141 lines
4.8 KiB
Plaintext
141 lines
4.8 KiB
Plaintext
[[setting-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
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install Elasticsearch, and which operating system you are using.
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When using the `.zip` or `.tar.gz` packages, system settings can be configured:
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* temporarily with <<ulimit,`ulimit`>>, or
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* permanently in <<limits.conf,`/etc/security/limits.conf`>>.
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When using the RPM or Debian packages, most system settings are set in the
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<<sysconfig,system configuration file>>. However, systems which use systemd
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require that system limits are specified in a
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<<systemd,systemd configuration file>>.
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[[ulimit]]
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==== `ulimit`
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On Linux systems, `ulimit` can be used to change resource limits on a
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temporary basis. Limits usually need to be set as `root` before switching to
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the user that will run Elasticsearch. For example, to set the number of
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open file handles (`ulimit -n`) to 65,536, you can do the following:
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[source,sh]
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--------------------------------
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sudo su <1>
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ulimit -n 65536 <2>
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su elasticsearch <3>
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--------------------------------
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<1> Become `root`.
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<2> Change the max number of open files.
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<3> Become the `elasticsearch` user in order to start Elasticsearch.
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The new limit is only applied during the current session.
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You can consult all currently applied limits with `ulimit -a`.
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[[limits.conf]]
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==== `/etc/security/limits.conf`
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On Linux systems, persistent limits can be set for a particular user by
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editing the `/etc/security/limits.conf` file. To set the maximum number of
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open files for the `elasticsearch` user to 65,536, add the following line to
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the `limits.conf` file:
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[source,sh]
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--------------------------------
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elasticsearch - nofile 65536
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--------------------------------
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This change will only take effect the next time the `elasticsearch` user opens
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a new session.
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[NOTE]
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.Ubuntu and `limits.conf`
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===============================
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Ubuntu ignores the `limits.conf` file for processes started by `init.d`. To
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enable the `limits.conf` file, edit `/etc/pam.d/su` and uncomment the
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following line:
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[source,sh]
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--------------------------------
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# session required pam_limits.so
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--------------------------------
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===============================
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[[sysconfig]]
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==== Sysconfig file
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When using the RPM or Debian packages, system settings and environment
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variables can be specified in the system configuration file, which is located
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in:
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[horizontal]
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RPM:: `/etc/sysconfig/elasticsearch`
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Debian:: `/etc/default/elasticsearch`
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However, for systems which uses `systemd`, system limits need to be specified
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via <<systemd,systemd>>.
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[[systemd]]
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==== Systemd configuration
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When using the RPM or Debian packages on systems that use
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https://en.wikipedia.org/wiki/Systemd[systemd], system limits must be
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specified via systemd.
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The systemd service file (`/usr/lib/systemd/system/elasticsearch.service`)
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contains the limits that are applied by default.
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To override these, add a file called
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`/etc/systemd/system/elasticsearch.service.d/elasticsearch.conf` and specify
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any changes in that file, such as:
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[source,sh]
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---------------------------------
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[Service]
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LimitMEMLOCK=infinity
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---------------------------------
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[[jvm-options]]
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==== Setting JVM options
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The preferred method of setting Java Virtual Machine options (including
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system properties and JVM flags) is via the `jvm.options` configuration
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file. The default location of this file is `config/jvm.options` (when
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installing from the tar or zip distributions) and
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`/etc/elasticsearch/jvm.options` (when installing from the Debian or RPM
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packages). This file contains a line-delimited list of JVM arguments,
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which must begin with `-`. You can add custom JVM flags to this file and
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check this configuration into your version control system.
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An alternative mechanism for setting Java Virtual Machine options is
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via the `ES_JAVA_OPTS` environment variable. For instance:
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[source,sh]
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---------------------------------
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export ES_JAVA_OPTS="$ES_JAVA_OPTS -Djava.io.tmpdir=/path/to/temp/dir"
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./bin/elasticsearch
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---------------------------------
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When using the RPM or Debian packages, `ES_JAVA_OPTS` can be specified in the
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<<sysconfig,system configuration file>>.
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The JVM has a built-in mechanism for observing the `JAVA_TOOL_OPTIONS`
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environment variable. We intentionally ignore this environment variable in our
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packaging scripts. The primary reason for this is that on some OS (e.g., Ubuntu)
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there are agents installed by default via this environment variable that we do
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not want interfering with Elasticsearch.
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Additionally, some other Java programs support the `JAVA_OPTS` environment
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variable. This is *not* a mechanism built into the JVM but instead a convention
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in the ecosystem. However, we do not support this environment variable, instead
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supporting setting JVM options via the `jvm.options` file or the environment
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variable `ES_JAVA_OPTS` as above.
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