Bitnami package for Redis(R) Cluster

Redis(R) is an open source, scalable, distributed in-memory cache for applications. It can be used to store and serve data in the form of strings, hashes, lists, sets and sorted sets.

Overview of Redis® Cluster

Disclaimer: Redis is a registered trademark of Redis Ltd. Any rights therein are reserved to Redis Ltd. Any use by Bitnami is for referential purposes only and does not indicate any sponsorship, endorsement, or affiliation between Redis Ltd.

TL;DR

helm install my-release oci://registry-1.docker.io/bitnamicharts/redis-cluster

Introduction

This chart bootstraps a Redis® 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.

Choose between Redis® Helm Chart and Redis® Cluster Helm Chart

You can choose any of the two Redis® Helm charts for deploying a Redis® cluster. While Redis® Helm Chart will deploy a master-slave cluster using Redis® Sentinel, the Redis® Cluster Helm Chart will deploy a Redis® Cluster with sharding. The main features of each chart are the following:

Redis®	Redis® Cluster
Supports multiple databases	Supports only one database. Better if you have a big dataset
Single write point (single master)	Multiple write points (multiple masters)

Looking to use Redisreg; Cluster in production? Try VMware Application Catalog, the enterprise edition of Bitnami Application Catalog.

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:

helm install my-release oci://registry-1.docker.io/bitnamicharts/redis-cluster

The command deploys Redis® on the Kubernetes cluster in the default configuration. The Parameters section lists the parameters that can be configured during installation.

NOTE: if you get a timeout error waiting for the hook to complete increase the default timeout (300s) to a higher one, for example:

helm install --timeout 600s myrelease oci://registry-1.docker.io/bitnamicharts/redis-cluster

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

Global parameters

Name	Description	Value
global.imageRegistry	Global Docker image registry	""
global.imagePullSecrets	Global Docker registry secret names as an array	[]
global.storageClass	Global StorageClass for Persistent Volume(s)	""
global.redis.password	Redis® password (overrides password)	""

