Elasticsearch process memory locking failed

Here is what I have done to lock the memory on my ES nodes on RedHat/Centos 7 (it will work on other distributions if they use systemd).

You must make the change in 4 different places:

1) /etc/sysconfig/elasticsearch

On sysconfig: /etc/sysconfig/elasticsearch you should have:

ES_JAVA_OPTS="-Xms4g -Xmx4g" MAX_LOCKED_MEMORY=unlimited

(replace 4g with HALF your available RAM as recommended here)

2) /etc/security/limits.conf

On security limits config: /etc/security/limits.conf you should have

elasticsearch soft memlock unlimitedelasticsearch hard memlock unlimited

3) /usr/lib/systemd/system/elasticsearch.service

On the service script: /usr/lib/systemd/system/elasticsearch.service you should uncomment:

LimitMEMLOCK=infinity

you should do systemctl daemon-reload after changing the service script

4) /etc/elasticsearch/elasticsearch.yml

On elasticsearch config finally: /etc/elasticsearch/elasticsearch.yml you should add:

bootstrap.memory_lock: true

Thats it, restart your node and the RAM will be locked, you should notice a major performance improvement.

OS = Ubuntu 16ElasticSearch = 5.6.3

I also used to have the same problem.

I set in elasticsearch.yml

bootstrap.memory_lock: true

and i got in my logs:

memory locking requested for elasticsearch process but memory is not locked

i tried several things, but actually you need to do only one thing (according to https://www.elastic.co/guide/en/elasticsearch/reference/master/setting-system-settings.html );

file:

/etc/systemd/system/elasticsearch.service.d/override.conf

add

[Service]LimitMEMLOCK=infinity

A little bit explanation.

The really funny thing is that systemd does not really care about ulimit settings at all. ( https://fredrikaverpil.github.io/2016/04/27/systemd-and-resource-limits/ ). You can easily check this fact.

1. Set in /etc/security/limits.conf

   elasticsearch - memlock unlimited

2. check that for elasticsearch max locked memory is unlimited

   $ sudo su elasticsearch -s /bin/bash$ ulimit -l

3. disable bootstrap.memory_lock: true in /etc/elasticsearch/elasticsearch.yml

   # bootstrap.memory_lock: true

4. start service elasticsearch via systemd

   # service elasticsearch start

5. check what max memory lock settings has service elasticsearch after it is started

   # systemctl show elasticsearch | grep -i limitmemlock

OMG! In spite we have set unlimited max memlock size via ulimit , systemd completely ignores it.

LimitMEMLOCK=65536

So, we come to conclusion.To start elasticsearch via systemd with enabled

bootstrap.memory_lock: true

we dont need to care about ulimit settings but we need explecitely set it in systemd config file.

the end of story.

try setting in /etc/sysconfig/elasticsearch fileset MAX_LOCKED_MEMORY=unlimited

in /usr/lib/systemd/system/elasticsearch.serviceset LimitMEMLOCK=infinity