bitnamicharts/schema-registry repository overview

⁠Bitnami Secure Images Helm chart for Confluent Schema Registry

Confluent Schema Registry provides a RESTful interface by adding a serving layer for your metadata on top of Kafka. It expands Kafka enabling support for Apache Avro, JSON, and Protobuf schemas.

Overview of Confluent Schema Registry⁠

Trademarks: This software listing is packaged by Bitnami. The respective trademarks mentioned in the offering are owned by the respective companies, and use of them does not imply any affiliation or endorsement.

⁠ TL;DR

helm install my-release oci://REGISTRY_NAME/REPOSITORY_NAME/schema-registry

⁠ Introduction

This chart bootstraps a Schema Registry⁠ statefulset on a Kubernetes⁠ cluster using the Helm⁠ package manager.

⁠ Before you begin

• Kubernetes 1.23+
• Helm 3.8.0+
• PV provisioner support in the underlying infrastructure

⁠ Installing the chart

To install the chart with the release name my-release:

helm install my-release oci://REGISTRY_NAME/REPOSITORY_NAME/schema-registry

These commands deploy Schema Registry on the Kubernetes cluster with the default configuration. The Parameters⁠ section lists the parameters that can be configured during installation.

⁠ Configuration and installation details

This section describes resource settings, rolling tags, Kafka authentication, TLS, and other options.

⁠ Resource requests and limits

Bitnami charts allow setting resource requests and limits for all containers inside the chart deployment. These are inside the resources value (check parameter table). Setting requests is essential for production workloads and these should be adapted to your specific use case.

To make this process easier, the chart contains the resourcesPreset values, which automatically sets the resources section according to different presets. Check these presets in the bitnami/common chart⁠. However, in production workloads using resourcesPreset is discouraged as it may not fully adapt to your specific needs. Find more information on container resource management in the official Kubernetes documentation⁠.

⁠ Rolling vs immutable tags⁠

It is strongly recommended to use immutable tags in a production environment. This ensures your deployment does not change automatically if the same tag is updated with a different image.

Bitnami will release a new chart updating its containers if a new version of the main container, significant changes, or critical vulnerabilities exist.

⁠ Enable authentication for Kafka

You can configure different authentication protocols for each listener you configure in Kafka. For instance, you can use SASL over TLS authentication for client communications, while using tls for inter-broker communications. This table shows the available protocols and the security they provide:

Configure the authentication protocols for client and inter-broker communications by setting the auth.clientProtocol and auth.interBrokerProtocol parameters to the desired ones, respectively.

If you enabled SASL authentication on any listener, you can set the SASL credentials using the parameters below:

• kafka.auth.sasl.jaas.clientUsers/kafka.auth.sasl.jaas.clientPasswords: when enabling SASL authentication for communications with clients.
• kafka.auth.sasl.jaas.interBrokerUser/kafka.auth.sasl.jaas.interBrokerPassword: when enabling SASL authentication for inter-broker communications.
• kafka.auth.jaas.zookeeperUser/kafka.auth.jaas.zookeeperPassword: In the case that the Zookeeper chart is deployed with SASL authentication enabled.

For instance, you can deploy the chart with the following parameters:

kafka.auth.clientProtocol=sasl
kafka.auth.jaas.clientUsers[0]=clientUser
kafka.auth.jaas.clientPasswords[0]=clientPassword

⁠ Securing traffic using TLS

In order to configure TLS authentication/encryption, you can create a secret per Kafka broker you have in the cluster containing the Java Key Stores (JKS) files: the truststore (kafka.truststore.jks) and the keystore (kafka.keystore.jks). Then, you need pass the secret names with the kafka.auth.tls.existingSecrets parameter when deploying the chart.

For instance, to configure TLS authentication on a cluster with 2 Kafka brokers, and 1 Schema Registry replica use the commands below to create the secrets:

kubectl create secret generic schema-registry-jks --from-file=/schema-registry.truststore.jks --from-file=./schema-registry-0.keystore.jks
kubectl create secret generic kafka-jks-0 --from-file=kafka.truststore.jks=./kafka.truststore.jks --from-file=kafka.keystore.jks=./kafka-0.keystore.jks
kubectl create secret generic kafka-jks-1 --from-file=kafka.truststore.jks=./kafka.truststore.jks --from-file=kafka.keystore.jks=./kafka-1.keystore.jks

Then, deploy the chart with the following parameters:

auth.kafka.jksSecret=schema-registry-jks
auth.kafka.keystorePassword=some-password
auth.kafka.truststorePassword=some-password
kafka.replicaCount=2
kafka.auth.clientProtocol=tls
kafka.auth.tls.existingSecrets[0]=kafka-jks-0
kafka.auth.tls.existingSecrets[1]=kafka-jks-1
kafka.auth.tls.password=jksPassword

In case you want to ignore hostname verification on Kafka certificates, set the parameter auth.kafka.tls.endpointIdentificationAlgorithm with an empty string "". In this case, you can reuse the same truststore and keystore for every Kafka broker and Schema Registry replica. For instance, to configure TLS authentication on a cluster with 2 Kafka brokers, and 1 Schema Registry replica use the commands below to create the secrets:

kubectl create secret generic schema-registry-jks --from-file=schema-registry.truststore.jks=common.truststore.jks --from-file=schema-registry-0.keystore.jks=common.keystore.jks
kubectl create secret generic kafka-jks --from-file=kafka.truststore.jks=common.truststore.jks --from-file=kafka.keystore.jks=common.keystore.jks

⁠ FIPS parameters

The FIPS parameters only have effect if you are using images from the Bitnami Secure Images catalog⁠.