Redis® Cluster Common parameters

Name	Description	Value
nameOverride	String to partially override common.names.fullname template (will maintain the release name)	""
fullnameOverride	String to fully override common.names.fullname template	""
clusterDomain	Kubernetes Cluster Domain	cluster.local
commonAnnotations	Annotations to add to all deployed objects	{}
commonLabels	Labels to add to all deployed objects	{}
extraDeploy	Array of extra objects to deploy with the release (evaluated as a template)	[]
diagnosticMode.enabled	Enable diagnostic mode (all probes will be disabled and the command will be overridden)	false
diagnosticMode.command	Command to override all containers in the deployment	["sleep"]
diagnosticMode.args	Args to override all containers in the deployment	["infinity"]
image.registry	Redis® cluster image registry	docker.io
image.repository	Redis® cluster image repository	bitnami/redis-cluster
image.tag	Redis® cluster image tag (immutable tags are recommended)	7.0.12-debian-11-r13
image.digest	Redis® cluster image digest in the way sha256:aa.... Please note this parameter, if set, will override the tag	""
image.pullPolicy	Redis® cluster image pull policy	IfNotPresent
image.pullSecrets	Specify docker-registry secret names as an array	[]
image.debug	Enable image debug mode	false
networkPolicy.enabled	Enable NetworkPolicy	false
networkPolicy.allowExternal	The Policy model to apply. Don't require client label for connections	true
networkPolicy.ingressNSMatchLabels	Allow connections from other namespacess. Just set label for namespace and set label for pods (optional).	{}
networkPolicy.ingressNSPodMatchLabels	For other namespaces match by pod labels and namespace labels	{}
serviceAccount.create	Specifies whether a ServiceAccount should be created	false
serviceAccount.name	The name of the ServiceAccount to create	""
serviceAccount.annotations	Annotations for Cassandra Service Account	{}
serviceAccount.automountServiceAccountToken	Automount API credentials for a service account.	false
rbac.create	Specifies whether RBAC resources should be created	false
rbac.role.rules	Rules to create. It follows the role specification	[]
podSecurityContext.enabled	Enable Redis® pod Security Context	true
podSecurityContext.fsGroup	Group ID for the pods	1001
podSecurityContext.runAsUser	User ID for the pods	1001
podSecurityContext.sysctls	Set namespaced sysctls for the pods	[]
podDisruptionBudget	Limits the number of pods of the replicated application that are down simultaneously from voluntary disruptions	{}
minAvailable	Min number of pods that must still be available after the eviction	""
maxUnavailable	Max number of pods that can be unavailable after the eviction	""
containerSecurityContext.enabled	Enable Containers' Security Context	true
containerSecurityContext.runAsUser	User ID for the containers.	1001
containerSecurityContext.runAsNonRoot	Run container as non root	true
usePassword	Use password authentication	true
password	Redis® password (ignored if existingSecret set)	""
existingSecret	Name of existing secret object (for password authentication)	""
existingSecretPasswordKey	Name of key containing password to be retrieved from the existing secret	""
usePasswordFile	Mount passwords as files instead of environment variables	false
tls.enabled	Enable TLS support for replication traffic	false
tls.authClients	Require clients to authenticate or not	true
tls.autoGenerated	Generate automatically self-signed TLS certificates	false
tls.existingSecret	The name of the existing secret that contains the TLS certificates	""
tls.certificatesSecret	DEPRECATED. Use tls.existingSecret instead	""
tls.certFilename	Certificate filename	""
tls.certKeyFilename	Certificate key filename	""
tls.certCAFilename	CA Certificate filename	""
tls.dhParamsFilename	File containing DH params (in order to support DH based ciphers)	""
service.ports.redis	Kubernetes Redis service port	6379
service.nodePorts.redis	Node port for Redis	""
service.extraPorts	Extra ports to expose in the service (normally used with the sidecar value)	[]
service.annotations	Provide any additional annotations which may be required.	{}
service.labels	Additional labels for redis service	{}
service.type	Service type for default redis service	ClusterIP
service.clusterIP	Service Cluster IP	""
service.loadBalancerIP	Load balancer IP if service.type is LoadBalancer	""
service.loadBalancerSourceRanges	Service Load Balancer sources	[]
service.externalTrafficPolicy	Service external traffic policy	Cluster
service.sessionAffinity	Session Affinity for Kubernetes service, can be "None" or "ClientIP"	None
service.sessionAffinityConfig	Additional settings for the sessionAffinity	{}
service.headless.annotations	Annotations for the headless service.	{}
persistence.enabled	Enable persistence on Redis®	true
persistence.path	Path to mount the volume at, to use other images Redis® images.	/bitnami/redis/data
persistence.subPath	The subdirectory of the volume to mount to, useful in dev environments and one PV for multiple services	""
persistence.storageClass	Storage class of backing PVC	""
persistence.annotations	Persistent Volume Claim annotations	{}
persistence.accessModes	Persistent Volume Access Modes	["ReadWriteOnce"]
persistence.size	Size of data volume	8Gi
persistence.matchLabels	Persistent Volume selectors	{}
persistence.matchExpressions	matchExpressions Persistent Volume selectors	{}
persistentVolumeClaimRetentionPolicy.enabled	Controls if and how PVCs are deleted during the lifecycle of a StatefulSet	false
persistentVolumeClaimRetentionPolicy.whenScaled	Volume retention behavior when the replica count of the StatefulSet is reduced	Retain
persistentVolumeClaimRetentionPolicy.whenDeleted	Volume retention behavior that applies when the StatefulSet is deleted	Retain
volumePermissions.enabled	Enable init container that changes volume permissions in the registry (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 repository	bitnami/os-shell
volumePermissions.image.tag	Init container volume-permissions image tag	11-debian-11-r16
volumePermissions.image.digest	Init container volume-permissions image digest in the way sha256:aa.... Please note this parameter, if set, will override the tag	""
volumePermissions.image.pullPolicy	Init container volume-permissions image pull policy	IfNotPresent
volumePermissions.image.pullSecrets	Specify docker-registry secret names as an array	[]
volumePermissions.containerSecurityContext.enabled	Enable Containers' Security Context	true
volumePermissions.containerSecurityContext.runAsUser	User ID for the containers.	0
volumePermissions.containerSecurityContext.privileged	Run container as privileged	false
volumePermissions.resources.limits	The resources limits for the container	{}
volumePermissions.resources.requests	The requested resources for the container	{}
podSecurityPolicy.create	Whether to create a PodSecurityPolicy. WARNING: PodSecurityPolicy is deprecated in Kubernetes v1.21 or later, unavailable in v1.25 or later	false

