/0/translog/translog-1228.ckp\\"))]; ], allocation_status[deciders_no]]]"

  •         }

  •       ]

  •     }

  •   ]

  • }

展开

或者通过日志信息来确认：

  • [o.e.a.a.c.a.TransportClusterAllocationExplainAction] [1624264340001550732] explaining the allocation for [ClusterAllocationExplainRequest[index=qw_cust_group,shard=3,primary?=true,includeYesDecisions?=false], found shard [[qw_cust_group][3], node[null], [P], recovery_source[existing recovery], s[UNASSIGNED], unassigned_info[[reason=ALLOCATION_FAILED], at[2021-09-29T07:10:25.054Z], failed_attempts[13], delayed=false, details[failed recovery, failure RecoveryFailedException[[qw_cust_group][3]: Recovery failed on {1624264340001550832}{bbNH-12CS7uy8dYTYAywgQ}{_PqMaYD_T-yz1u67-ifKdQ}{172.23.15.115}{172.23.15.115:9300}{temperature=hot, rack=cvm_8_800007, set=800007, region=8, ip=9.15.112.197}]; nested: IndexShardRecoveryException[failed to recover from gateway]; nested: EngineCreationFailureException[failed to create engine]; nested: CorruptIndexException[misplaced codec footer (file truncated?): length=0 but footerLength==16 (resource=SimpleFSIndexInput(path="/data1/containers/1624264340001550832/es/data/nodes/0/indices/d1_CneTOQcCCgatoDMX8Ag/3/translog/translog-2705.ckp"))]; ], allocation_status[deciders_no]]]

  • [o.e.c.a.s.ShardStateAction] [1624264340001550732] [qw_cust_group][3] received shard failed for shard id [[qw_cust_group][3]], allocation id [HlWMLhDHTDe3hYFjY7oo0g], primary term [0], message [failed recovery], failure [RecoveryFailedException[[qw_cust_group][3]: Recovery failed on {1624264340001550832}{bbNH-12CS7uy8dYTYAywgQ}{_PqMaYD_T-yz1u67-ifKdQ}{172.23.15.115}{172.23.15.115:9300}{temperature=hot, rack=cvm_8_800007, set=800007, region=8, ip=9.15.112.197}]; nested: IndexShardRecoveryException[failed to recover from gateway]; nested: EngineCreationFailureException[failed to create engine]; nested: CorruptIndexException[misplaced codec footer (file truncated?): length=0 but footerLength==16 (resource=SimpleFSIndexInput(path="/data1/containers/1624264340001550832/es/data/nodes/0/indices/d1_CneTOQcCCgatoDMX8Ag/3/translog/translog-2705.ckp"))]; ]

  • org.elasticsearch.indices.recovery.RecoveryFailedException: [qw_cust_group][3]: Recovery failed on {1624264340001550832}{bbNH-12CS7uy8dYTYAywgQ}{_PqMaYD_T-yz1u67-ifKdQ}{172.23.15.115}{172.23.15.115:9300}{temperature=hot, rack=cvm_8_800007, set=800007, region=8, ip=9.15.112.197}

  • 	at org.elasticsearch.index.shard.IndexShard.lambda$startRecovery$1(IndexShard.java:1488) ~[elasticsearch-5.6.4.jar:5.6.4]

  • 	at org.elasticsearch.common.util.concurrent.ThreadContext$ContextPreservingRunnable.run(ThreadContext.java:569) ~[elasticsearch-5.6.4.jar:5.6.4]

  • 	at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source) ~[?:1.8.0_181]

  • 	at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source) ~[?:1.8.0_181]

  • 	at java.lang.Thread.run(Unknown Source) [?:1.8.0_181]

  • Caused by: org.elasticsearch.index.shard.IndexShardRecoveryException: failed to recover from gateway

  • 	at org.elasticsearch.index.shard.StoreRecovery.internalRecoverFromStore(StoreRecovery.java:365) ~[elasticsearch-5.6.4.jar:5.6.4]

  • 	at org.elasticsearch.index.shard.StoreRecovery.lambda$recoverFromStore$0(StoreRecovery.java:90) ~[elasticsearch-5.6.4.jar:5.6.4]

  • 	at org.elasticsearch.index.shard.StoreRecovery.executeRecovery(StoreRecovery.java:257) ~[elasticsearch-5.6.4.jar:5.6.4]