For more information on this new support, please refer to the FIPS Compliance section⁠.

⁠ Backup and restore

To back up and restore Helm chart deployments on Kubernetes, you need to back up the persistent volumes from the source deployment and attach them to a new deployment using Velero⁠, a Kubernetes backup/restore tool. Find the instructions for using Velero in this guide⁠.

⁠ Adding extra flags

In case you want to add extra environment variables to Schema Registry, you can use extraEnvs parameter. For instance:

extraEnvVars:
  - name: FOO
    value: BAR

⁠ Using custom configuration

This helm chart supports using custom configuration for Schema Registry.

You can specify the configuration for Schema Registry using the configuration parameter. In addition, you can also set an external configmap with the configuration file. This is done by setting the existingConfigmap parameter.

⁠ Sidecars and Init Containers

If you have a need for additional containers to run within the same pod as Schema Registry (e.g. an additional metrics or logging exporter), you can do so using the sidecars config parameter. Simply define your container according to the Kubernetes container spec.

sidecars:
  - name: your-image-name
    image: your-image
    imagePullPolicy: Always
    ports:
      - name: portname
       containerPort: 1234

Similarly, you can add extra init containers using the initContainers parameter.

initContainers:
  - name: your-image-name
    image: your-image
    imagePullPolicy: Always
    ports:
      - name: portname
        containerPort: 1234

⁠ Using an external Kafka

Sometimes you may want to have Schema Registry connect to an external Kafka cluster rather than installing one as dependency. To do this, the chart allows you to specify credentials for an existing Kafka cluster under the externalKafka parameter⁠. You should also disable the Kafka installation with the kafka.enabled option.

For example, use the parameters below to connect Schema Registry with an existing Kafka installation using SASL authentication:

kafka.enabled=false
externalKafka.brokers=SASL_PLAINTEXT://kafka-0.kafka-headless.default.svc.cluster.local:9092
externalKafka.auth.protocol=sasl
externalKafka.auth.jaas.user=myuser
externalKafka.auth.jaas.password=mypassword

Alternatively, you can use an existing secret with a key "client-passwords":

kafka.enabled=false
externalKafka.brokers=SASL_PLAINTEXT://kafka-0.kafka-headless.default.svc.cluster.local:9092
externalKafka.auth.protocol=sasl
externalKafka.auth.jaas.user=myuser
externalKafka.auth.jaas.existingSecret=my-secret

⁠ Gateway API

This chart provides support for exposing Schema Registry using the Gateway API⁠ and its HTTPRoute resource. If you have a Gateway controller installed on your cluster, such as APISIX, Contour, Envoy Gateway, NGINX Gateway Fabric or Kong Ingress Controller you can utilize the Gateway controller to serve your application. To enable Gateway API integration, set httpRoute.enabled to true. The Gateway to be used can be customized by setting the httpRoute.parentRefs parameter. By default, it will reference a Gateway named gateway in the same namespace as the release.

You can specify the list of hostnames to be mapped to the deployment using the httpRoute.hostnames parameter. Additionally, you can customize the rules used to route the traffic to the service by modifying the httpRoute.matches and httpRoute.filters parameters or adding new rules using the httpRoute.extraRules parameter.

⁠ Ingress

This chart provides support for Ingress resources. If you have an ingress controller installed on your cluster, such as nginx-ingress-controller⁠ or contour⁠ you can utilize the ingress controller to serve your application. To enable Ingress integration, set ingress.enabled to true. The ingress.hostname property can be used to set the host name.

⁠Hosts

Most likely you will only want to have one hostname that maps to this Schema Registry installation. If that's your case, the property ingress.hostname will set it. However, it is possible to have more than one host. To facilitate this, the ingress.extraHosts object is can be specified as an array. You can also use ingress.extraTLS to add the TLS configuration for extra hosts.

For each host indicated at ingress.extraHosts, please indicate a name, path, and any annotations that you may want the ingress controller to know about.

For annotations, please see this document⁠. Not all annotations are supported by all ingress controllers, but this document does a good job of indicating which annotation is supported by many popular ingress controllers.

⁠ Parameters

The following subsections list global, common, and component-specific parameters.

⁠ Global parameters

⁠ Common parameters

⁠ Schema Registry parameters

Note: the README for this chart is longer than the DockerHub length limit of 25000, so it has been trimmed. The full README can be found at https://techdocs.broadcom.com/us/en/vmware-tanzu/bitnami-secure-images/bitnami-secure-images/services/bsi-app-doc/apps-charts-schema-registry-index.html⁠