Elasticsearch: mulai ulang node setelah java.lang.OutOfMemoryError: ruang heap Java

Question

Salah satu node ES saya gagal karena java.lang.OutOfMemoryError: Java heap spacekesalahan. Berikut adalah pelacakan tumpukan lengkap dari log:

    [2020-09-18T04:25:04,215][WARN ][o.e.a.b.TransportShardBulkAction] [search1] [[my_index_4][0]] failed to perform indices:data/write/bulk[s] on replica [my_index_4][0], node[cm_76wfGRFm9nbPR1mJxTQ], [R], s[STARTED], a[id=BUpviwHxQK2qC3GrELC2Hw]
org.elasticsearch.transport.NodeDisconnectedException: [search3][X.X.X.179:9300][indices:data/write/bulk[s][r]] disconnected
[2020-09-18T04:25:04,215][WARN ][o.e.c.a.s.ShardStateAction] [search1] [my_index_4][0] received shard failed for shard id [[my_index_4][0]], allocation id [BUpviwHxQK2qC3GrELC2Hw], primary term [2], message [failed to perform indices:data/write/bulk[s] on replica [my_index_4][0], node[cm_76wfGRFm9nbPR1mJxTQ], [R], s[STARTED], a[id=BUpviwHxQK2qC3GrELC2Hw]], failure [NodeDisconnectedException[[search3][X.X.X.179:9300][indices:data/write/bulk[s][r]] disconnected]]
org.elasticsearch.transport.NodeDisconnectedException: [search3][X.X.X.179:9300][indices:data/write/bulk[s][r]] disconnected
[2020-09-18T04:25:04,215][DEBUG][o.e.a.a.c.n.i.TransportNodesInfoAction] [search1] failed to execute on node [cm_76wfGRFm9nbPR1mJxTQ]
org.elasticsearch.transport.NodeDisconnectedException: [search3][X.X.X.179:9300][cluster:monitor/nodes/info[n]] disconnected
[2020-09-18T04:25:04,219][INFO ][o.e.c.r.a.AllocationService] [search1] Cluster health status changed from [GREEN] to [YELLOW] (reason: [shards failed [[my_index_4][0]] ...]).
[2020-09-18T04:25:05,450][INFO ][o.e.m.j.JvmGcMonitorService] [search1] [gc][11099506] overhead, spent [605ms] collecting in the last [1.4s]
[2020-09-18T04:25:05,453][ERROR][o.e.b.ElasticsearchUncaughtExceptionHandler] [search1] fatal error in thread [elasticsearch[search1][search][T#5]], exiting
java.lang.OutOfMemoryError: Java heap space
at org.elasticsearch.search.aggregations.bucket.composite.CompositeValuesSource$GlobalOrdinalValuesSource.<init>(CompositeValuesSource.java:137) ~[elasticsearch-6.2.4.jar:6.2.4] at org.elasticsearch.search.aggregations.bucket.composite.CompositeValuesSource.wrapGlobalOrdinals(CompositeValuesSource.java:123) ~[elasticsearch-6.2.4.jar:6.2.4] at org.elasticsearch.search.aggregations.bucket.composite.CompositeValuesComparator.<init>(CompositeValuesComparator.java:50) ~[elasticsearch-6.2.4.jar:6.2.4] at org.elasticsearch.search.aggregations.bucket.composite.CompositeAggregator.<init>(CompositeAggregator.java:69) ~[elasticsearch-6.2.4.jar:6.2.4] at org.elasticsearch.search.aggregations.bucket.composite.CompositeAggregationFactory.createInternal(CompositeAggregationFactory.java:52) ~[elasticsearch-6.2.4.jar:6.2.4] at org.elasticsearch.search.aggregations.AggregatorFactory.create(AggregatorFactory.java:216) ~[elasticsearch-6.2.4.jar:6.2.4] at org.elasticsearch.search.aggregations.AggregatorFactories.createTopLevelAggregators(AggregatorFactories.java:216) ~[elasticsearch-6.2.4.jar:6.2.4] at org.elasticsearch.search.aggregations.AggregationPhase.preProcess(AggregationPhase.java:55) ~[elasticsearch-6.2.4.jar:6.2.4] at org.elasticsearch.search.query.QueryPhase.execute(QueryPhase.java:105) ~[elasticsearch-6.2.4.jar:6.2.4] at org.elasticsearch.indices.IndicesService.lambda$loadIntoContext$14(IndicesService.java:1133) ~[elasticsearch-6.2.4.jar:6.2.4] at org.elasticsearch.indices.IndicesService$$Lambda$2241/341562582.accept(Unknown Source) ~[?:?] at org.elasticsearch.indices.IndicesService.lambda$cacheShardLevelResult$15(IndicesService.java:1186) ~[elasticsearch-6.2.4.jar:6.2.4] at org.elasticsearch.indices.IndicesService$$Lambda$2242/1286052129.get(Unknown Source) ~[?:?] at org.elasticsearch.indices.IndicesRequestCache$Loader.load(IndicesRequestCache.java:160) ~[elasticsearch-6.2.4.jar:6.2.4]
at org.elasticsearch.indices.IndicesRequestCache$Loader.load(IndicesRequestCache.java:143) ~[elasticsearch-6.2.4.jar:6.2.4] at org.elasticsearch.common.cache.Cache.computeIfAbsent(Cache.java:412) ~[elasticsearch-6.2.4.jar:6.2.4] at org.elasticsearch.indices.IndicesRequestCache.getOrCompute(IndicesRequestCache.java:116) ~[elasticsearch-6.2.4.jar:6.2.4] at org.elasticsearch.indices.IndicesService.cacheShardLevelResult(IndicesService.java:1192) ~[elasticsearch-6.2.4.jar:6.2.4] at org.elasticsearch.indices.IndicesService.loadIntoContext(IndicesService.java:1132) ~[elasticsearch-6.2.4.jar:6.2.4] at org.elasticsearch.search.SearchService.loadOrExecuteQueryPhase(SearchService.java:305) ~[elasticsearch-6.2.4.jar:6.2.4] at org.elasticsearch.search.SearchService.executeQueryPhase(SearchService.java:340) ~[elasticsearch-6.2.4.jar:6.2.4] at org.elasticsearch.search.SearchService$2.onResponse(SearchService.java:316) ~[elasticsearch-6.2.4.jar:6.2.4]
at org.elasticsearch.search.SearchService$2.onResponse(SearchService.java:312) ~[elasticsearch-6.2.4.jar:6.2.4] at org.elasticsearch.search.SearchService$3.doRun(SearchService.java:1002) ~[elasticsearch-6.2.4.jar:6.2.4]
at org.elasticsearch.common.util.concurrent.ThreadContext$ContextPreservingAbstractRunnable.doRun(ThreadContext.java:672) ~[elasticsearch-6.2.4.jar:6.2.4] at org.elasticsearch.common.util.concurrent.AbstractRunnable.run(AbstractRunnable.java:37) ~[elasticsearch-6.2.4.jar:6.2.4] at org.elasticsearch.common.util.concurrent.TimedRunnable.doRun(TimedRunnable.java:41) ~[elasticsearch-6.2.4.jar:6.2.4] at org.elasticsearch.common.util.concurrent.AbstractRunnable.run(AbstractRunnable.java:37) ~[elasticsearch-6.2.4.jar:6.2.4] at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149) ~[?:1.8.0_171] at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) ~[?:1.8.0_171]
at java.lang.Thread.run(Thread.java:748) [?:1.8.0_171]

