openreplay/ee/scripts/helm/db/kafka/charts/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 per section/component:

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

Common parameters

Parameter	Description	Default
nameOverride	String to partially override zookeeper.fullname	nil
fullnameOverride	String to fully override zookeeper.fullname	nil
clusterDomain	Default Kubernetes cluster domain	cluster.local
commonLabels	Labels to add to all deployed objects	{}
commonAnnotations	Annotations to add to all deployed objects	{}
schedulerName	Kubernetes pod scheduler registry	nil (use the default-scheduler)

Zookeeper chart parameters

Parameter	Description	Default
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
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
dataLogDir	Data log directory	""

Statefulset parameters

Parameter	Description	Default
replicaCount	Number of ZooKeeper nodes	1
updateStrategy	Update strategy for the statefulset	RollingUpdate
rollingUpdatePartition	Partition update strategy	nil
podManagementPolicy	Pod management policy	Parallel
podLabels	ZooKeeper pod labels	{} (evaluated as a template)
podAnnotations	ZooKeeper Pod annotations	{} (evaluated as a template)
affinity	Affinity for pod assignment	{} (evaluated as a template)
nodeSelector	Node labels for pod assignment	{} (evaluated as a template)
tolerations	Tolerations for pod assignment	[] (evaluated as a template)
priorityClassName	Name of the existing priority class to be used by ZooKeeper pods	""
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
resources	CPU/Memory resource requests/limits	Memory: 256Mi, CPU: 250m
livenessProbe	Liveness probe configuration for ZooKeeper	Check values.yaml file
readinessProbe	Readiness probe configuration for ZooKeeper	Check values.yaml file
extraVolumes	Extra volumes	nil
extraVolumeMounts	Mount extra volume(s)	nil
podDisruptionBudget.maxUnavailable	Max number of pods down simultaneously	1

Exposure parameters

Parameter	Description	Default
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	The name of the service account to use. If not set and create is true, a name is generated	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 for tls client connections	3181
service.tls.client_keystore_path	KeyStore file path. Refer to extraVolumes and 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 and 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 and 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 and 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	{}
networkPolicy.enabled	Enable NetworkPolicy	false
networkPolicy.allowExternal	Don't require client label for connections	true

Persistence parameters

Parameter	Description	Default
persistence.enabled	Enable Zookeeper data persistence using PVC	true
persistence.existingClaim	Provide an existing PersistentVolumeClaim	nil (evaluated as a template)
persistence.storageClass	PVC Storage Class for ZooKeeper data volume	nil
persistence.accessMode	PVC Access Mode for ZooKeeper data volume	ReadWriteOnce
persistence.size	PVC Storage Request for ZooKeeper data volume	8Gi
persistence.annotations	Annotations for the PVC	{} (evaluated as a template)
persistence.dataLogDir.size	PVC Storage Request for ZooKeeper's Data log directory	8Gi
persistence.dataLogDir.existingClaim	Provide an existing PersistentVolumeClaim for Zookeeper's Data log directory	nil (evaluated as a template)

Volume Permissions parameters

Parameter	Description	Default
volumePermissions.enabled	Enable init container that changes the owner and group of the persistent volume(s) mountpoint to runAsUser:fsGroup	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

Metrics parameters

Parameter	Description	Default
metrics.enabled	Enable prometheus to access zookeeper metrics endpoint	false
metrics.containerPort	Port where a Jetty server will expose Prometheus metrics	9141
metrics.service.type	Kubernetes service type (ClusterIP, NodePort or LoadBalancer) for Jetty server exposing Prometheus metrics	ClusterIP
metrics.service.port	Prometheus metrics service port	9141
metrics.service.annotations	Service annotations for Prometheus to auto-discover 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)	[]

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.

Data Log Directory

You can use a dedicated device for logs (instead of using the data directory) to help avoiding competition between logging and snapshots. 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 an it 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.

Upgrading

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