[[docker]]
=== Install Elasticsearch with Docker

Elasticsearch is also available as a Docker image.
The image is built with {xpack}/index.html[X-Pack].

==== Security note

NOTE: {xpack}/index.html[X-Pack] is preinstalled in this image.
Please take a few minutes to familiarize yourself with {xpack}/security-getting-started.html[X-Pack Security] and how to change default passwords. The default password for the `elastic` user is `changeme`.

NOTE: X-Pack includes a trial license for 30 days. After that, you can obtain one of the https://www.elastic.co/subscriptions[available subscriptions] or {xpack}/security-settings.html[disable Security]. The Basic license is free and includes the https://www.elastic.co/products/x-pack/monitoring[Monitoring] extension.

Obtaining Elasticsearch for Docker is as simple as issuing a +docker pull+ command against the Elastic Docker registry.

ifeval::["{release-state}"=="unreleased"]

WARNING: Version {version} of Elasticsearch has not yet been released, so no Docker image is currently available for this version.

endif::[]

ifeval::["{release-state}"!="unreleased"]

The Docker image can be retrieved with the following command:

["source","sh",subs="attributes"]
--------------------------------------------
docker pull {docker-image}
--------------------------------------------

endif::[]

[[docker-cli-run]]
==== Running Elasticsearch from the command line

[[docker-cli-run-dev-mode]]
===== Development mode

ifeval::["{release-state}"=="unreleased"]

WARNING: Version {version} of the Elasticsearch Docker image has not yet been released.

endif::[]

ifeval::["{release-state}"!="unreleased"]

Elasticsearch can be quickly started for development or testing use with the following command:

["source","sh",subs="attributes"]
--------------------------------------------
docker run -p 9200:9200 -e "http.host=0.0.0.0" -e "transport.host=127.0.0.1" {docker-image}
--------------------------------------------

endif::[]

[[docker-cli-run-prod-mode]]
===== Production mode

[[docker-prod-prerequisites]]
[IMPORTANT]
=========================

The `vm_max_map_count` kernel setting needs to be set to at least `262144` for production use.
Depending on your platform:

* Linux
+
The `vm_map_max_count` setting should be set permanently in /etc/sysctl.conf:
+
[source,sh]
--------------------------------------------
$ grep vm.max_map_count /etc/sysctl.conf
vm.max_map_count=262144
----------------------------------
+
To apply the setting on a live system type: `sysctl -w vm.max_map_count=262144`
+
* OSX with https://docs.docker.com/engine/installation/mac/#/docker-for-mac[Docker for Mac]
+
The `vm_max_map_count` setting must be set within the xhyve virtual machine:
+
["source","sh"]
--------------------------------------------
$ screen ~/Library/Containers/com.docker.docker/Data/com.docker.driver.amd64-linux/tty
--------------------------------------------
+
Log in with 'root' and no password.
Then configure the `sysctl` setting as you would for Linux:
+
["source","sh"]
--------------------------------------------
sysctl -w vm.max_map_count=262144
--------------------------------------------
+
* OSX with https://docs.docker.com/engine/installation/mac/#docker-toolbox[Docker Toolbox]
+
The `vm_max_map_count` setting must be set via docker-machine:
+
["source","sh"]
--------------------------------------------
docker-machine ssh
sudo sysctl -w vm.max_map_count=262144
--------------------------------------------
=========================

The following example brings up a cluster comprising two Elasticsearch nodes.
To bring up the cluster, use the <<docker-prod-cluster-composefile,`docker-compose.yml`>> and just type:

ifeval::["{release-state}"=="unreleased"]

WARNING: Version {version} of the Elasticsearch Docker image has not yet been released, so a `docker-compose.yml` is not available for this version.

endif::[]

ifeval::["{release-state}"!="unreleased"]

["source","sh"]
--------------------------------------------
docker-compose up
--------------------------------------------

endif::[]

[NOTE]
`docker-compose` is not pre-installed with Docker on Linux.
Instructions for installing it can be found on the https://docs.docker.com/compose/install/#install-using-pip[docker-compose webpage].

