Add documentation for setting the OpenSearch keystore password (#6795)

* Add documentation for setting the OpenSearch keystore password

Signed-off-by: Craig Perkins <[email protected]>

* Verb tense

Signed-off-by: Craig Perkins <[email protected]>

* Update opensearch-keystore.md

* Apply suggestions from code review

Signed-off-by: Naarcha-AWS <[email protected]>

---------

Signed-off-by: Craig Perkins <[email protected]>
Signed-off-by: Naarcha-AWS <[email protected]>
Co-authored-by: Naarcha-AWS <[email protected]>

_security/configuration/opensearch-keystore.md

@@ -48,34 +48,52 @@ The following examples provide the basic syntax for common `opensearch-keystore`
 
 ### Creating a new keystore
 
-**Command**
+The following command creates a new keystore:
 
 ```bash
 ./bin/opensearch-keystore create
 ```
 {% include copy.html %}
 
 If a keystore already exists, the script will ask whether you would like to overwrite the existing keystore.
-
-**Response**
 
 The script responds with a confirmation that the keystore was created:
 
 ```bash
 Created opensearch keystore in $OPENSEARCH_HOME/config/opensearch.keystore
 ```
 
+### Setting a keystore password
+
+The following command sets a new keystore password:
+
+```bash
+./bin/opensearch-keystore passwd
+```
+{% include copy.html %}
+
+If a keystore password already exists, the script will ask for the current keystore password before you can reset the password.
+
+**Response**
+
+The script responds with a confirmation that the keystore password was set successfully:
+
+```bash
+OpenSearch keystore password changed successfully.
+```
+
+When starting OpenSearch you will be prompted to enter the keystore password. Alternatively, you can set the environment variable KEYSTORE_PASSWORD to avoid being prompted for password on startup.
+{: .note}
+
 ### Listing settings in the keystore
 
-**Command**
+The following commands list all setting currently in the keystore:
 
 ```bash
 ./bin/opensearch-keystore list
 ```
 {% include copy.html %}
 
-**Response**
-
 The script responds with a list of settings in the keystore:
 
 ```bash
@@ -85,26 +103,24 @@ plugins.security.ssl.http.pemkey_password_secure
 
 ### Adding a new setting
 
+The following command adds a new keystore setting:
+
 ```bash
 ./bin/opensearch-keystore add plugins.security.ssl.http.pemkey_password_secure
 ```
 {% include copy.html %}
 
-**Response**
-
 After this command, you will be prompted to enter the secret key securely.
 
 ### Removing a setting
 
-**Command**
+The following command removes a keystore setting:
 
 ```bash
 ./bin/opensearch-keystore remove plugins.security.ssl.http.pemkey_password_secure
 ```
 {% include copy.html %}
 
-**Response**
-
 No response exists for this command. To confirm that the setting was deleted, use `opensearch-keystore list`.
 
 ## KeyStore entries as OpenSearch settings