Confluent Schema Registry packaged by Bitnami¶

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¶

使用加速地址添加仓库:

helm repo add bitnami "https://helm-charts.itboon.top/bitnami" --force-update
helm update bitnami

helm install my-release bitnami/schema-registry

Introduction¶

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

Bitnami charts can be used with Kubeapps for deployment and management of Helm Charts in clusters.

Looking to use Confluent Schema Registry in production? Try VMware Application Catalog, the enterprise edition of Bitnami Application Catalog.

Prerequisites¶

• Kubernetes 1.19+
• Helm 3.2.0+

Installing the Chart¶

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

helm install my-release bitnami/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.

Tip: List all releases using helm list

Uninstalling the Chart¶

To uninstall/delete the my-release chart:

helm delete my-release

The command removes all the Kubernetes components associated with the chart and deletes the release.

Parameters¶

Global parameters¶

Common parameters¶

Schema Registry parameters¶

Schema Registry statefulset parameters¶

Exposure Parameters¶

RBAC parameters¶

Kafka chart parameters¶

Specify each parameter using the --set key=value[,key=value] argument to helm install. For example,

helm install my-release \
  --set replicaCount=2 \
    bitnami/schema-registry

The above command installs Schema Registry chart with 2 replicas.

Alternatively, a YAML file that specifies the values for the parameters can be provided while installing the chart. For example,

helm install my-release -f values.yaml bitnami/schema-registry

Tip: You can use the default values.yaml

Configuration and installation details¶

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_tls authentication for client communications, while using tls for inter-broker communications. This table shows the available protocols and the security they provide:

Learn more about how to configure Kafka to use the different authentication protocols in the chart documentation.

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

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.

Note: If the JKS files are password protected (recommended), you will need to provide the password to get access to the keystores. To do so, use the kafka.auth.tls.password parameter to provide your password.

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

Note: the command above assumes you already created the truststore and keystores files. This script can help you with the JKS files generation.

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

Adding extra flags¶

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

extraEnvs:
  - 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 paramater. 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 via 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

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 Schema Registry.

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.

Upgrading¶

To 10.0.0¶

This major updates the Kafka subchart to its newest major, 22.0.0. This new version of Kafka uses Kraft by default. For more information on this subchart's major, please refer to Kafka upgrade notes.

To 9.0.0¶

This major updates the Kafka subchart to its newest major, 21.0.0. For more information on this subchart's major, please refer to Kafka upgrade notes.

To 8.0.0¶

This major updates the Kafka subchart to its newest major, 20.0.0. For more information on this subchart's major, please refer to Kafka upgrade notes.

To 6.0.0¶

This major updates the Kafka subchart to its newest major, 19.0.0. For more information on this subchart's major, please refer to Kafka upgrade notes.

To 4.0.0¶

This version bump the version of charts used as dependency in a major. Kafka from 12.X.X to 18.X.X (here you can see the changes introduced in this version).

To 3.0.0¶

This major release renames several values and adds new features, in order to be inline with the rest of assets in the Bitnami charts repository.

Affected values:

• strategyType is replaced by updateStrategy
• service.port is renamed to service.ports.http
• service.nodePort is renamed to service.nodePorts.http
• ingress.certManager is removed, please use ingress.annotationsto add any third party feature

To 2.0.0¶

This version bump the version of charts used as dependency in a major. Kafka from 11.X.X to 12.X.X (here you can see the changes introduced in this version) and common from 0.X.X to 1.X.X (here you can find the changes introduced in this version). Mainly the changes in both subcharts are related to the Helm v2 EOL.

To 1.0.0¶

On November 13, 2020, Helm v2 support was formally finished, this major version is the result of the required changes applied to the Helm Chart to be able to incorporate the different features added in Helm v3 and to be consistent with the Helm project itself regarding the Helm v2 EOL.

What changes were introduced in this major version?¶

• Previous versions of this Helm Chart use apiVersion: v1 (installable by both Helm 2 and 3), this Helm Chart was updated to apiVersion: v2 (installable by Helm 3 only). Here you can find more information about the apiVersion field.
• Move dependency information from the requirements.yaml to the Chart.yaml
• After running helm dependency update, a Chart.lock file is generated containing the same structure used in the previous requirements.lock
• The different fields present in the Chart.yaml file has been ordered alphabetically in a homogeneous way for all the Bitnami Helm Charts

Considerations when upgrading to this version¶

• If you want to upgrade to this version from a previous one installed with Helm v3, you shouldn't face any issues
• If you want to upgrade to this version using Helm v2, this scenario is not supported as this version doesn't support Helm v2 anymore
• If you installed the previous version with Helm v2 and wants to upgrade to this version with Helm v3, please refer to the official Helm documentation about migrating from Helm v2 to v3

Useful links¶

• https://docs.bitnami.com/tutorials/resolve-helm2-helm3-post-migration-issues/
• https://helm.sh/docs/topics/v2_v3_migration/
• https://helm.sh/blog/migrate-from-helm-v2-to-helm-v3/

Troubleshooting¶

Find more information about how to deal with common errors related to Bitnami's Helm charts in this troubleshooting guide.

License¶

Copyright © 2023 VMware, Inc.

Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at

http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.