Apache ZooKeeper provides a reliable, centralized register of configuration data and services for distributed applications.
[Overview of Apache ZooKeeper](https://zookeeper.apache.org)
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.
This chart bootstraps a [ZooKeeper](https://github.com/bitnami/containers/tree/main/bitnami/zookeeper) deployment on a [Kubernetes](https://kubernetes.io) cluster using the [Helm](https://helm.sh) package manager.
Bitnami charts can be used with [Kubeapps](https://kubeapps.dev/) for deployment and management of Helm Charts in clusters.
## Prerequisites
- Kubernetes 1.19+
- Helm 3.2.0+
- PV provisioner support in the underlying infrastructure
## Installing the Chart
To install the chart with the release name `my-release`:
These commands deploy ZooKeeper on the Kubernetes cluster in the default configuration. The [Parameters](#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` deployment:
```console
$ helm delete my-release
```
The command removes all the Kubernetes components associated with the chart and deletes the release.
| `snapCount` | The number of transactions recorded in the transaction log before a snapshot can be taken (and the transaction log rolled) | `100000` |
| `maxClientCnxns` | Limits the number of concurrent connections that a single client may make to a single member of the ZooKeeper ensemble | `60` |
| `maxSessionTimeout` | Maximum session timeout (in milliseconds) that the server will allow the client to negotiate | `40000` |
| `heapSize` | Size (in MB) for the Java Heap options (Xmx and Xms) | `1024` |
| `fourlwCommandsWhitelist` | A list of comma separated Four Letter Words commands that can be executed | `srvr, mntr, ruok` |
| `podLabels` | Extra labels for ZooKeeper pods | `{}` |
| `podAnnotations` | Annotations for ZooKeeper pods | `{}` |
| `podAffinityPreset` | Pod affinity preset. Ignored if `affinity` is set. Allowed values: `soft` or `hard` | `""` |
| `podAntiAffinityPreset` | Pod anti-affinity preset. Ignored if `affinity` is set. Allowed values: `soft` or `hard` | `soft` |
| `nodeAffinityPreset.type` | Node affinity preset type. Ignored if `affinity` is set. Allowed values: `soft` or `hard` | `""` |
| `nodeAffinityPreset.key` | Node label key to match Ignored if `affinity` is set. | `""` |
| `nodeAffinityPreset.values` | Node label values to match. Ignored if `affinity` is set. | `[]` |
| `affinity` | Affinity for pod assignment | `{}` |
| `nodeSelector` | Node labels for pod assignment | `{}` |
| `tolerations` | Tolerations for pod assignment | `[]` |
| `topologySpreadConstraints` | Topology Spread Constraints for pod assignment spread across your cluster among failure-domains. Evaluated as a template | `[]` |
| `podManagementPolicy` | StatefulSet controller supports relax its ordering guarantees while preserving its uniqueness and identity guarantees. There are two valid pod management policies: `OrderedReady` and `Parallel` | `Parallel` |
| `priorityClassName` | Name of the existing priority class to be used by ZooKeeper pods, priority class needs to be created beforehand | `""` |
| `schedulerName` | Kubernetes pod scheduler registry | `""` |
| `updateStrategy.type` | ZooKeeper statefulset strategy type | `RollingUpdate` |
| `volumePermissions.image.digest` | Init container volume-permissions image digest in the way sha256:aa.... Please note this parameter, if set, will override the tag | `""` |
| `tls.client.existingSecret` | Name of the existing secret containing the TLS certificates for ZooKeeper client communications | `""` |
| `tls.client.existingSecretKeystoreKey` | The secret key from the tls.client.existingSecret containing the Keystore. | `""` |
| `tls.client.existingSecretTruststoreKey` | The secret key from the tls.client.existingSecret containing the Truststore. | `""` |
| `tls.client.keystorePath` | Location of the KeyStore file used for Client connections | `/opt/bitnami/zookeeper/config/certs/client/zookeeper.keystore.jks` |
| `tls.client.truststorePath` | Location of the TrustStore file used for Client connections | `/opt/bitnami/zookeeper/config/certs/client/zookeeper.truststore.jks` |
| `tls.client.passwordsSecretKeystoreKey` | The secret key from the tls.client.passwordsSecretName containing the password for the Keystore. | `""` |
| `tls.client.passwordsSecretTruststoreKey` | The secret key from the tls.client.passwordsSecretName containing the password for the Truststore. | `""` |
