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Elastic Docs ›Elasticsearch Reference [5.4] ›Setup Elasticsearch ›Important System Configuration

Configuring system settings

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Configuring system settings

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Where to configure systems settings depends on which package you have used to install Elasticsearch, and which operating system you are using.

When using the .zip or .tar.gz packages, system settings can be configured:

When using the RPM or Debian packages, most system settings are set in the system configuration file. However, systems which use systemd require that system limits are specified in a systemd configuration file.

ulimit

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On Linux systems, ulimit can be used to change resource limits on a temporary basis. Limits usually need to be set as root before switching to the user that will run Elasticsearch. For example, to set the number of open file handles (ulimit -n) to 65,536, you can do the following:

sudo su  
ulimit -n 65536 
su elasticsearch

Become root.

Change the max number of open files.

Become the elasticsearch user in order to start Elasticsearch.

The new limit is only applied during the current session.

You can consult all currently applied limits with ulimit -a.

/etc/security/limits.conf

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On Linux systems, persistent limits can be set for a particular user by editing the /etc/security/limits.conf file. To set the maximum number of open files for the elasticsearch user to 65,536, add the following line to the limits.conf file:

elasticsearch  -  nofile  65536

This change will only take effect the next time the elasticsearch user opens a new session.

Ubuntu and limits.conf

Ubuntu ignores the limits.conf file for processes started by init.d. To enable the limits.conf file, edit /etc/pam.d/su and uncomment the following line:

# session    required   pam_limits.so

Sysconfig file

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When using the RPM or Debian packages, system settings and environment variables can be specified in the system configuration file, which is located in:

RPM

/etc/sysconfig/elasticsearch

Debian

/etc/default/elasticsearch

However, for systems which uses systemd, system limits need to be specified via systemd.

Systemd configuration

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When using the RPM or Debian packages on systems that use systemd, system limits must be specified via systemd.

The systemd service file (/usr/lib/systemd/system/elasticsearch.service) contains the limits that are applied by default.

To override these, add a file called /etc/systemd/system/elasticsearch.service.d/elasticsearch.conf and specify any changes in that file, such as:

[Service]
LimitMEMLOCK=infinity

Setting JVM options

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The preferred method of setting Java Virtual Machine options (including system properties and JVM flags) is via the jvm.options configuration file. The default location of this file is config/jvm.options (when installing from the tar or zip distributions) and /etc/elasticsearch/jvm.options (when installing from the Debian or RPM packages). This file contains a line-delimited list of JVM arguments, which must begin with -. You can add custom JVM flags to this file and check this configuration into your version control system.

An alternative mechanism for setting Java Virtual Machine options is via the ES_JAVA_OPTS environment variable. For instance:

export ES_JAVA_OPTS="$ES_JAVA_OPTS -Djava.io.tmpdir=/path/to/temp/dir"
./bin/elasticsearch

When using the RPM or Debian packages, ES_JAVA_OPTS can be specified in the system configuration file.

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