Article

Securely connect Red Hat Integration Service Registry with Red Hat AMQ Streams

April 7, 2021
Security Java Kubernetes Event-Driven
Roman Martin Gil
Roman Martin Gil
Principal Middleware Architect
Apicurio Apicurio

Red Hat Integration Service Registry is a datastore based on the Apicurio open source project. In my previous article, I showed you how to integrate Spring Boot with Service Registry. In this article, you'll learn how to connect Service Registry to a secure Red Hat AMQ Streams cluster.

Connecting Service Registry with AMQ Streams

Service Registry includes a set of pluggable storage options for storing APIs, rules, and validations. The Kafka-based storage option, provided by Red Hat AMQ Streams, is suitable for production environments where persistent storage is configured for a Kafka cluster running on Red Hat OpenShift.

Security is not optional in a production environment, and AMQ Streams must provide it for each component you connect to. Security is defined by authentication, which ensures a secure client connection to the Kafka cluster, and authorization, specifying which users can access which resources. I will show you how to set up authentication and authorization with AMQ Streams and Service Registry.

The AMQ Streams Operators

AMQ Streams and Service Registry provide a set of OpenShift Operators available from the OpenShift OperatorHub. Developers use these Operators to package, deploy, and manage OpenShift application components.

The AMQ Streams Operators provide a set of custom resource definitions (CRDs) to describe the components of a Kafka deployment. These objects—namely, Zookeeper, Brokers, Users, and Connect—provide the API that we use to manage our Kafka cluster. AMQ Streams Operators manage authentication, authorization, and the user's life cycle.

The AMQ Streams Cluster Operator manages the Kafka schema reference resource, which declares the Kafka topology and features to use.

The AMQ Streams User Operator manages the KafkaUser schema reference resource. This resource declares a user for an instance of AMQ Streams, including the user's authentication, authorization, and quota definitions.

The Service Registry Operator

The Service Registry Operator provides a set of CRDs to describe service registry deployment components such as storage, security, and replicas. Together, these objects provide the API to manage a Service Registry instance.

The Service Registry Operator uses the ApicurioRegistry schema reference to manage the service registry life cycle. The ApicurioRegistry declares the service registry topology and main features. The Apicurio Operator manages the ApicurioRegistry object.

Authentication with AMQ Streams

Red Hat AMQ Streams supports the following authentication mechanisms:

  • SASL SCRAM-SHA-512
  • Transport Layer Security (TLS) client authentication
  • OAuth 2.0 token-based authentication

These mechanisms are declared in the authentication block in each listener's Kafka definition. Each listener implements the authentication mechanism defined, so the client applications must authenticate with the mechanism identified.

Two ways to authenticate an AMQ Streams cluster

First off, let's see how to activate each mechanism in the AMQ Streams cluster. We need to identify in Service Registry the authentication mechanism activated in the AMQ Streams cluster. Service Registry only allows SCRAM-SHA-512 and TLS as authentication mechanisms. I'll show you how to configure authentication using each of these mechanisms.

Authenticating a Kafka cluster with SCRAM-SHA-512

The following Kafka definition declares a Kafka cluster secured with SCRAM-SHA-512 authentication for the secured listener (secured using the TLS protocol): 

apiVersion: kafka.strimzi.io/v1beta1
kind: Kafka
metadata:
 name: my-kafka
spec:
 kafka:
   listeners:
     tls:
       authentication:
         type: scram-sha-512

Applying this configuration creates a set of secrets where the TLS certificates are stored. The secret we need to know to allow the secured connections is declared as my-kafka-cluster-ca-cert. Note that we will need this value later on.

