charts/bitnami/zookeeper

ZooKeeper

ZooKeeper is a centralized service for maintaining configuration information, naming, providing distributed synchronization, and providing group services. All of these kinds of services are used in some form or other by distributed applications.

TL;DR;

$ helm repo add bitnami https://charts.bitnami.com/bitnami
$ helm install my-release bitnami/zookeeper

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. This Helm chart has been tested on top of Bitnami Kubernetes Production Runtime (BKPR). Deploy BKPR to get automated TLS certificates, logging and monitoring for your applications.

Prerequisites

• Kubernetes 1.12+
• Helm 2.12+ or Helm 3.0-beta3+
• PV provisioner support in the underlying infrastructure

Installing the Chart

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

$ helm repo add bitnami https://charts.bitnami.com/bitnami
$ helm install my-release bitnami/zookeeper

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

Uninstalling the Chart

To uninstall/delete the my-release deployment:

$ helm delete my-release

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

Parameters

The following tables lists the configurable parameters of the ZooKeeper chart and their default values.

Parameter	Description	Default
global.imageRegistry	Global Docker image registry	nil
global.imagePullSecrets	Global Docker registry secret names as an array	[] (does not add image pull secrets to deployed pods)
global.storageClass	Global storage class for dynamic provisioning	nil
schedulerName	Kubernetes pod scheduler registry	nil (use the default-scheduler)
image.registry	ZooKeeper image registry	docker.io
image.repository	ZooKeeper Image name	bitnami/zookeeper
image.tag	ZooKeeper Image tag	{TAG_NAME}
image.pullPolicy	ZooKeeper image pull policy	IfNotPresent
image.pullSecrets	Specify docker-registry secret names as an array	[] (does not add image pull secrets to deployed pods)
image.debug	Specify if debug values should be set	false
nameOverride	String to partially override zookeeper.fullname template with a string (will append the release name)	nil
fullnameOverride	String to fully override zookeeper.fullname template with a string	nil
volumePermissions.enabled	Enable init container that changes volume permissions in the data directory (for cases where the default k8s runAsUser and fsUser values do not work)	false
volumePermissions.image.registry	Init container volume-permissions image registry	docker.io
volumePermissions.image.repository	Init container volume-permissions image name	bitnami/minideb
volumePermissions.image.tag	Init container volume-permissions image tag	buster
volumePermissions.image.pullPolicy	Init container volume-permissions image pull policy	Always
volumePermissions.resources	Init container resource requests/limit	nil
extraVolumes	Extra volumes	nil
extraVolumeMounts	Mount extra volume(s)	nil
updateStrategy	Update strategies	RollingUpdate
podDisruptionBudget.maxUnavailable	Max number of pods down simultaneously	1
rollingUpdatePartition	Partition update strategy	nil
clusterDomain	Kubernetes cluster domain	cluster.local
podManagementPolicy	Pod management policy	Parallel
replicaCount	Number of ZooKeeper nodes	1
tickTime	Basic time unit in milliseconds used by ZooKeeper for heartbeats	2000
initLimit	Time the ZooKeeper servers in quorum have to connect to a leader	10
syncLimit	How far out of date a server can be from a leader	5
maxClientCnxns	Number of concurrent connections that a single client may make to a single member	60
maxSessionTimeout	Maximum session timeout in milliseconds that the server will allow the client to negotiate.	40000
autopurge.snapRetainCount	Number of retains snapshots for autopurge	3
autopurge.purgeInterval	The time interval in hours for which the purge task has to be triggered	0
fourlwCommandsWhitelist	A list of comma separated Four Letter Words commands to use	srvr, mntr
listenOnAllIPs	Allow Zookeeper to listen for connections from its peers on all available IP addresses.	false
allowAnonymousLogin	Allow to accept connections from unauthenticated users	yes
auth.existingSecret	Use existing secret (ignores previous password)	nil
auth.enabled	Enable ZooKeeper auth	false
auth.clientUser	User that will use ZooKeeper clients to auth	nil
auth.clientPassword	Password that will use ZooKeeper clients to auth	nil
auth.serverUsers	List of user to be created	nil
auth.serverPasswords	List of passwords to assign to users when created	nil
heapSize	Size in MB for the Java Heap options (Xmx and XMs)	[]
logLevel	Log level of ZooKeeper server	ERROR
jvmFlags	Default JVMFLAGS for the ZooKeeper process	nil
config	Configure ZooKeeper with a custom zoo.conf file	nil
service.type	Kubernetes Service type	ClusterIP
service.port	ZooKeeper port	2181
service.followerPort	ZooKeeper follower port	2888
service.electionPort	ZooKeeper election port	3888
service.publishNotReadyAddresses	If the ZooKeeper headless service should publish DNS records for not ready pods	true
serviceAccount.create	Enable creation of ServiceAccount for zookeeper pod	false
serviceAccount.name	Name of the created serviceAccount	Generated using the zookeeper.fullname template
service.tls.client_enable	Enable tls for client connections	false
service.tls.quorum_enable	Enable tls for quorum protocol	false
service.tls.disable_base_client_port	Remove client port from service definitions.	false
service.tls.client_port	Service port fot tls client connections	3181
service.tls.client_keystore_path	KeyStore file path. Refer to extraVolumes amd extraVolumeMounts for mounting files into the pods	/tls_key_store/key_store_file
service.tls.client_keystore_password	KeyStore password. You can use environment variables.	nil
service.tls.client_truststore_path	TrustStore file path. Refer to extraVolumes amd extraVolumeMounts for mounting files into the pods	/tls_trust_store/trust_store_file
service.tls.client_truststore_password	TrustStore password. You can use environment variables.	nil