The node `elasticsearch1` listens on `localhost:9200` while `elasticsearch2` talks to `elasticsearch1` over a Docker network.

This example also uses https://docs.docker.com/engine/tutorials/dockervolumes[Docker named volumes], called `esdata1` and `esdata2` which will be created if not already present.

[[docker-prod-cluster-composefile]]
`docker-compose.yml`:
ifeval::["{release-state}"=="unreleased"]

WARNING: Version {version} of the Elasticsearch Docker image has not yet been released, so a `docker-compose.yml` is not available for this version.

endif::[]

ifeval::["{release-state}"!="unreleased"]
["source","yaml",subs="attributes"]
--------------------------------------------
version: '2'
services:
  elasticsearch1:
    image: docker.elastic.co/elasticsearch/elasticsearch:{version}
    container_name: elasticsearch1
    environment:
      - cluster.name=docker-cluster
      - bootstrap.memory_lock=true
      - "ES_JAVA_OPTS=-Xms512m -Xmx512m"
    ulimits:
      memlock:
        soft: -1
        hard: -1
      nofile:
        soft: 65536
        hard: 65536
    mem_limit: 1g
    cap_add:
      - IPC_LOCK
    volumes:
      - esdata1:/usr/share/elasticsearch/data
    ports:
      - 9200:9200
    networks:
      - esnet
  elasticsearch2:
    image: docker.elastic.co/elasticsearch/elasticsearch:{version}
    environment:
      - cluster.name=docker-cluster
      - bootstrap.memory_lock=true
      - "ES_JAVA_OPTS=-Xms512m -Xmx512m"
      - "discovery.zen.ping.unicast.hosts=elasticsearch1"
    ulimits:
      memlock:
        soft: -1
        hard: -1
      nofile:
        soft: 65536
        hard: 65536
    mem_limit: 1g
    cap_add:
      - IPC_LOCK
    volumes:
      - esdata2:/usr/share/elasticsearch/data
    networks:
      - esnet

volumes:
  esdata1:
    driver: local
  esdata2:
    driver: local

networks:
  esnet:
    driver: bridge
--------------------------------------------
endif::[]

To stop the cluster, type `docker-compose down`. Data volumes will persist, so it's possible to start the cluster again with the same data using `docker-compose up`.
To destroy the cluster **and the data volumes** just type `docker-compose down -v`.

===== Inspect status of cluster:

["source","sh"]
--------------------------------------------
curl -u elastic http://127.0.0.1:9200/_cat/health
Enter host password for user 'elastic':
1472225929 15:38:49 docker-cluster green 2 2 4 2 0 0 0 0 - 100.0%
--------------------------------------------
// NOTCONSOLE
// This is demonstrating curl. Console will prompt you for a username and
// password so no need to demonstrate that. Converting this would not show the
// important `-u elastic` parameters for `curl`.

Log messages go to the console and are handled by the configured Docker logging driver. By default you can access logs with `docker logs`.

[[docker-configuration-methods]]
==== Configuring Elasticsearch with Docker

Elasticsearch loads its configuration from files under `/usr/share/elasticsearch/config/`. These configuration files are documented in <<settings>> and <<jvm-options>>.

The image offers several methods for configuring Elasticsearch settings with the conventional approach being to provide customized files, i.e. `elasticsearch.yml`, but it's also possible to use environment variables to set options:

===== A. Present the parameters via Docker environment variables
For example, to define the cluster name with `docker run` you can pass `-e "cluster.name=mynewclustername"`. Double quotes are required.

===== B. Bind-mounted configuration
Create your custom config file and mount this over the image's corresponding file.
For example, bind-mounting a `custom_elasticsearch.yml` with `docker run` can be accomplished with the parameter:

["source","sh"]
--------------------------------------------
-v full_path_to/custom_elasticsearch.yml:/usr/share/elasticsearch/config/elasticsearch.yml
--------------------------------------------
IMPORTANT: The container **runs Elasticsearch as user `elasticsearch` using uid:gid `1000:1000`**. Bind mounted host directories and files, such as `custom_elasticsearch.yml` above, **need to be accessible by this user**. For the https://www.elastic.co/guide/en/elasticsearch/reference/current/important-settings.html#path-settings[data and log dirs], such as `/usr/share/elasticsearch/data`, write access is required as well.