Redis® statefulset parameters

Name	Description	Value
redis.command	Redis® entrypoint string. The command redis-server is executed if this is not provided	[]
redis.args	Arguments for the provided command if needed	[]
redis.updateStrategy.type	Argo Workflows statefulset strategy type	RollingUpdate
redis.updateStrategy.rollingUpdate.partition	Partition update strategy	0
redis.podManagementPolicy	Statefulset Pod management policy, it needs to be Parallel to be able to complete the cluster join	Parallel
redis.hostAliases	Deployment pod host aliases	[]
redis.hostNetwork	Host networking requested for this pod. Use the host's network namespace.	false
redis.useAOFPersistence	Whether to use AOF Persistence mode or not	yes
redis.containerPorts.redis	Redis® port	6379
redis.containerPorts.bus	The busPort should be obtained adding 10000 to the redisPort. By default: 10000 + 6379 = 16379	16379
redis.lifecycleHooks	LifecycleHook to set additional configuration before or after startup. Evaluated as a template	{}
redis.extraVolumes	Extra volumes to add to the deployment	[]
redis.extraVolumeMounts	Extra volume mounts to add to the container	[]
redis.customLivenessProbe	Override default liveness probe	{}
redis.customReadinessProbe	Override default readiness probe	{}
redis.customStartupProbe	Custom startupProbe that overrides the default one	{}
redis.initContainers	Extra init containers to add to the deployment	[]
redis.sidecars	Extra sidecar containers to add to the deployment	[]
redis.podLabels	Additional labels for Redis® pod	{}
redis.priorityClassName	Redis® Master pod priorityClassName	""
redis.defaultConfigOverride	Optional default Redis® configuration for the nodes	""
redis.configmap	Additional Redis® configuration for the nodes	""
redis.extraEnvVars	An array to add extra environment variables	[]
redis.extraEnvVarsCM	ConfigMap with extra environment variables	""
redis.extraEnvVarsSecret	Secret with extra environment variables	""
redis.podAnnotations	Redis® additional annotations	{}
redis.resources.limits	The resources limits for the container	{}
redis.resources.requests	The requested resources for the container	{}
redis.schedulerName	Use an alternate scheduler, e.g. "stork".	""
redis.shareProcessNamespace	Enable shared process namespace in a pod.	false
redis.livenessProbe.enabled	Enable livenessProbe	true
redis.livenessProbe.initialDelaySeconds	Initial delay seconds for livenessProbe	5
redis.livenessProbe.periodSeconds	Period seconds for livenessProbe	5
redis.livenessProbe.timeoutSeconds	Timeout seconds for livenessProbe	5
redis.livenessProbe.failureThreshold	Failure threshold for livenessProbe	5
redis.livenessProbe.successThreshold	Success threshold for livenessProbe	1
redis.readinessProbe.enabled	Enable readinessProbe	true
redis.readinessProbe.initialDelaySeconds	Initial delay seconds for readinessProbe	5
redis.readinessProbe.periodSeconds	Period seconds for readinessProbe	5
redis.readinessProbe.timeoutSeconds	Timeout seconds for readinessProbe	1
redis.readinessProbe.failureThreshold	Failure threshold for readinessProbe	5
redis.readinessProbe.successThreshold	Success threshold for readinessProbe	1
redis.startupProbe.enabled	Enable startupProbe	false
redis.startupProbe.path	Path to check for startupProbe	/
redis.startupProbe.initialDelaySeconds	Initial delay seconds for startupProbe	300
redis.startupProbe.periodSeconds	Period seconds for startupProbe	10
redis.startupProbe.timeoutSeconds	Timeout seconds for startupProbe	5
redis.startupProbe.failureThreshold	Failure threshold for startupProbe	6
redis.startupProbe.successThreshold	Success threshold for startupProbe	1
redis.podAffinityPreset	Redis® pod affinity preset. Ignored if redis.affinity is set. Allowed values: soft or hard	""
redis.podAntiAffinityPreset	Redis® pod anti-affinity preset. Ignored if redis.affinity is set. Allowed values: soft or hard	soft
redis.nodeAffinityPreset.type	Redis® node affinity preset type. Ignored if redis.affinity is set. Allowed values: soft or hard	""
redis.nodeAffinityPreset.key	Redis® node label key to match Ignored if redis.affinity is set.	""
redis.nodeAffinityPreset.values	Redis® node label values to match. Ignored if redis.affinity is set.	[]
redis.affinity	Affinity settings for Redis® pod assignment	{}
redis.nodeSelector	Node labels for Redis® pods assignment	{}
redis.tolerations	Tolerations for Redis® pods assignment	[]
redis.topologySpreadConstraints	Pod topology spread constraints for Redis® pod	[]

