[role="xpack"]
[[tls-http]]
==== Encrypting HTTP client communications

When {security-features} are enabled, you can optionally use TLS to ensure that
communication between HTTP clients and the cluster is encrypted.

NOTE: Enabling TLS on the HTTP layer is strongly recommended but is not required.
If you enable TLS on the HTTP layer in {es}, then you might need to make
configuration changes in other parts of the {stack} and in any {es} clients that
you use.

. If you have not done so already, <<node-certificates,generate node certificates>>.
+
--
In particular, you need the files that are generated by the following command:

[source,shell]
----------------------------------------------------------
bin/elasticsearch-certutil http
----------------------------------------------------------

This command generates a zip file that contains certificates and keys for use in
{es} and {kib}. Each folder contains a readme that explains how to use the files.
--

. Verify that you've copied the output files to the appropriate locations, as
specified in the readme files. 
+
--
For example, copy the `http.p12` file from the `elasticsearch` folder into a 
directory within the {es} configuration directory on each node. If you chose to 
generate one certificate per node, copy the appropriate `http.p12` file to each
node. If you want to use {kib} to access this cluster, copy the
`elasticsearch-ca.pem` file from the `kibana` folder into the {kib}
configuration directory.
--

. Enable TLS and specify the information required to access the node’s
certificate. For example:

.. Update the `elasticsearch.yml` file on each node with the location of the
certificates.
+
--
If the certificates are in PKCS#12 format:

[source, yaml]
--------------------------------------------------
xpack.security.http.ssl.enabled: true
xpack.security.http.ssl.keystore.path: "http.p12"
--------------------------------------------------

If you have certificates in PEM format:

[source, yaml]
--------------------------------------------------
xpack.security.http.ssl.enabled: true
xpack.security.http.ssl.key:  /home/es/config/node1_http.key <1>
xpack.security.http.ssl.certificate: /home/es/config/node1_http.crt <2>
xpack.security.http.ssl.certificate_authorities: [ "/home/es/config/ca.crt" ] <3>
--------------------------------------------------
<1> The full path to the node key file. This must be a location within the
    {es} configuration directory.
<2> The full path to the node certificate. This must be a location within the
    {es} configuration directory.
<3> An array of paths to the CA certificates that should be trusted. These paths
    must be a location within the {es} configuration directory.
--

.. If you secured the keystore or the private key with a password, add that password to a secure 
setting in {es}.
+
--
If the certificates are in PKCS#12 format:

[source,shell]
-----------------------------------------------------------
bin/elasticsearch-keystore add xpack.security.http.ssl.keystore.secure_password
-----------------------------------------------------------

If the certificates are in PEM format:

[source,shell]
-----------------------------------------------------------
bin/elasticsearch-keystore add xpack.security.http.ssl.secure_key_passphrase
-----------------------------------------------------------
--

. Optional: If you want to use {kib}, follow the instructions in the readme
provided by the `elasticsearch-certutil http` command or see
{kibana-ref}/configuring-tls.html[Encrypting communications in {kib}].

. Restart {es}.

[NOTE]
===============================
* All TLS-related node settings are considered to be highly sensitive and
therefore are not exposed via the
{ref}/cluster-nodes-info.html#cluster-nodes-info[nodes info API] For more
information about any of these settings, see <<security-settings>>.

* {es} monitors all files such as certificates, keys, keystores, or truststores 
that are configured as values of TLS-related node settings. If you update any of 
these files (for example, when your hostnames change or your certificates are 
due to expire), {es} reloads them. The files are polled for changes at 
a frequency determined by the global {es} `resource.reload.interval.high` 
setting, which defaults to 5 seconds.
===============================