| `tls.client.keystorePassword` | Password to access KeyStore if needed | `""` |
| `tls.client.truststorePassword` | Password to access TrustStore if needed | `""` |
| `tls.quorum.enabled` | Enable TLS for quorum protocol | `false` |
| `tls.quorum.auth` | SSL Quorum Client auth. Can be "none", "want" or "need". | `none` |
| `tls.quorum.autoGenerated` | Create self-signed TLS certificates. Currently only supports PEM certificates. | `false` |
| `tls.quorum.existingSecret` | Name of the existing secret containing the TLS certificates for ZooKeeper quorum protocol | `""` |
| `tls.quorum.existingSecretKeystoreKey` | The secret key from the tls.quorum.existingSecret containing the Keystore. | `""` |
| `tls.quorum.existingSecretTruststoreKey` | The secret key from the tls.quorum.existingSecret containing the Truststore. | `""` |
| `tls.quorum.keystorePath` | Location of the KeyStore file used for Quorum protocol | `/opt/bitnami/zookeeper/config/certs/quorum/zookeeper.keystore.jks` |
| `tls.quorum.truststorePath` | Location of the TrustStore file used for Quorum protocol | `/opt/bitnami/zookeeper/config/certs/quorum/zookeeper.truststore.jks` |
| `tls.quorum.passwordsSecretKeystoreKey` | The secret key from the tls.quorum.passwordsSecretName containing the password for the Keystore. | `""` |
| `tls.quorum.passwordsSecretTruststoreKey` | The secret key from the tls.quorum.passwordsSecretName containing the password for the Truststore. | `""` |
| `tls.quorum.keystorePassword` | Password to access KeyStore if needed | `""` |
| `tls.quorum.truststorePassword` | Password to access TrustStore if needed | `""` |
| `tls.resources.limits` | The resources limits for the TLS init container | `{}` |
| `tls.resources.requests` | The requested resources for the TLS init container | `{}` |
Specify each parameter using the `--set key=value[,key=value]` argument to `helm install`. For example,
```console
$ helm install my-release \
--set auth.clientUser=newUser \
my-repo/zookeeper
```
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,
> **Tip**: You can use the default [values.yaml](values.yaml)
## Configuration and installation details
### [Rolling vs Immutable tags](https://docs.bitnami.com/containers/how-to/understand-rolling-tags-containers/)
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:
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
```console
zookeeper.root.logger=INFO, CONSOLE
```
the available appender is
- CONSOLE
- ROLLINGFILE
- RFAAUDIT
- TRACEFILE
## Persistence
The [Bitnami ZooKeeper](https://github.com/bitnami/containers/tree/main/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](#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](https://docs.bitnami.com/kubernetes/faq/troubleshooting/troubleshooting-persistence-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](#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](https://kubernetes.io/docs/concepts/configuration/assign-pod-node/#affinity-and-anti-affinity).
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](https://github.com/bitnami/charts/tree/main/bitnami/common#affinities) chart. To do so, set the `podAffinityPreset`, `podAntiAffinityPreset`, or `nodeAffinityPreset` parameters.
## Troubleshooting
Find more information about how to deal with common errors related to Bitnami's Helm charts in [this troubleshooting guide](https://docs.bitnami.com/general/how-to/troubleshoot-helm-chart-issues).
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.
The chart previously supported client-server authentication, to avoid confusion, the previous parameters have been renamed from `auth.*` to `auth.client.*`.
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](https://helm.sh/docs/topics/library_charts/#helm) as a dependency. More documentation about this new utility could be found [here](https://github.com/bitnami/charts/tree/main/bitnami/common#bitnami-common-library-chart). 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](https://github.com/helm/charts#status-of-the-project), 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.
[Learn more about this change and related upgrade considerations](https://docs.bitnami.com/kubernetes/infrastructure/zookeeper/administration/upgrade-helm3/).
### 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](https://issues.apache.org/jira/browse/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`:
