Apache ZooKeeper provides a reliable, centralized register of configuration data and services for distributed applications.

Overview of Apache ZooKeeper

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/zookeeper

Note: You need to substitute the placeholders REGISTRY_NAME and REPOSITORY_NAME with a reference to your Helm chart registry and repository.

Introduction

This chart bootstraps a ZooKeeper deployment 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.

Prerequisites

• 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/zookeeper

Note: You need to substitute the placeholders REGISTRY_NAME and REPOSITORY_NAME with a reference to your Helm chart registry and repository. For example, in the case of Bitnami, you need to use REGISTRY_NAME=registry-1.docker.io and REPOSITORY_NAME=bitnamicharts.

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

Tip: List all releases using helm list

Configuration and installation details

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.

Update credentials

Bitnami charts configure credentials at first boot. Any further change in the secrets or credentials require manual intervention. Follow these instructions:

• Update the user password following the upstream documentation
• Update the password secret with the new values (replace the SECRET_NAME, CLIENT_PASSWORD and SERVER_PASSWORD placeholders)

kubectl create secret generic SECRET_NAME --from-literal=client-password=CLIENT_PASSWORD --from-literal=server-password=SERVER_PASSWORD --dry-run -o yaml | kubectl apply -f -

Prometheus metrics

This chart can be integrated with Prometheus by setting metrics.enabled to true. This will expose Zookeeper native Prometheus endpoint and a metrics service configurable under the metrics.service section. It will have the necessary annotations to be automatically scraped by Prometheus.

Prometheus requirements

It is necessary to have a working installation of Prometheus or Prometheus Operator for the integration to work. Install the Bitnami Prometheus helm chart or the Bitnami Kube Prometheus helm chart to easily have a working Prometheus in your cluster.

Integration with Prometheus Operator

The chart can deploy ServiceMonitor objects for integration with Prometheus Operator installations. To do so, set the value metrics.serviceMonitor.enabled=true. Ensure that the Prometheus Operator CustomResourceDefinitions are installed in the cluster or it will fail with the following error:

no matches for kind "ServiceMonitor" in version "monitoring.coreos.com/v1"

Install the Bitnami Kube Prometheus helm chart for having the necessary CRDs and the Prometheus Operator.

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.

Configure log level

You can configure the ZooKeeper log level using the ZOO_LOG_LEVEL environment variable or the parameter logLevel. By default, it is set to ERROR because each use of the liveness probe and the readiness probe produces an INFO message on connection and a WARN message on disconnection, generating a high volume of noise in your logs.

In order to remove that log noise so levels can be set to ‘INFO’, two changes must be made.

First, ensure that you are not getting metrics via the deprecated pattern of polling ‘mntr’ on the ZooKeeper client port. The preferred method of polling for Apache ZooKeeper metrics is the ZooKeeper metrics server. This is supported in this chart when setting metrics.enabled to true.

Second, to avoid the connection/disconnection messages from the probes, you can set custom values for these checks which direct them to the ZooKeeper Admin Server instead of the client port. By default, an Admin Server will be started that listens on localhost at port 8080. The following is an example of this use of the Admin Server for probes:

livenessProbe:
  enabled: false
readinessProbe:
  enabled: false
customLivenessProbe:
  exec:
    command: ['/bin/bash', '-c', 'curl -s -m 2 http://localhost:8080/commands/ruok | grep ruok']
  initialDelaySeconds: 30
  periodSeconds: 10
  timeoutSeconds: 5
  successThreshold: 1
  failureThreshold: 6
customReadinessProbe:
  exec:
    command: ['/bin/bash', '-c', 'curl -s -m 2 http://localhost:8080/commands/ruok | grep error | grep null']
  initialDelaySeconds: 5
  periodSeconds: 10
  timeoutSeconds: 5
  successThreshold: 1
  failureThreshold: 6

You can also set the log4j logging level and what log appenders are turned on, by using ZOO_LOG4J_PROP set inside of conf/log4j.properties as zookeeper.root.logger by default to

zookeeper.root.logger=INFO, CONSOLE

the available appender is

• CONSOLE
• ROLLINGFILE
• RFAAUDIT
• TRACEFILE

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.

Persistence

The Bitnami ZooKeeper image stores the ZooKeeper data and configurations at the /bitnami/zookeeper path of the container.

Persistent Volume Claims are used to keep the data across deployments. This is known to work in GCE, AWS, and minikube. See the Parameters section to configure the PVC or to disable persistence.

If you encounter errors when working with persistent volumes, refer to our troubleshooting guide for persistent volumes.

Adjust permissions of persistent volume mountpoint

As the image run as non-root by default, it is necessary to adjust the ownership of the persistent volume so that the container can write data into it.

By default, the chart is configured to use Kubernetes Security Context to automatically change the ownership of the volume. However, this feature does not work in all Kubernetes distributions. As an alternative, this chart supports using an initContainer to change the ownership of the volume before mounting it in the final destination.

You can enable this initContainer by setting volumePermissions.enabled to true.

Configure the data log directory

You can use a dedicated device for logs (instead of using the data directory) to help avoiding competition between logging and snaphots. To do so, set the dataLogDir parameter with the path to be used for writing transaction logs. Alternatively, set this parameter with an empty string and it will result in the log being written to the data directory (Zookeeper’s default behavior).

When using a dedicated device for logs, you can use a PVC to persist the logs. To do so, set persistence.enabled to true. See the Persistence Parameters section for more information.

Set pod affinity

This chart allows you to set custom pod affinity using the affinity parameter. Find more information about pod affinity in the Kubernetes documentation.

As an alternative, you can use any of the preset configurations for pod affinity, pod anti-affinity, and node affinity available at the bitnami/common chart. To do so, set the podAffinityPreset, podAntiAffinityPreset, or nodeAffinityPreset parameters.

Parameters

Global parameters

Common parameters

ZooKeeper chart parameters

Statefulset parameters

Traffic Exposure parameters

Other Parameters

Persistence parameters

Volume Permissions parameters

Metrics parameters

TLS/SSL parameters

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

helm install my-release \
  --set auth.clientUser=newUser \
    oci://REGISTRY_NAME/REPOSITORY_NAME/zookeeper

Note: You need to substitute the placeholders REGISTRY_NAME and REPOSITORY_NAME with a reference to your Helm chart registry and repository. For example, in the case of Bitnami, you need to use REGISTRY_NAME=registry-1.docker.io and REPOSITORY_NAME=bitnamicharts.

The above command sets the ZooKeeper user to newUser.

NOTE: Once this chart is deployed, it is not possible to change the application’s access credentials, such as usernames or passwords, using Helm. To change these application credentials after deployment, delete any persistent volumes (PVs) used by the chart and re-deploy it, or use the application’s built-in administrative tools if available.

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 oci://REGISTRY_NAME/REPOSITORY_NAME/zookeeper

Note: You need to substitute the placeholders REGISTRY_NAME and REPOSITORY_NAME with a reference to your Helm chart registry and repository. For example, in the case of Bitnami, you need to use REGISTRY_NAME=registry-1.docker.io and REPOSITORY_NAME=bitnamicharts. Tip: You can use the default values.yaml

Troubleshooting

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

Upgrading

To 13.7.0

This version introduces image verification for security purposes. To disable it, set global.security.allowInsecureImages to true. More details at GitHub issue.

To 13.0.0

This major bump changes the following security defaults:

• runAsGroup is changed from 0 to 1001
• readOnlyRootFilesystem is set to true
• resourcesPreset is changed from none to the minimum size working in our test suites (NOTE: resourcesPreset is not meant for production usage, but resources adapted to your use case).
• global.compatibility.openshift.adaptSecurityContext is changed from disabled to auto.