The following KafkaUser definition declares a Kafka user with SCRAM-SHA-512 authentication: 

apiVersion: kafka.strimzi.io/v1beta1
kind: KafkaUser
metadata:
 name: service-registry-scram
 labels:
   strimzi.io/cluster: my-kafka
spec:
 authentication:
   type: scram-sha-512

Applying this configuration creates a secret (the user's name) and stores it where the user credentials are stored. This secret contains the generated password to authenticate to the Kafka cluster: 

$ oc get secrets
NAME                    TYPE      DATA   AGE
service-registry-scram  Opaque    1      4s

Authenticating a Kafka cluster with TLS

The following Kafka definition declares a Kafka cluster secured with TLS authentication for the secured listener (secured with the TLS protocol): 

apiVersion: kafka.strimzi.io/v1beta1
kind: Kafka
metadata:
 name: my-kafka
spec:
 kafka:
   listeners:
     tls:
       authentication:
         type: tls

Applying this configuration creates a set of secrets where the TLS certificates are stored. The secret we need to know to allow the secured connections is declared as my-kafka-cluster-ca-cert. Note that we will need this value later on.

The following KafkaUser definition declares a Kafka user with TLS authentication: 

apiVersion: kafka.strimzi.io/v1beta1
kind: KafkaUser
metadata:
 name: service-registry-tls
 labels:
   strimzi.io/cluster: my-kafka
spec:
 authentication:
   type: tls

Applying this configuration creates a secret (the user's name) and stores it where the user credentials are stored. This secret contains the valid client certificates to authenticate to the Kafka cluster: 

$ oc get secrets
NAME                    TYPE      DATA   AGE
Service-registry-tls    Opaque    1      4s

Service Registry authentication

To identify the authentication mechanism activated in the AMQ Streams cluster, we need to deploy the Service Registry accordingly, using the ApicurioRegistry definition: 

apiVersion: apicur.io/v1alpha1
kind: ApicurioRegistry
metadata:
  name: service-registry
spec:
  configuration:
    persistence: "streams"
    streams:
      bootstrapServers: "my-kafka-kafka-bootstrap:9093"

Note: At the time of this writing, Service Registry can only connect to the AMQ Streams TLS listener (normally in port 9093) when the authentication mechanism is activated in that listener. The ApicurioRegistry definition's boostrapServers property must point to that listener port.

Service Registry authentication using SCRAM-SHA-512

The following ApicurioRegistry definition declares a secured connection with a user with SCRAM-SHA-512 authentication: 

apiVersion: apicur.io/v1alpha1
kind: ApicurioRegistry
metadata:
  name: service-registry
spec:
  configuration:
    persistence: "streams"
    streams:
      bootstrapServers: "my-kafka-kafka-bootstrap:9093"
      security:
        scram:
          user: service-registry-scram
          passwordSecretName: service-registry-scram
          truststoreSecretName: my-kafka-cluster-ca-cert

We need to identify the following values in this object:

  • User: The username to be securely connected.
  • PasswordSecretName:  The name of the secret where the password is saved.
  • TruststoreSecretName: The name of secret with the certificate authority (CA) certificates for the deployed Kafka cluster.

Service Registry authentication using TLS

The following ApicurioRegistry definition declares a secured connection with a user with a TLS authentication: 

apiVersion: apicur.io/v1alpha1
kind: ApicurioRegistry
metadata:
  name: service-registry
spec:
  configuration:
    persistence: "streams"
    streams:
      bootstrapServers: "my-kafka-kafka-bootstrap:9093"
      security:
        tls:
          keystoreSecretName: service-registry-tls
          truststoreSecretName: my-kafka-cluster-ca-cert

The values that we need to identify in this object are:

  • KeystoreSecretName: The name of the user secret with the client certificates.
  • TruststoreSecretName: The name of the secret with the CA certificates for the deployed Kafka cluster.

Authorization with AMQ Streams

AMQ Streams supports authorization using SimpleACLAuthorizer globally for all listeners used for client connections. This mechanism uses access control lists (ACLs) to define which users have access to which resources.

Denial is the default access control if authorization is applied in the Kafka cluster. The listener must declare different rules for each user that wishes to operate within the Kafka cluster.

