Defining a Kerberos scheme

Configure DataStax Enterprise nodes to use Kerberos authentication.

Prerequisites

Completely set up Kerberos for DSE nodes before turning on Kerberos authentication. When switching authentication methods, or enabling authentication for the first time in a production environment, DataStax recommends setting up applications to use Kerberos tickets before restricting access to only authenticated connections. When DSE Authenticator is disabled, the credentials portion of the connection request is ignored. Therefore, you can pass Kerberos tickets to DSE before implementing authentication in the environment.

Change the replication strategy and default replication factor for the system_auth and dse_security keyspaces, see Configuring system_auth keyspace replication

How to add the Kerberos authenticator to cassandra.yaml and Kerberos options to dse.yaml.

cassandra.yaml

The location of the cassandra.yaml file depends on the type of installation:
Package installations /etc/dse/cassandra/cassandra.yaml
Tarball installations installation_location/resources/cassandra/conf/cassandra.yaml

dse.yaml

The location of the dse.yaml file depends on the type of installation:
Package installations /etc/dse/dse.yaml
Tarball installations installation_location/resources/dse/conf/dse.yaml

Procedure

  1. On each node, edit the cassandra.yaml file to set the authenticator to the DSE Authenticator.
    authenticator: com.datastax.bdp.cassandra.auth.DseAuthenticator
  2. Set the native_transport_address and listen_address to the IP address. Do not use localhost or the hostname.
    native_transport_address: 100.200.182.1
    listen_address: 100.200.182.1
  3. On each node, edit the dse.yaml file:
    1. Set Kerberos as default or other scheme in the authentication options:
      authentication_options:
          enabled: false
          default_scheme: kerberos
          other_schemes:
              - internal
          scheme_permissions: true
          allow_digest_with_kerberos: true
          plain_text_without_ssl: warn
          transitional_mode: disabled
      Note: When initially enabling authentication, specify the internal scheme as the default or other. After restarting DSE, to establish roles requires using the internal default cassandra account.
      Table 1. authentication_options
      Option Description
      /en/dse/6.0/dse-admin/datastax_enterprise/config/configDseYaml.html#configDseYaml__auth_enabled Turns on authentication using the default scheme.
      default_scheme Specifies the authentication scheme when not defined in the connection:
      • internal - Plain text authentication using internal login role with password, supply the role name and password as credentials. No additional configuration required.
      • ldap - Plain text authentication using pass-through LDAP authentication. See Defining an LDAP scheme.
      • kerberos - GSSAPI authentication using the Kerberos authenticator. See Defining a Kerberos scheme.
      other_schemes other_schemes
      scheme_permissions Validate that the role mapped to user matches the authentication scheme. Grant the role permission to the scheme.
      allow_digest_with_kerberos Allow Kerberos digest-md5 authentication.
      plain_text_without_ssl Handling of plain text connection requests:
      • block - Block the request with an authentication error.
      • warn - Log a warning about the request but allow it to continue.
      • allow - Allow the request without any warning.
      transitional_mode Sets the behavior when authentication fails and credentials are missing:
      • disabled - Transitional mode is disabled. All connections must provide valid credentials and map to a login-enabled role.
      • permissive - Only super users are authenticated and logged in. All other authentication attempts are logged in as the anonymous user.
      • normal - Allow all connections that provide credentials. Maps all authenticated users to their role AND maps all other connections to anonymous.
      • strict - Allow only authenticated connections that map to a login-enabled role OR connections that provide a blank username and password as anonymous.
    2. Configure the Kerberos options.

      The options are located in the kerberos_options section.

      Example:
      kerberos_options:
         keytab: /etc/dse/dse.keytab 
         service_principal: dse/_HOST@REALM
         http_principal: HTTP/_HOST@REALM
         qop: auth
      Table 2. kerberos_options
      Option Description
      keytab The keytab file must contain the credentials for both of the fully resolved principal names, which replace _HOST with the FQDN of the host in the service_principal and http_principal settings. The UNIX user running DataStax Enterprise must also have read permissions on the keytab.
      service_principal Sets the principals name for the DSE database and DSE Search (Solr) processes. Use the form dse/_HOST@REALM, where dse is the service name.

      Leave _HOST as is. This variable is used in dse.yaml. DataStax Enterprise automatically substitutes the FQDN of the host where it runs. Credentials must exist for this principal in the keytab file and readable by the user that Cassandra runs as, usually cassandra.

      The service_principal must be consistent everywhere:
      • dse.yaml file
      • keytab
      • cqlshrc file (where it is separated into the service/hostname)
      http_principal The http_principal is used by the Tomcat application container to run DSE Search. The Tomcat web server uses the GSSAPI mechanism (SPNEGO) to negotiate the GSSAPI security mechanism (Kerberos). Set REALM to the name of your Kerberos realm. In the Kerberos principal, REALM must be uppercase.
      qop A comma-delimited list of Quality of Protection (QOP) values that clients and servers can use for each connection. The client can have multiple QOP values, while the server can have only a single QOP value. The valid values are:
      • auth - Default: Authentication only.
      • auth-int - Authentication plus integrity protection for all transmitted data.
      • auth-conf - Authentication plus integrity protection and encryption of all transmitted data.

        Encryption using auth-conf is separate and independent of whether encryption is done using SSL. If both auth-conf and SSL are enabled, the transmitted data is encrypted twice. DataStax recommends choosing only one method and using it for both encryption and authentication.

  4. When adding a Kerberos scheme to an authentication enabled cluster, configure Kerberos roles before restarting DSE, see Setting up logins and users.

What's next

When initially configuring authentication complete the set up by: