[[setup-service]]
== Running as a Service on Linux

In order to run elasticsearch as a service on your operating system, the provided packages try to make it as easy as possible for you to start and stop elasticsearch during reboot and upgrades.

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=== Linux

Currently our build automatically creates a debian package and an RPM package, which is available on the download page. The package itself does not have any dependencies, but you have to make sure that you installed a JDK.

Each package features a configuration file, which allows you to set the following parameters

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`ES_USER`::               The user to run as, defaults to `elasticsearch`
`ES_GROUP`::              The group to run as, defaults to `elasticsearch`
`ES_HEAP_SIZE`::          The heap size to start with
`ES_HEAP_NEWSIZE`::       The size of the new generation heap
`ES_DIRECT_SIZE`::        The maximum size of the direct memory
`MAX_OPEN_FILES`::        Maximum number of open files, defaults to `65535`
`MAX_LOCKED_MEMORY`::     Maximum locked memory size. Set to "unlimited" if you use the bootstrap.mlockall option in elasticsearch.yml. You must also set ES_HEAP_SIZE.
`MAX_MAP_COUNT`::         Maximum number of memory map areas a process may have. If you use `mmapfs` as index store type, make sure this is set to a high value. For more information, check the https://github.com/torvalds/linux/blob/master/Documentation/sysctl/vm.txt[linux kernel documentation] about `max_map_count`. This is set via `sysctl` before starting elasticsearch. Defaults to `65535`
`LOG_DIR`::               Log directory, defaults to `/var/log/elasticsearch`
`DATA_DIR`::              Data directory, defaults to `/var/lib/elasticsearch`
`CONF_DIR`::              Configuration file directory (which needs to include `elasticsearch.yml` and `logging.yml` files), defaults to `/etc/elasticsearch`
`ES_JAVA_OPTS`::          Any additional java options you may want to apply. This may be useful, if you need to set the `node.name` property, but do not want to change the `elasticsearch.yml` configuration file, because it is distributed via a provisioning system like puppet or chef. Example: `ES_JAVA_OPTS="-Des.node.name=search-01"`
`RESTART_ON_UPGRADE`::    Configure restart on package upgrade, defaults to `false`. This means you will have to restart your elasticsearch instance after installing a package manually. The reason for this is to ensure, that upgrades in a cluster do not result in a continuous shard reallocation resulting in high network traffic and reducing the response times of your cluster.
`ES_GC_LOG_FILE` ::       The absolute log file path for creating a garbage collection logfile, which is done by the JVM. Note that this logfile can grow pretty quick and thus is disabled by default.

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==== Debian/Ubuntu

The debian package ships with everything you need as it uses standard debian tools like update `update-rc.d` to define the runlevels it runs on. The init script is placed at `/etc/init.d/elasticsearch` as you would expect it. The configuration file is placed at `/etc/default/elasticsearch`.

The debian package does not start up the service by default. The reason for this is to prevent the instance to accidentally join a cluster, without being configured appropriately. After installing using `dpkg -i` you can use the following commands to ensure, that elasticsearch starts when the system is booted and then start up elasticsearch:

[source,sh]
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sudo update-rc.d elasticsearch defaults 95 10
sudo /etc/init.d/elasticsearch start
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Users running Debian 8 or Ubuntu 14 or later may require configuration of systemd instead of `update-rc.d`. In those cases, please refer to the <<using-systemd>> section.

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===== Installing the oracle JDK

The usual recommendation is to run the Oracle JDK with elasticsearch. However Ubuntu and Debian only ship the OpenJDK due to license issues. You can easily install the oracle installer package though. In case you are missing the `add-apt-repository` command under Debian GNU/Linux, make sure have at least Debian Jessie and the package `python-software-properties` installed

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sudo add-apt-repository ppa:webupd8team/java
sudo apt-get update
sudo apt-get install oracle-java8-installer
java -version
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The last command should verify a successful installation of the Oracle JDK.


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==== RPM based distributions

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===== Using chkconfig

Some RPM based distributions are using `chkconfig` to enable and disable services. The init script is located at `/etc/init.d/elasticsearch`, where as the configuration file is placed at `/etc/sysconfig/elasticsearch`. Like the debian package the RPM package is not started by default after installation, you have to do this manually by entering the following commands

[source,sh]
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sudo /sbin/chkconfig --add elasticsearch
sudo service elasticsearch start
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[[using-systemd]]
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==== Using systemd

Distributions like Debian Jessie, Ubuntu 14, and many of the SUSE derivatives do not use the `chkconfig` tool to register services, but rather `systemd` and its command `/bin/systemctl` to start and stop services (at least in newer versions, otherwise use the `chkconfig` commands above). The configuration file is also placed at `/etc/sysconfig/elasticsearch` if the system is rpm based and `/etc/default/elasticsearch` if it is deb. After installing the RPM, you have to change the systemd configuration and then start up elasticsearch

[source,sh]
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sudo /bin/systemctl daemon-reload
sudo /bin/systemctl enable elasticsearch.service
sudo /bin/systemctl start elasticsearch.service
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Also note that changing the `MAX_MAP_COUNT` setting in `/etc/sysconfig/elasticsearch` does not have any effect, you will have to change it in `/usr/lib/sysctl.d/elasticsearch.conf` in order to have it applied at startup.
