Elasticsearch process memory locking failed - linux

Question

I have set boostrap.memory_lock=true
Updated /etc/security/limits.conf added memlock unlimited for elastic search user
My elastic search was running fine for many months. Suddenly it failed 1 day back. In logs I can see below error and process never starts
ERROR: bootstrap checks failed
memory locking requested for elasticsearch process but memory is not locked
I hit ulimit -as and I can see max locked memory set to unlimited. What is going wrong here? I have been trying for hours but all in vain. Please help.
OS is RHEL 7.2
Elasticsearch 5.1.2
ulimit -as output
core file size (blocks -c) 0
data seg size (kbytes -d) unlimited
scheduling policy (-e) 0
file size (blocks, -f) unlimited
pending signals (-i) 83552
max locked memory (kbytes, -l) unlimited
max memory size (kbytes, -m) unlimited
open files (-n) 65536
pipe size (512 bytes, -q) 8
POSIX message queues (bytes,-q) 819200
real-time priority (-r) 0
stack size kbytes, -s) 8192
cpu time seconds, -t) unlimited
max user processes (-u) 4096
virtual memory (kbytes, -v) unlimited
file locks (-x) unlimited

Answer 1

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 unlimited
elasticsearch 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.

Answer 2

OS = Ubuntu 16
ElasticSearch = 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.
Set in /etc/security/limits.conf
elasticsearch - memlock unlimited
check that for elasticsearch max locked memory is unlimited
$ sudo su elasticsearch -s /bin/bash
$ ulimit -l
disable bootstrap.memory_lock: true in /etc/elasticsearch/elasticsearch.yml
# bootstrap.memory_lock: true
start service elasticsearch via systemd
# service elasticsearch start
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.

Answer 3

try setting
in /etc/sysconfig/elasticsearch file
set MAX_LOCKED_MEMORY=unlimited
in /usr/lib/systemd/system/elasticsearch.service
set LimitMEMLOCK=infinity

Answer 4

Make sure that your elasticsearch start process is configured to unlimited. For if e.g. you start elasticsarch with another user as the one configured in /etc/security/limits.conf or as root while defining a wildcard entry in limits.conf (which is not for root) it won't work.
Test itto be sure:
you could e.g. put ulimit -a ; exit just after the "#Start Daemon" in /etc/init.d/elasticsearch and start with bash /etc/init.d/elasticsearch start (adapt accordingly to your start mechanism).

Answer 5

check for the actual limit when the process is running (albeit short) with:
cat /proc/<pid>/limits
You will find lines similar to this:
Limit Soft Limit Hard Limit Units
Max cpu time unlimited unlimited seconds
Max file size unlimited unlimited bytes
Max data size unlimited unlimited bytes
Max stack size 8388608 unlimited bytes
Max core file size 0 unlimited bytes
<truncated>
Then depend on the runner or container (in my case it was supervisord's minfds value), you can lift the actual limitation configuration.
I hope it gives a little hint for more general cases.

Answer 6

Followed this post
On ubuntu 18.04 with elasticsearch 6.x, there wasn't entry LimitMEMLOCK=infinity in file /usr/lib/systemd/system/elasticsearch.service.
So adding that in that file and setting MAX_LOCKED_MEMORY=unlimited in /etc/default/elasticsearch did the trick.
The jvm options can be added in /etc/elasticsearch/jvm.options file.

Answer 7

If you use the tar distribution and want to monitor it with monit you
have to tell monit to use unlimited - all other places for this configuration are ignored.
Add ulimit -s unlimited at the beginning of /etc/init.d/monit, then do systemctl daemon-reload and then service monit restart and monit start $yourMonitLabel.

Answer 8

One thing it "can" be is that your /tmp is mounted with noexec https://discuss.elastic.co/t/not-able-to-start-elasticsearch-due-to-failed-memory-lock/158009/6 check your logs and see if it complains about .UnsatisfiedLinkError: Native library
especially CentOS/RedHat but maybe others? Might be fixed in ES 7?