Checking Elasticsearch Heap Size

Question

How can I check the heap size that is assigned to Elasticsearch engine, is there a way to check it using URL API ? And can I use NEST to check it?

Thanks

Answer 1

In a clustered environment, heap settings can be queried as :

curl -sS  "localhost:9200/_cat/nodes?h=heap*&v"

Eg:

curl -sS  "localhost:9200/_cat/nodes?h=heap*&v"
heap.current heap.percent heap.max
     321.1mb           32  989.8mb
     424.1mb           42  989.8mb
     280.3mb           28  989.8mb

This can also be checked from the ps results, though it will only shed light on the min-max values.

~#ps aux | grep --color=auto -i Xms
elastic  6020  0.0  0.0  12788   936 pts/4    S+   04:24   0:00 grep --color=auto -i Xms elastic+  7218
0.6  9.5 5001220 1565112 ?     Ssl  Jun24   5:14 /usr/bin/java -Xms1g -Xmx1g -XX:+UseConcMarkSweepGC -XX:CMSInitiatingOccupancyFraction=75 -XX:+UseCMSInitiatingOccupancyOnly -XX:+AlwaysPreTouch -Xss1m -Djava.awt.headless=true -Dfile.encoding=UTF-8 -Djna.nosys=true -XX:-OmitStackTraceInFastThrow -Dio.netty.noUnsafe=true -Dio.netty.noKeySetOptimization=true -Dio.netty.recycler.maxCapacityPerThread=0 -Dlog4j.shutdownHookEnabled=false -Dlog4j2.disable.jmx=true -Djava.io.tmpdir=/tmp/elasticsearch.WoiU4NhH -XX:+HeapDumpOnOutOfMemoryError -XX:HeapDumpPath=/var/lib/elasticsearch -XX:ErrorFile=/var/log/elasticsearch/hs_err_pid%p.log -XX:+PrintGCDetails -XX:+PrintGCDateStamps -XX:+PrintTenuringDistribution -XX:+PrintGCApplicationStoppedTime -Xloggc:/var/log/elasticsearch/gc.log -XX:+UseGCLogFileRotation -XX:NumberOfGCLogFiles=32 -XX:GCLogFileSize=64m -Xms1g -Xmx1g -Des.path.home=/usr/share/elasticsearch -Des.path.conf=/etc/elasticsearch -Des.distribution.flavor=default -Des.distribution.type=deb -cp /usr/share/elasticsearch/lib/* org.elasticsearch.bootstrap.Elasticsearch -p /var/run/elasticsearch/elasticsearch.pid --quiet

where -Xms is the minheap and -Xmx is maxheap configured.