===== C. Customized image
In some environments, it may make more sense to prepare a custom image containing your configuration. A `Dockerfile` to achieve this may be as simple as:

["source","sh",subs="attributes"]
--------------------------------------------
FROM docker.elastic.co/elasticsearch/elasticsearch:{version}
ADD elasticsearch.yml /usr/share/elasticsearch/config/
USER root
RUN chown elasticsearch:elasticsearch config/elasticsearch.yml
USER elasticsearch
--------------------------------------------

You could then build and try the image with something like:

["source","sh"]
--------------------------------------------
docker build --tag=elasticsearch-custom .
docker run -ti -v /usr/share/elasticsearch/data elasticsearch-custom
--------------------------------------------

===== D. Override the image's default https://docs.docker.com/engine/reference/run/#cmd-default-command-or-options[CMD]

Options can be passed as command-line options to the Elasticsearch process by
overriding the default command for the image. For example:

["source","sh"]
--------------------------------------------
docker run <various parameters> bin/elasticsearch -Ecluster.name=mynewclustername
--------------------------------------------

==== Notes for production use and defaults

We have collected a number of best practices for production use.

NOTE: Any Docker parameters mentioned below assume the use of `docker run`.

. Elasticsearch inside the container runs as user `elasticsearch` using uid:gid `1000:1000`. If you are bind mounting a local directory or file, ensure it is readable by this user while the https://www.elastic.co/guide/en/elasticsearch/reference/current/important-settings.html#path-settings[data and log dirs] additionally require write access.

. It is important to correctly set capabilities and ulimits via the Docker CLI. As seen earlier in the example <<docker-prod-cluster-composefile,docker-compose.yml>>, the following options are required:
+
  --cap-add=IPC_LOCK --ulimit memlock=-1:-1 --ulimit nofile=65536:65536
+
. Ensure `bootstrap.memory_lock` is set to `true` as explained in "<<setup-configuration-memory,Disable swapping>>".
+
This can be achieved through any of the <<docker-configuration-methods,configuration methods>>, e.g. by setting the appropriate environments variable with `-e "bootstrap.memory_lock=true"`.
+
. The image https://docs.docker.com/engine/reference/builder/#/expose[exposes] TCP ports 9200 and 9300. For clusters it is recommended to randomize the published ports with `--publish-all`, unless you are pinning one container per host.
+
. Use the `ES_JAVA_OPTS` environment variable to set heap size, e.g. to use 16GB use `-e ES_JAVA_OPTS="-Xms16g -Xmx16g"` with `docker run`. It is also recommended to set a https://docs.docker.com/engine/reference/run/#user-memory-constraints[memory limit] for the container.
+
. Pin your deployments to a specific version of the Elasticsearch Docker image, e.g. +docker.elastic.co/elasticsearch/elasticsearch:{version}+.
+
. Always use a volume bound on `/usr/share/elasticsearch/data`, as shown in the <<docker-cli-run-prod-mode,production example>>, for the following reasons:
+
.. The data of your elasticsearch node won't be lost if the container is killed
.. Elasticsearch is I/O sensitive and the Docker storage driver is not ideal for fast I/O
.. It allows the use of advanced https://docs.docker.com/engine/extend/plugins/#volume-plugins[Docker volume plugins]
+
. If you are using the devicemapper storage driver (default on at least RedHat (rpm) based distributions) make sure you are not using the default `loop-lvm` mode. Configure docker-engine to use https://docs.docker.com/engine/userguide/storagedriver/device-mapper-driver/#configure-docker-with-devicemapper[direct-lvm] instead.
+
. Consider centralizing your logs by using a different https://docs.docker.com/engine/admin/logging/overview/[logging driver]. Also note that the default json-file logging driver is not ideally suited for production use.


include::next-steps.asciidoc[]
