[[installing-shield]]
== Installing Shield

The <<getting-started, Getting Started Guide>> steps through a basic Shield installation. This section provides some additional information about the installation prerequisites, deployment options, and the installation process for RPM/DEB package installations.

IMPORTANT: The Shield plugin must be installed on every node in the cluster and every
node must be restarted after installation. Plan for a complete cluster restart before beginning the installation process.

[float]
=== Shield Installation Prerequisites

To install Shield 2.x, you need:

* Java 7 or later
* Elasticsearch 2.x
* Elasticsearch License plugin 2.x

For information about installing the latest Oracle JDK, see http://www.oracle.com/technetwork/java/javase/downloads/index-jsp-138363.html[Java SE Downloads]. For information about installing Elasticsearch, see http://www.elastic.co/guide/en/elasticsearch/reference/current/_installation.html[Installation] in the Elasticsearch Reference.

[float]
[[deb-rpm-install]]
=== Installing Shield on a DEB/RPM Package Installation

If you install Elasticsearch as a package or you specify a custom configuration directory, the command line
tools require you to specify the configuration directory. On Linux systems, add the following line to your
`.profile` file:

[source,shell]
----------------------------------------------------------
export ES_JAVA_OPTS="-Des.path.conf=/etc/elasticsearch"
----------------------------------------------------------

NOTE: When using `sudo` to run commands as a different user, the `ES_JAVA_OPTS` setting from your profile will not be
available in the other user's environment. You can manually pass the environment variables to the command or you can
make the environment variable available by adding the following line to the `/etc/sudoers` file:

[source,shell]
----------------------------------------------------------
Defaults    env_keep += "ES_JAVA_OPTS"
----------------------------------------------------------

On Windows systems, the `setx` command can be used to specify a custom configuration directory:

[source,shell]
----------------------------------------------------------
setx ES_JAVA_OPTS "-Des.path.conf=C:\config"
----------------------------------------------------------


If your server doesn't have direct Internet access, see <<offline-install,Installing Shield on Offline Machines>> for information about downloading the Shield binaries.

[float]
[[offline-install]]
=== Installing Shield on Offline Machines

Elasticsearch’s `bin/plugin` script requires direct Internet access for downloading and installing the security plugin.
If your server doesn’t have Internet access, you can download the required binaries from the following link:

[source,sh]
----------------------------------------------------
https://download.elastic.co/elasticsearch/shield/shield-1.3.0.zip
----------------------------------------------------

Transfer the compressed file to your server, then install the plugin with the `bin/plugin` script:

[source,shell]
----------------------------------------------------
bin/plugin install shield -u file://PATH_TO_ZIP_FILE <1>
----------------------------------------------------
<1> Absolute path to Shield plugin zip distribution file (e.g. `file:///path/to/file/shield-1.3.0.zip`,
    note the three slashes at the beginning)

[float]
[[tribe-node]]
=== Installing Shield on Tribe Nodes

Shield supports the {ref}/modules-tribe.html[Tribe Node], which acts as a federated client across multiple clusters. When using Tribe Nodes with Shield, you must have the same Shield configuration (users, roles, user-role mappings, SSL/TLS CA) on each cluster, and on the Tribe Node itself, where security checking is primarily done. This, of course, also means
that all clusters must be running Shield. 

To use a Tribe Node with Shield:

. Configure the same privileges on all connected clusters. The Tribe Node has its own configuration and privileges, which need to grant access to actions and indices on all of the
connected clusters. Also, each cluster needs to grant access to indices belonging to other connected clusters as well.
+
Let's look at an example: assuming we have two clusters, `cluster1` and `cluster2`, each one holding an index, `index1`
and `index2`. A search request that targets multiple clusters, as follows
+
[source,shell]
-----------------------------------------------------------
curl -XGET tribe_node:9200/index1,index2/_search -u tribe_user:tribe_user
-----------------------------------------------------------
+
requires `search` privileges for both `index1` and `index2` on the Tribe Node:
+
[source,yaml]
-----------------------------------------------------------
tribe_user:
  indices:
    'index*': search
-----------------------------------------------------------
+
Also, the same privileges need to be granted on the connected clusters, meaning that `cluster1` has to grant access to
`index2` even though `index2` only exists on `cluster2`; the same requirement applies for `index1` on `cluster2`. This
applies to any indices action. As for cluster state read operations (e.g. cluster state api, get mapping api etc.),
they always get executed locally on the Tribe Node, to make sure that the merged cluster state gets returned; their
privileges are then required on the Tribe Node only.

. Use the same system key on all clusters. For <<enable-message-authentication,message authentication>> to properly work across multiple clusters, the Tribe Node
and all of the connected clusters need to share the same system key.

. Enable encryption globally. Encrypted communication via SSL/TLS can only be enabled globally, meaning that either all of the connected clusters and the Tribe Node have SSL enabled, or none of them have.

. Use the same certification authority on all clusters. When using encrypted communication, for simplicity, we recommend all of the connected clusters and the Tribe Node use
the same certification authority to generate their certificates.

[float]
==== Tribe Node Example

Let's see a complete example on how to use the Tribe Node with shield and the configuration required. First of all the
Shield and License plugins need to be installed and enabled on all clusters and on the Tribe Node.

The system key needs to be generated on one node, as described in <<enable-message-authentication, Enabling Message Authentication>>,
and then copied over to all of the other nodes in each cluster and the Tribe Node itself.

Each cluster can have its own users with `admin` privileges that don't need to be present in the Tribe Node too. In fact,
administration tasks (e.g. create index) cannot be performed through the Tribe Node but need to be sent directly to the
corresponding cluster. The users that need to be created on Tribe Node are those that allow to get back data merged from
the different clusters through the Tribe Node itself. Let's for instance create as follows a `tribe_user` user, with
role `user`, that has `read` privileges on any index.

[source,shell]
-----------------------------------------------------------
./bin/shield/esusers useradd tribe_user -p tribe_user -r user
-----------------------------------------------------------

The above command needs to be executed on each cluster, since the same user needs to be present on the Tribe Node as well
as on every connected cluster.

The following is the configuration required on the Tribe Node, that needs to be added to `elasticsearch.yml`.
Elasticsearch allows to list specific settings per cluster. We disable multicast discovery as described in the
<<disable-multicast, Disable Multicast section>> and configure the proper unicast discovery hosts for each cluster,
as well as their cluster names:

[source,yaml]
-----------------------------------------------------------
tribe:
  t1:
    cluster.name: tribe1
    discovery.zen.ping.multicast.enabled: false
    discovery.zen.ping.unicast.hosts: ["tribe1:9300"]
  t2:
    cluster.name: tribe2
    discovery.zen.ping.multicast.enabled: false
    discovery.zen.ping.unicast.hosts: ["tribe2:9300"]
-----------------------------------------------------------

The Tribe Node can then be started and once initialized it will be ready to accept requests like the following search,
which will return documents coming from the different connected clusters:

[source,shell]
-----------------------------------------------------------
curl -XGET localhost:9200/_search -u tribe_user:tribe_user
-----------------------------------------------------------

As for encrypted communication, the required settings are the same as described in <<securing-communications, Securing Communications with Encryption and IP Filtering>>,
but need to be specified per tribe as we did for discovery settings above.





