[role="xpack"]
[testenv="basic"]
[[encrypting-internode-communications]]
== Tutorial: Encrypting communications

In the {stack-gs}/get-started-elastic-stack.html[Getting started with the {stack}]
and <<security-getting-started,Getting started with security>> tutorials, we
used a cluster with a single {es} node to get up and running with the {stack}.

You can add as many nodes as you want in a cluster but they must be able to
communicate with each other. The communication between nodes in a cluster is
handled by the {ref}/modules-transport.html[transport module]. To secure your
cluster, you must ensure that the internode communications are encrypted.

NOTE: In this tutorial, we add more nodes by installing more copies of {es} on
the same machine. By default, {es} binds to loopback addresses for HTTP and
transport communication. That is fine for the purposes of this tutorial and for
downloading and experimenting with {es} in a test or development environment.
When you are deploying a production environment, however, you are generally
adding nodes on different machines so that your cluster is resilient to outages
and avoids data loss. In a production scenario, there are additional
requirements that are not covered in this tutorial. See
{ref}/bootstrap-checks.html#dev-vs-prod-mode[Development vs production mode] and
{ref}/add-elasticsearch-nodes.html[Adding nodes to your cluster].

[float]
[[encrypting-internode-prerequisites]]
=== Before you begin

Ideally, you should do this tutorial after you complete the 
{stack-gs}/get-started-elastic-stack.html[Getting started with the {stack}] and
<<security-getting-started,Getting started with security>> tutorials.

At a minimum, you must install and configure {es} and {kib} in a cluster with a
single {es} node. In particular, this tutorial provides instructions for adding
nodes that work with the `zip` and `tar.gz` packages.

IMPORTANT: To complete this tutorial, you must install the default {es} and
{kib} packages, which include the encrypted communications {security-features}.
When you install these products, they apply basic licenses with no expiration
dates. All of the subsequent steps in this tutorial assume that you are using a
basic license. For more information, see {subscriptions} and
{kibana-ref}/managing-licenses.html[License management].

include::tutorial-tls-certificates.asciidoc[]
include::tutorial-tls-internode.asciidoc[]
include::tutorial-tls-addnodes.asciidoc[]