Karena pengecualian di atas, saya dapatkan master_not_discovered_exceptionsaat menggunakan ES API mana pun.

Pertanyaan : Adakah yang bisa memberi tahu saya langkah selanjutnya yang harus saya lakukan untuk mengembalikan Elasticsearch ke keadaan normal? Apakah ada cara untuk memulai kembali node yang terputus?

Answer 1

Pertama izinkan saya menjelaskan secara singkat apa yang mungkin menyebabkan masalah ini:

1. Seperti yang disebutkan dalam log, Anda tampaknya menjalankan agregasi yang mahal, yang pada umumnya intensif memori dan diketahui menghabiskan banyak memori, yang tidak dapat diperoleh kembali oleh koleksi Sampah (GC) Anda, dan akhirnya aplikasi Anda (ES) berjalan kehabisan memori dan terbunuh.
2. Terlepas dari agregasi mahal yang ditampilkan di log, konsumsi memori yang tinggi juga dapat disebabkan oleh pencarian yang berat dan permintaan pengindeksan, jadi silakan lihat pencarian dan indeks log lambat node ini, lihat log lambat ES untuk info lebih lanjut

Sekarang sampai pada bagian resolusi

Node ES ini sudah mati, yang menyebabkan master_not_discovered_exceptionkarenanya penting untuk memulai ulang node ini lagi dan melihat apakah pengecualian ini berjalan. Lihat blog opster ini untuk membaca lebih lanjut tentang pengecualian ini .

Pencegahan pengecualian OOM

1. Anda harus mengonfigurasi pemutus sirkuit yang tersedia di ES dengan benar dan jika memungkinkan meningkatkan ke ES 7.X yang memiliki pemutus sirkuit yang lebih baik berdasarkan memori nyata
2. Tingkatkan pengindeksan ES dan kinerja pencarian .

Answer 2

Ini java.lang.OutOfMemoryError: Java heap spacedisebabkan oleh menjalankan kueri agregasi gabungan yang sizeparameternya saya setel ke Integer.MAX_VALUE:

{
    "size": 0,

    "aggregations": {
        "myParam.keyword": {
            "composite": {
                "size": 2147483647,
                "sources": [
                    {
                        "myParam.keyword": {
                            "terms": {
                                "field": "myParam.keyword",
                                "order": "asc"
                            }
                        }
                    }
                ]
            }
        }
    }
} 

Menurut pelacakan tumpukan, kesalahan terjadi saat inisialisasi larik nilai agregasi CompositeValuesSource.java:137:

GlobalOrdinalValuesSource(ValuesSource.Bytes.WithOrdinals vs, int size, int reverseMul) {
    super(vs, size, reverseMul);
    this.values = new long[size];
}

Di sini, sizeparameter berasal dari kueri.

Jawabannya https://stackoverflow.com/a/63965634/5284890 mengkonfirmasi akar penyebabnya.

Langkah saya selanjutnya adalah berhenti dan menjalankan Elasticsearcch lagi menggunakan perintah berikut

sudo systemctl stop elasticsearch.service
sudo systemctl start elasticsearch.service

Langkah-langkah berikut adalah memeriksa pemutus sirkuit yang disarankan dalam artikel ES yang disebutkan dalam jawaban ini https://stackoverflow.com/a/63965634/5284890.