Security

Elasticsearch SQL integrates with security, if this is enabled on your cluster. In such a scenario, Elasticsearch SQL supports both security at the transport layer (by encrypting the communication between the consumer and the server) and authentication (for the access layer).

SSL/TLS configuration

In case of an encrypted transport, the SSL/TLS support needs to be enabled in Elasticsearch SQL to properly establish communication with Elasticsearch. This is done by setting the ssl property to true or by using the https prefix in the URL.
Depending on your SSL configuration (whether the certificates are signed by a CA or not, whether they are global at JVM level or just local to one application), might require setting up the keystore and/or truststore, that is where the credentials are stored (keystore - which typically stores private keys and certificates) and how to verify them (truststore - which typically stores certificates from third party also known as CA - certificate authorities).
Typically (and again, do note that your environment might differ significantly), if the SSL setup for Elasticsearch SQL is not already done at the JVM level, one needs to setup the keystore if the Elasticsearch SQL security requires client authentication (PKI - Public Key Infrastructure), and setup truststore if SSL is enabled.

Authentication

The authentication support in Elasticsearch SQL is of two types:

Username/Password

Set these through user and password properties.

PKI/X.509

Use X.509 certificates to authenticate Elasticsearch SQL to Elasticsearch. For this, one would need to setup the keystore containing the private key and certificate to the appropriate user (configured in Elasticsearch) and the truststore with the CA certificate used to sign the SSL/TLS certificates in the Elasticsearch cluster. That is, one should setup the key to authenticate Elasticsearch SQL and also to verify that is the right one. To do so, one should set the ssl.keystore.location and ssl.truststore.location properties to indicate the keystore and truststore to use. It is recommended to have these secured through a password in which case ssl.keystore.pass and ssl.truststore.pass properties are required.

Permissions (server-side)

Lastly, one the server one need to add a few permissions to users so they can run SQL. To run SQL a user needs read and indices:admin/get permissions at minimum while some parts of the API require cluster:monitor/main.

The following example configures a role that can run SQL in JDBC querying the test and bort indices:

cli_or_drivers_minimal:
  cluster:
    - "cluster:monitor/main"
  indices:
    - names: test
      privileges: [read, "indices:admin/get"]
    - names: bort
      privileges: [read, "indices:admin/get"]