service.tls.quorum_keystore_path	KeyStore file path. Refer to extraVolumes amd extraVolumeMounts for mounting files into the pods	/tls_key_store/key_store_file
service.tls.quorum_keystore_password	KeyStore password. You can use environment variables.	nil
service.tls.quorum_truststore_path	TrustStore file path. Refer to extraVolumes amd extraVolumeMounts for mounting files into the pods	/tls_trust_store/trust_store_file
service.tls.quorum_truststore_password	TrustStore password. You can use environment variables.	nil
service.annotations	Annotations for the Service	{}
service.headless.annotations	Annotations for the Headless Service	{}
securityContext.enabled	Enable security context (ZooKeeper master pod)	true
securityContext.fsGroup	Group ID for the container (ZooKeeper master pod)	1001
securityContext.runAsUser	User ID for the container (ZooKeeper master pod)	1001
persistence.enabled	Enable persistence using PVC	true
persistence.existingClaim	Provide an existing PersistentVolumeClaim, the value is evaluated as a template	nil
persistence.storageClass	PVC Storage Class for ZooKeeper volume	nil
persistence.accessModes	PVC Access Mode for ZooKeeper volume	ReadWriteOnce
persistence.size	PVC Storage Request for ZooKeeper volume	8Gi
persistence.annotations	Annotations for the PVC	{}
dataLogDir	Data log directory. Specifying this option will direct zookeeper to write the transaction log to the dataLogDir rather than the dataDir. This allows a dedicated log device to be used, and helps avoid competition between logging and snaphots. Setting this value to an empty string will result in the log being written to the data directory (i.e. Zookeeper's default behavior).	/bitnami/zookeeper/dataLog
persistence.dataLogDir.size	PVC Storage Request for ZooKeeper's dataLogDir volume (if set via .Values.dataLogDir)	8Gi
persistence.dataLogDir.existingClaim	Provide an existing PersistentVolumeClaim for Zookeeper's dataLogDir ((if set via .Values.dataLogDir), the value is evaluated as a template	nil
podLabels	Labels for ZooKeeper pod	{}
podAnnotations	Annotations for ZooKeeper pod	{}
nodeSelector	Node labels for pod assignment	{}
tolerations	Toleration labels for pod assignment	[]
affinity	Map of node/pod affinities	{}
priorityClassName	Name of the existing priority class to be used by zookeeper pods	""
resources	CPU/Memory resource requests/limits	Memory: 256Mi, CPU: 250m
livenessProbe.enabled	Would you like a livenessProbe to be enabled	true
livenessProbe.initialDelaySeconds	Delay before liveness probe is initiated	30
livenessProbe.periodSeconds	How often to perform the probe	10
livenessProbe.timeoutSeconds	When the probe times out	5
livenessProbe.failureThreshold	Minimum consecutive failures for the probe to be considered failed after having succeeded	6
livenessProbe.successThreshold	Minimum consecutive successes for the probe to be considered successful after having failed	1
readinessProbe.enabled	Would you like a readinessProbe to be enabled	true
readinessProbe.initialDelaySeconds	Delay before liveness probe is initiated	5
readinessProbe.periodSeconds	How often to perform the probe	10
readinessProbe.timeoutSeconds	When the probe times out	5
readinessProbe.failureThreshold	Minimum consecutive failures for the probe to be considered failed after having succeeded	6
readinessProbe.successThreshold	Minimum consecutive successes for the probe to be considered successful after having failed	1
metrics.enabled	Enable prometheus to access zookeeper metrics endpoint	false
metrics.port	Port where a Jetty server will expose Prometheus metrics	9141
metrics.podAnnotations	Annotations for enabling prometheus to access the metrics endpoint	{prometheus.io/scrape: "true", prometheus.io/port: "9141"}
metrics.serviceMonitor.enabled	if true, creates a Prometheus Operator ServiceMonitor (also requires metrics.enabled to be true)	false
metrics.serviceMonitor.namespace	Namespace for the ServiceMonitor Resource	The Release Namespace
metrics.serviceMonitor.interval	Interval at which metrics should be scraped.	nil (Prometheus Operator default value)
metrics.serviceMonitor.scrapeTimeout	Timeout after which the scrape is ended	nil (Prometheus Operator default value)
metrics.serviceMonitor.selector	Prometheus instance selector labels	nil
metrics.prometheusRule.enabled	if true, creates a Prometheus Operator PrometheusRule (also requires metrics.enabled to be true and metrics.prometheusRule.rules)	false
metrics.prometheusRule.namespace	Namespace for the PrometheusRule Resource	The Release Namespace
metrics.prometheusRule.selector	Prometheus instance selector labels	nil
metrics.prometheusRule.rules	Prometheus Rule definitions (see values.yaml for examples)	[]
networkPolicy.enabled	Enable NetworkPolicy	false
networkPolicy.allowExternal	Don't require client label for connections	true

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

$ helm install my-release \
  --set auth.clientUser=newUser \
    bitnami/zookeeper

The above command sets the ZooKeeper user to newUser.

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/zookeeper

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.

Production configuration

This chart includes a values-production.yaml file where you can find some parameters oriented to production configuration in comparison to the regular values.yaml. You can use this file instead of the default one.

• Number of ZooKeeper nodes:

- replicaCount: 1
+ replicaCount: 3

• Enable prometheus metrics:

- metrics.enabled: false
+ metrics.enabled: true

Log level

You can configure the ZooKeeper log level using the ZOO_LOG_LEVEL environment variable. By default, it is set to ERROR because of each readiness probe produce an INFO message on connection and a WARN message on disconnection.

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.

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.

Upgrading

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