The Kafka definition

The following Kafka definition activates authorization in the Kafka cluster: 

apiVersion: kafka.strimzi.io/v1beta1
kind: Kafka
metadata:
 name: my-kafka
spec:
 kafka:
   authorization:
     type: simple

The KafkaUser definition

An ACL is declared for each user in the KafkaUser definition. The acls section (see below) includes a list of resources, where each resource is declared as a new rule:

  • Resource type: Identifies the type of object managed in Kafka; objects include topics, consumer groups, clusters, transaction IDs, and delegation tokens.
  • Resource name: Identifies the resource where the rule is applied. The resource name could be defined as a literal, to identify one resource, or as a prefix pattern, to identify a list of resources.
  • Operation: Declares the kind of operations allowed. A full list of operations available for each resource type is available here.

For a Service Registry user to work successfully with our secured AMQ Streams cluster, we must declare the following rules specifying what the user is allowed to do:

  • Read its own consumer group.
  • Create, read, write, and describe on a global ID topic (global-id-topic).
  • Create, read, write, and describe on a storage topic (storage-topic).
  • Create, read, write, and describe on its own local changelog topics.
  • Describe and write transactional IDs on its own local group.
  • Read on a consumer offset topic (__consumer_offsets).
  • Read on a transaction state topic (__transaction_state).
  • Write idempotently on a cluster.

The ACL definition

Here is an example ACL definition: 

    acls:
      # Group Id to consume information for the different topics used by the Service Registry.
      # Name equals to metadata.name property in ApicurioRegistry object
      - resource:
          type: group
          name: service-registry
        operation: Read
      # Rules for the Global global-id-topic
      - resource:
          type: topic
          name: global-id-topic
        operation: Read
      - resource:
          type: topic
          name: global-id-topic
        operation: Describe
      - resource:
          type: topic
          name: global-id-topic
        operation: Write
      - resource:
          type: topic
          name: global-id-topic
        operation: Create
      # Rules for the Global storage-topic
      - resource:
          type: topic
          name: storage-topic
        operation: Read
      - resource:
          type: topic
          name: storage-topic
        operation: Describe
      - resource:
          type: topic
          name: storage-topic
        operation: Write
      - resource:
          type: topic
          name: storage-topic
        operation: Create
      # Rules for the local topics created by our Service Registry instance
      # Prefix value equals to metadata.name property in ApicurioRegistry object
      - resource:
          type: topic
          name: service-registry-
          patternType: prefix
        operation: Read
      - resource:
          type: topic
          name: service-registry-
          patternType: prefix
        operation: Describe
      - resource:
          type: topic
          name: service-registry-
          patternType: prefix
        operation: Write
      - resource:
          type: topic
          name: service-registry-
          patternType: prefix
        operation: Create
      # Rules for the local transactionalsIds created by our Service Registry instance
      # Prefix equals to metadata.name property in ApicurioRegistry object
      - resource:
          type: transactionalId
          name: service-registry-
          patternType: prefix
        operation: Describe
      - resource:
          type: transactionalId
          name: service-registry-
          patternType: prefix
        operation: Write
      # Rules for internal Apache Kafka topics
      - resource:
          type: topic
          name: __consumer_offsets
        operation: Read
      - resource:
          type: topic
          name: __transaction_state
        operation: Read
      # Rules for Cluster objects
      - resource:
          type: cluster
        operation: IdempotentWrite

Note that activating authorization in AMQ Streams does not affect the ApicurioRegistry definition. It is only related to the correct ACL definitions in the KafkaUser objects.

Summary

Connecting Service Registry's security capabilities to secure AMQ Streams clusters enables your production environment to prompt a warning about your security requirements. This article introduced the Service Registry and AMQ Streams components concerned with security requirements and showed you how to apply them successfully.

For a deeper understanding and analysis, please refer to the following references:

Last updated: April 5, 2021

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