  • 	at org.elasticsearch.index.shard.StoreRecovery.recoverFromStore(StoreRecovery.java:88) ~[elasticsearch-5.6.4.jar:5.6.4]

  • 	at org.elasticsearch.index.shard.IndexShard.recoverFromStore(IndexShard.java:1236) ~[elasticsearch-5.6.4.jar:5.6.4]

  • 	at org.elasticsearch.index.shard.IndexShard.lambda$startRecovery$1(IndexShard.java:1484) ~[elasticsearch-5.6.4.jar:5.6.4]

  • 	... 4 more

  • Caused by: org.elasticsearch.index.engine.EngineCreationFailureException: failed to create engine

  • 	at org.elasticsearch.index.engine.InternalEngine.<init>(InternalEngine.java:163) ~[elasticsearch-5.6.4.jar:5.6.4]

  • 	at org.elasticsearch.index.engine.InternalEngineFactory.newReadWriteEngine(InternalEngineFactory.java:25) ~[elasticsearch-5.6.4.jar:5.6.4]

  • 	at org.elasticsearch.index.shard.IndexShard.newEngine(IndexShard.java:1602) ~[elasticsearch-5.6.4.jar:5.6.4]

  • 	at org.elasticsearch.index.shard.IndexShard.createNewEngine(IndexShard.java:1584) ~[elasticsearch-5.6.4.jar:5.6.4]

  • 	at org.elasticsearch.index.shard.IndexShard.internalPerformTranslogRecovery(IndexShard.java:1027) ~[elasticsearch-5.6.4.jar:5.6.4]

  • 	at org.elasticsearch.index.shard.IndexShard.performTranslogRecovery(IndexShard.java:987) ~[elasticsearch-5.6.4.jar:5.6.4]

  • 	at org.elasticsearch.index.shard.StoreRecovery.internalRecoverFromStore(StoreRecovery.java:360) ~[elasticsearch-5.6.4.jar:5.6.4]

  • 	at org.elasticsearch.index.shard.StoreRecovery.lambda$recoverFromStore$0(StoreRecovery.java:90) ~[elasticsearch-5.6.4.jar:5.6.4]

  • 	at org.elasticsearch.index.shard.StoreRecovery.executeRecovery(StoreRecovery.java:257) ~[elasticsearch-5.6.4.jar:5.6.4]

  • 	at org.elasticsearch.index.shard.StoreRecovery.recoverFromStore(StoreRecovery.java:88) ~[elasticsearch-5.6.4.jar:5.6.4]

  • 	at org.elasticsearch.index.shard.IndexShard.recoverFromStore(IndexShard.java:1236) ~[elasticsearch-5.6.4.jar:5.6.4]

  • 	at org.elasticsearch.index.shard.IndexShard.lambda$startRecovery$1(IndexShard.java:1484) ~[elasticsearch-5.6.4.jar:5.6.4]

  • 	... 4 more

  • Caused by: org.apache.lucene.index.CorruptIndexException: misplaced codec footer (file truncated?): length=0 but footerLength==16 (resource=SimpleFSIndexInput(path="/data1/containers/1624264340001550832/es/data/nodes/0/indices/d1_CneTOQcCCgatoDMX8Ag/3/translog/translog-2705.ckp"))

  • 	at org.apache.lucene.codecs.CodecUtil.checksumEntireFile(CodecUtil.java:523) ~[lucene-core-6.6.1.jar:6.6.1 unknown - boicehuang - 2018-11-20 19:03:10]

  • 	at org.elasticsearch.index.translog.Checkpoint.read(Checkpoint.java:98) ~[elasticsearch-5.6.4.jar:5.6.4]

  • 	at org.elasticsearch.index.translog.Translog.recoverFromFiles(Translog.java:237) ~[elasticsearch-5.6.4.jar:5.6.4]

  • 	at org.elasticsearch.index.translog.Translog.<init>(Translog.java:177) ~[elasticsearch-5.6.4.jar:5.6.4]

  • 	at org.elasticsearch.index.engine.InternalEngine.openTranslog(InternalEngine.java:272) ~[elasticsearch-5.6.4.jar:5.6.4]

  • 	at org.elasticsearch.index.engine.InternalEngine.<init>(InternalEngine.java:160) ~[elasticsearch-5.6.4.jar:5.6.4]

