Skip to main content
Version: 22.3

Configuring Authentication

Different components of Redpanda support different authentication methods. You can configure multiple listeners with redpanda.yaml, and with each listener, you can configure the authentication_method and optionally TLS or mTLS. The guidelines put in place by your organization determine the type of authentication that you use.

See also:

Enable authentication

To enable authentication, set kafka_enable_authorization to true, and specify at least one value for the superusers property. This superuser is used to bootstrap permissions for other users in the cluster. See Cluster configuration properties.

To update the kafka_enable_authorization property, run:

rpk cluster config set kafka_enable_authorization true

To specify a superuser, run:

rpk cluster config set superusers ['admin']

To edit a superuser, use the edit command to apply the new value:

rpk cluster config edit

Create superusers

When you configure authentication, you include one or more superusers in the Redpanda configuration file. This user has ALL permissions on the cluster and grants permissions to new users. (Without a superuser, you can create other users, but you can't grant them permissions to the cluster.)

Specify the name of the superuser. This can be a new user or an existing user. For example, if you use the superuser named admin, then Redpanda allows the admin user to do anything, but Redpanda does not create the admin user. To create this superuser, run:

rpk acl user create <superuser_username> -p <superuser_password>

Now the admin user has full access to the cluster and can grant permissions to other users.

The Admin API defaults to localhost:9644. If you've configured the Admin API to use a different address/port, use the --api-urls <address:port> flag.

Creating ACLs for users uses the Kafka protocol (default of localhost:9092). Because no ACLs exist at the start, you need a superuser to bypass the requirement of needing ACLs to create ACLs.

To create users and set passwords, run:

rpk acl user create admin \
-p <password> \
--api-urls localhost:9644

For information about using rpk to manage ACL users, see rpk acl.

tip

As a security best practice, don't use the superuser to interact with the cluster, and don't delete the superuser (in case you need to grant permissions to new users later). In addition, when you create the superuser, you specify a password, which adds a level of security. If you delete the user, someone else could re-create the user with a different password.

SASL/SCRAM

Simple Authentication Security Layer (SASL) is an authentication framework that lets the user choose the authentication mechanism. Redpanda supports the Salted Challenge Response Authentication Mechanism (SCRAM) authentication method.

note

SASL authentication is only available for the Kafka API.

SASL provides authentication, but not encryption. You can, however, configure TLS to only handle encryption, and use SASL for authentication. This is useful if you require flexibility in your authorization mechanisms.

SCRAM provides strong encryption for user names and passwords by default and does not require an external data store for user information. Redpanda supports the following SASL mechanisms:

  • SCRAM-SHA-256
  • SCRAM-SHA-512

When you run a command with SASL authentication, you must include the mechanism with the following flag:

--sasl-mechanism <mechanism>

For example, to use the SCRAM-SHA-256 mechanism, run:

rpk topic create littlefoot \
--user panda \
--password pandaPassword \
--sasl-mechanism SCRAM-SHA-256

Configure SASL authentication

To configure SASL authentication for the Kafka API, set authentication_method of the listener to sasl.

In redpanda.yaml, enter:

redpanda:
kafka_api:
- address: 0.0.0.0
port: 9092
name: sasl_listener
authentication_method: sasl

Enable SASL with TLS encryption

To enable SASL authentication with TLS encryption for the Kafka API, in redpanda.yaml, enter:

redpanda:
kafka_api:
- address: 0.0.0.0
port: 9092
name: sasl_tls_listener
authentication_method: sasl
kafka_api_tls:
- name: sasl_tls_listener
key_file: server.key
cert_file: server.crt
truststore_file: ca.crt
enabled: true
require_client_auth: false

Configure Schema Registry and HTTP Proxy to connect to Redpanda with SASL

Schema Registry and HTTP Proxy connect to Redpanda over the Kafka API. For the Kafka username and password, Redpanda uses ephemeral credentials internal to the cluster. Ephemeral credentials are regular SCRAM credentials, but they're only stored in memory and are lost when a node restarts. When the Schema Registry or HTTP Proxy start up, they broadcast an ephemeral credential to other nodes over the internal RPC. If authentication fails to a particular broker, new ephemeral credentials are sent to that broker, and the service reconnects.

Manual configuration

You can override the ephemeral credentials and manually configure Schema Registry and HTTP Proxy to connect to Redpanda with SASL.

The Schema Registry configuration node is schema_registry_client:

schema_registry_client:
brokers:
- address: 127.0.0.1
port: 9092
scram_username: panda
scram_password: pandaPassword
sasl_mechanism: SCRAM-SHA-256

If TLS is in use, additional configuration is required:

schema_registry_client:
brokers:
- address: 127.0.0.1
port: 9092
broker_tls:
key_file: server.key
cert_file: server.crt
truststore_file: ca.crt
enabled: true
scram_username: panda
scram_password: pandaPassword
sasl_mechanism: SCRAM-SHA-256

HTTP Proxy has a similar configuration, but the configuration node is pandaproxy_client:

pandaproxy_client:
brokers:
- address: 127.0.0.1
port: 9092
broker_tls:
key_file: server.key
cert_file: server.crt
truststore_file: ca.crt
enabled: true
scram_username: panda
scram_password: pandaPassword
sasl_mechanism: SCRAM-SHA-256

Connect to Redpanda

You can use the newly-created user to interact with Redpanda with rpk:

rpk topic describe test-topic \
--user admin \
--password <password> \
--sasl-mechanism SCRAM-SHA-256 \
--brokers localhost:9092
SUMMARY
=======
NAME test-topic
PARTITIONS 1
REPLICAS 1

CONFIGS
=======
KEY VALUE SOURCE
cleanup.policy delete DYNAMIC_TOPIC_CONFIG
compression.type producer DEFAULT_CONFIG
message.timestamp.type CreateTime DEFAULT_CONFIG
...

