APT/YUM repository URL changesedit

The repository for apt and yum packages has changed from to

Full details can be found in Installing Elasticsearch.

Default logging using systemd (since Elasticsearch 2.2.0)edit

In previous versions of Elasticsearch, the default logging configuration routed standard output to /dev/null and standard error to the journal. However, there are often critical error messages at startup that are logged to standard output rather than standard error and these error messages would be lost to the nether. The default has changed to now route standard output to the journal and standard error to inherit this setting (these are the defaults for systemd). These settings can be modified by editing the elasticsearch.service file.

Longer startup timesedit

In Elasticsearch 5.0.0 the -XX:+AlwaysPreTouch flag has been added to the JVM startup options. This option touches all memory pages used by the JVM heap during initialization of the HotSpot VM to reduce the chance of having to commit a memory page during GC time. This will increase the startup time of Elasticsearch as well as increasing the initial resident memory usage of the Java process.

JVM optionsedit

Arguments to the Java Virtual Machine have been centralized and moved to a new configuration file jvm.options. This centralization allows for simpler end-user management of JVM options.

This migration removes all previous mechanisms of setting JVM options via the environment variables ES_MIN_MEM, ES_MAX_MEM, ES_HEAP_SIZE, ES_HEAP_NEWSIZE, ES_DIRECT_SIZE, ES_USE_IPV4, ES_GC_OPTS, ES_GC_LOG_FILE, and JAVA_OPTS.

The default location for this file is in config/jvm.options if installing from the tar or zip distributions, and /etc/elasticsearch/jvm.options if installing from the Debian or RPM packages. You can specify an alternative location by setting the environment variable ES_JVM_OPTIONS to the path to the file.

Thread stack size for the Windows serviceedit

Previously when installing the Windows service, the installation script would configure the thread stack size (this is required for the service daemon). As a result of moving all JVM configuration to the jvm.options file, the service installation script no longer configures the thread stack size. When installing the Windows service, you must configure thread stack size. For additional details, see the installation docs.

/bin/bash is now requirededit

Previously, the scripts used to start Elasticsearch and run plugin commands only required a Bourne-compatible shell. Starting in Elasticsearch 5.0.0, the bash shell is now required and /bin/bash is a hard-dependency for the RPM and Debian packages.

Environmental Settingsedit

Previously, Elasticsearch could be configured via environment variables in two ways: first by using the placeholder syntax ${env.ENV_VAR_NAME} and the second by using the same syntax without the env prefix: ${ENV_VAR_NAME}. The first method has been removed from Elasticsearch.

Additionally, it was previously possible to set any setting in Elasticsearch via JVM system properties. This has been removed from Elasticsearch.

Dying on fatal errorsedit

Previous versions of Elasticsearch would not halt the JVM if out of memory errors or other fatal errors were encountered during the life of the Elasticsearch instance. Because such errors leave the JVM in a questionable state, the best course of action is to halt the JVM when this occurs. Starting in Elasticsearch 5.x, this is now the case. Operators should consider configuring their Elasticsearch services so that they respawn automatically in the case of such a fatal crash.