  • 	at org.elasticsearch.index.engine.InternalEngineFactory.newReadWriteEngine(InternalEngineFactory.java:25) ~[elasticsearch-5.6.4.jar:5.6.4]

  • 	at org.elasticsearch.index.shard.IndexShard.newEngine(IndexShard.java:1602) ~[elasticsearch-5.6.4.jar:5.6.4]

  • 	at org.elasticsearch.index.shard.IndexShard.createNewEngine(IndexShard.java:1584) ~[elasticsearch-5.6.4.jar:5.6.4]

  • 	at org.elasticsearch.index.shard.IndexShard.internalPerformTranslogRecovery(IndexShard.java:1027) ~[elasticsearch-5.6.4.jar:5.6.4]

  • 	at org.elasticsearch.index.shard.IndexShard.performTranslogRecovery(IndexShard.java:987) ~[elasticsearch-5.6.4.jar:5.6.4]

  • 	at org.elasticsearch.index.shard.StoreRecovery.internalRecoverFromStore(StoreRecovery.java:360) ~[elasticsearch-5.6.4.jar:5.6.4]

  • 	at org.elasticsearch.index.shard.StoreRecovery.lambda$recoverFromStore$0(StoreRecovery.java:90) ~[elasticsearch-5.6.4.jar:5.6.4]

  • 	at org.elasticsearch.index.shard.StoreRecovery.executeRecovery(StoreRecovery.java:257) ~[elasticsearch-5.6.4.jar:5.6.4]

  • 	at org.elasticsearch.index.shard.StoreRecovery.recoverFromStore(StoreRecovery.java:88) ~[elasticsearch-5.6.4.jar:5.6.4]

  • 	at org.elasticsearch.index.shard.IndexShard.recoverFromStore(IndexShard.java:1236) ~[elasticsearch-5.6.4.jar:5.6.4]

  • 	at org.elasticsearch.index.shard.IndexShard.lambda$startRecovery$1(IndexShard.java:1484) ~[elasticsearch-5.6.4.jar:5.6.4]

  • 	... 4 more

展开

其共同的关键信息都是：file truncated?

解决方案

方案一：REOPEN分片

reopen的目的是触发索引分片重新上线，直接调用_close和_open api即可：

  • [root@sh ~]# curl -s -XPOST localhost:9200/twitter/_close?pretty

  • {

  •   "acknowledged": true

  • }

  • [root@sh ~]# curl -s -XPOST localhost:9200/twitter/_open?pretty

  • {

  •   "acknowledged": true,

  •   "shards_acknowledged": true

  • }

方案二：分配陈腐的分片

如果reopen索引无法使分片上线，则需要考虑使用reroute api分配stale primary。执行这个api之前，我们需要得到一些信息：

  • 索引名称和分片ID可以通过explain api直观看到；
  • 节点名称可以通过unassigned_info.details得到。

根据这些信息，我们就可以执行reroute api了：

  • [root@sh ~]# curl -s -H "Content-Type:application/json" -XPOST "localhost:9200/_cluster/reroute?pretty" -d '

  • {

  •   "commands": [

  •     {

  •       "allocate_stale_primary": {

  •       "index": "{索引名称}",

  •       "shard": "{分片ID}",

  •       "node": "{节点名称}",

  •       "accept_data_loss": true

  •       }

  •     }

  •   ]

  • }

方案三：清理corrupt文件

在故障目录，如果出现corrupt开头的文件，则需要清理掉这个文件。corrupt开头的文件是记录文件损坏的位置，不移除这个文件，分配stale是无法恢复，移除了这个文件才能恢复。清理完corrupt文件之后，再重试方案二。

方案四：丢弃分片（三思！慎用！）

如果分配陈腐的分片也无法使分片上线，为了不影响索引读写请求，就只能丢弃掉损坏的分片了，这是最糟糕的情况：

  • [root@sh ~]# curl -s -H "Content-Type:application/json" -XPOST "localhost:9200/_cluster/reroute?pretty" -d '

  • {

  •     "commands" : [

  •         {

  •           "allocate_empty_primary" : {

  •               "index" : "{索引名称}", 

  •               "shard" : "{分片ID}",

  •               "node" : "{节点名称}",

  •               "accept_data_loss": true

  •           }

  •         }

  •     ]

  • }'
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