This could potentially break any customization or init scripts used in your deployment. If this is the case, change the default values to the previous ones.

To 12.0.0

This new version of the chart includes the new ZooKeeper major version 3.9.x. For more information, please refer to Zookeeper 3.9.0 Release Notes

To 11.0.0

This major version removes commonAnnotations and commonLabels from volumeClaimTemplates. Now annotations and labels can be set in volume claims using persistence.annotations and persistence.labels values. If the previous deployment has already set commonAnnotations and/or commonLabels values, to ensure a clean upgrade from previous version without loosing data, please set persistence.annotations and/or persistence.labels values with the same content as the common values.

To 10.0.0

This new version of the chart adds support for server-server authentication. The chart previously supported client-server authentication, to avoid confusion, the previous parameters have been renamed from auth.* to auth.client.*.

To 9.0.0

This new version of the chart includes the new ZooKeeper major version 3.8.0. Upgrade compatibility is not guaranteed.

To 8.0.0

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

Affected values:

• allowAnonymousLogin is deprecated.
• containerPort, tlsContainerPort, followerContainerPort and electionContainerPort have been regrouped under the containerPorts map.
• service.port, service.tlsClientPort, service.followerPort, and service.electionPort have been regrouped under the service.ports map.
• updateStrategy (string) and rollingUpdatePartition are regrouped under the updateStrategy map.
• podDisruptionBudget.* parameters are renamed to pdb.*.

To 7.0.0

This new version renames the parameters used to configure TLS for both client and quorum.

• service.tls.disable_base_client_port is renamed to service.disableBaseClientPort
• service.tls.client_port is renamed to service.tlsClientPort
• service.tls.client_enable is renamed to tls.client.enabled
• service.tls.client_keystore_path is renamed to tls.client.keystorePath
• service.tls.client_truststore_path is renamed to tls.client.truststorePath
• service.tls.client_keystore_password is renamed to tls.client.keystorePassword
• service.tls.client_truststore_password is renamed to tls.client.truststorePassword
• service.tls.quorum_enable is renamed to tls.quorum.enabled
• service.tls.quorum_keystore_path is renamed to tls.quorum.keystorePath
• service.tls.quorum_truststore_path is renamed to tls.quorum.truststorePath
• service.tls.quorum_keystore_password is renamed to tls.quorum.keystorePassword
• service.tls.quorum_truststore_password is renamed to tls.quorum.truststorePassword

To 6.1.0

This version introduces bitnami/common, a library chart as a dependency. More documentation about this new utility could be found here. Please, make sure that you have updated the chart dependencies before executing any upgrade.

To 6.0.0

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.

To 5.21.0

A couple of parameters related to Zookeeper metrics were renamed or disappeared in favor of new ones:

• metrics.port is renamed to metrics.containerPort.
• metrics.annotations is deprecated in favor of metrics.service.annotations.

To 3.0.0

This new version of the chart includes the new ZooKeeper major version 3.5.5. Note that to perform an automatic upgrade of the application, each node will need to have at least one snapshot file created in the data directory. If not, the new version of the application won’t be able to start the service. Please refer to ZOOKEEPER-3056 in order to find ways to workaround this issue in case you are facing it.

To 2.0.0

Backwards compatibility is not guaranteed unless you modify the labels used on the chart’s statefulsets. Use the workaround below to upgrade from versions previous to 2.0.0. The following example assumes that the release name is zookeeper:

kubectl delete statefulset zookeeper-zookeeper --cascade=false

To 1.0.0

Backwards compatibility is not guaranteed unless you modify the labels used on the chart’s deployments. Use the workaround below to upgrade from versions previous to 1.0.0. The following example assumes that the release name is zookeeper:

kubectl delete statefulset zookeeper-zookeeper --cascade=false

License

Copyright © 2025 Broadcom. The term “Broadcom” refers to Broadcom Inc. and/or its subsidiaries.

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.