Configure basic authentication

note

Basic authentication is supported on the Admin API, Schema Registry, and HTTP Proxy.

To configure basic authentication on the Admin API, set admin_api_require_auth to true. Administrators create users with rpk acl user create. This adds users to the Redpanda credential store that HTTP basic authentication uses.

You can enable basic authentication to use Kafka API username/password credentials to authenticate to HTTP Proxy and Schema Registry. This requires that SASL is turned on for Kafka API endpoints.

  • HTTP Proxy: Access to the Kafka API impersonates the user whose credentials were used to authenticate to HTTP Proxy, and the user is subject to authorization restrictions by Redpanda ACLs. To support this design, Redpanda passes the username/password in memory to a SASL-enabled Kafka client.

  • Schema Registry: Authorization is "all or nothing": if the user presents a valid user account, then they have full read/write access.

To configure basic authentication, set authentication_method to http_basic.

In redpanda.yaml, enter:

pandaproxy:
pandaproxy_api:
- address: "localhost"
port: 8082
authentication_method: http_basic

schema_registry:
schema_registry_api:
address: "localhost"
port: 8081
authentication_method: http_basic

Then to use basic authentication:

rpk acl user create foo --password bar # Creates SASL user "foo" for the Kafka API
curl -u "foo:bar" "http://localhost:8082/topics" # A request to the HTTP Proxy with user foo. Don't forget the colon!
curl -u "foo:bar" "http://localhost:8081/subjects" # A request to the Schema Registry with user foo. Don't forget the colon!

Configure mTLS with authentication

For mTLS authentication, Redpanda uses configurable rules to extract the principal from the Distinguished Name (DN) of an mTLS (X.509) certificate. It uses the principal as the identity or user name.

To enable mTLS authentication, set authentication_method to mtls_identity.

In redpanda.yaml, enter:

redpanda:
kafka_api:
- address: 0.0.0.0
port: 9092
name: mtls_listener
authentication_method: mtls_identity
kafka_api_tls:
- name: mtls_listener
key_file: mtls_server.key
cert_file: mtls_server.crt
truststore_file: mtls_ca.crt
enabled: true
require_client_auth: true

By default, Redpanda matches the entire DN. To override the default, specify kafka_mtls_principal_mapping_rules. This is a list of rules that provide a mapping from DN to principal.

Each rule has the following format: RULE:pattern/replacement/[LU]. Where:

  • pattern is a regular expression. For example, to extract the CN field: .*CN=([^,]+).*.
  • replace is used to adjust the match. For example, to use just the first match, use: $1.
  • L makes the match lowercase (optional).
  • U makes the match uppercase (optional).

For example, with the DN: CN=www.redpanda.com,O=Redpanda,OU=Engineering,L=London,S=England,C=UK

RulePrincipal
RULE:.*CN=([^,]+).*/$1/www.redpanda.com
RULE:.*O=([^,]+).*/$1/Redpanda
RULE:.*O=([^,]+).*/$1/Lredpanda
RULE:.*O=([^,]+),OU=([^,]+),.*,C=([^,]+)/$1-$2-$3/Lredpanda-engineering-uk
DEFAULTCN=www.redpanda.com,O=Redpanda,OU=Engineering,L=London,S=England,C=UK

The first rule that matches is used to extract a principal.

To update the kafka_mtls_principal_mapping_rules property, run:

rpk cluster config set kafka_mtls_principal_mapping_rules '["DEFAULT"]'

Configure Schema Registry and HTTP Proxy to connect to Redpanda with mTLS

Schema Registry and HTTP Proxy require valid client certificates to secure the connection to Redpanda. Continuing with the previous example, where the certificate contains an identity for authentication (kafka_api listener set to mtls_identity), the following example shows how to connect Schema Registry and HTTP Proxy to Redpanda with mTLS certificate-based identity.

In redpanda.yaml, enter:

schema_registry_client:
brokers:
- address: 127.0.0.1
port: 9092
broker_tls:
key_file: schema_registry.key
cert_file: schema_registry.crt
truststore_file: ca.crt
enabled: true
pandaproxy_client:
brokers:
- address: 127.0.0.1
port: 9092
broker_tls:
key_file: pandaproxy.key
cert_file: pandaproxy.crt
truststore_file: ca.crt
enabled: true

Disable authentication

To disable authentication for a listener, set authentication_method to none:

pandaproxy:
pandaproxy_api:
- address: "localhost"
port: 8082
authentication_method: none

schema_registry:
schema_registry_api:
address: "localhost"
port: 8081
authentication_method: none

If authorization is enabled, connections to this listener use the anonymous user.

To disable authentication on the Kafka API, disable kafka_enable_authorization and set authentication_method to none for all listeners.

For example, run rpk cluster config set kafka_enable_authorization false, and set the following:

redpanda:
kafka_api:
- address: 0.0.0.0
port: 9092
name: sasl_listener
authentication_method: none