Cluster update job parameters

Name	Description	Value
updateJob.activeDeadlineSeconds	Number of seconds the Job to create the cluster will be waiting for the Nodes to be ready.	600
updateJob.command	Container command (using container default if not set)	[]
updateJob.args	Container args (using container default if not set)	[]
updateJob.hostAliases	Deployment pod host aliases	[]
updateJob.annotations	Job annotations	{}
updateJob.podAnnotations	Job pod annotations	{}
updateJob.podLabels	Pod extra labels	{}
updateJob.extraEnvVars	An array to add extra environment variables	[]
updateJob.extraEnvVarsCM	ConfigMap containing extra environment variables	""
updateJob.extraEnvVarsSecret	Secret containing extra environment variables	""
updateJob.extraVolumes	Extra volumes to add to the deployment	[]
updateJob.extraVolumeMounts	Extra volume mounts to add to the container	[]
updateJob.initContainers	Extra init containers to add to the deployment	[]
updateJob.podAffinityPreset	Update job pod affinity preset. Ignored if updateJob.affinity is set. Allowed values: soft or hard	""
updateJob.podAntiAffinityPreset	Update job pod anti-affinity preset. Ignored if updateJob.affinity is set. Allowed values: soft or hard	soft
updateJob.nodeAffinityPreset.type	Update job node affinity preset type. Ignored if updateJob.affinity is set. Allowed values: soft or hard	""
updateJob.nodeAffinityPreset.key	Update job node label key to match Ignored if updateJob.affinity is set.	""
updateJob.nodeAffinityPreset.values	Update job node label values to match. Ignored if updateJob.affinity is set.	[]
updateJob.affinity	Affinity for update job pods assignment	{}
updateJob.nodeSelector	Node labels for update job pods assignment	{}
updateJob.tolerations	Tolerations for update job pods assignment	[]
updateJob.priorityClassName	Priority class name	""
updateJob.resources.limits	The resources limits for the container	{}
updateJob.resources.requests	The requested resources for the container	{}

Cluster management parameters

Name	Description	Value
cluster.init	Enable the initialization of the Redis® Cluster	true
cluster.nodes	The number of master nodes should always be >= 3, otherwise cluster creation will fail	6
cluster.replicas	Number of replicas for every master in the cluster	1
cluster.externalAccess.enabled	Enable access to the Redis	false
cluster.externalAccess.service.type	Type for the services used to expose every Pod	LoadBalancer
cluster.externalAccess.service.port	Port for the services used to expose every Pod	6379
cluster.externalAccess.service.loadBalancerIP	Array of load balancer IPs for each Redis® node. Length must be the same as cluster.nodes	[]
cluster.externalAccess.service.loadBalancerSourceRanges	Service Load Balancer sources	[]
cluster.externalAccess.service.annotations	Annotations to add to the services used to expose every Pod of the Redis® Cluster	{}
cluster.update.addNodes	Boolean to specify if you want to add nodes after the upgrade	false
cluster.update.currentNumberOfNodes	Number of currently deployed Redis® nodes	6
cluster.update.currentNumberOfReplicas	Number of currently deployed Redis® replicas	1
cluster.update.newExternalIPs	External IPs obtained from the services for the new nodes to add to the cluster	[]

Metrics sidecar parameters

Name	Description	Value
metrics.enabled	Start a side-car prometheus exporter	false
metrics.image.registry	Redis® exporter image registry	docker.io
metrics.image.repository	Redis® exporter image name	bitnami/redis-exporter
metrics.image.tag	Redis® exporter image tag	1.52.0-debian-11-r0
metrics.image.digest	Redis® exporter image digest in the way sha256:aa.... Please note this parameter, if set, will override the tag	""
metrics.image.pullPolicy	Redis® exporter image pull policy	IfNotPresent
metrics.image.pullSecrets	Specify docker-registry secret names as an array	[]
metrics.resources	Metrics exporter resource requests and limits	{}
metrics.extraArgs	Extra arguments for the binary; possible values here	{}
metrics.extraEnvVars	Array with extra environment variables to add to Redis® exporter	[]
metrics.podAnnotations	Additional annotations for Metrics exporter pod	{}
metrics.podLabels	Additional labels for Metrics exporter pod	{}
metrics.containerSecurityContext.enabled	Enable Metrics Containers' Security Context	false
metrics.containerSecurityContext.allowPrivilegeEscalation	Allow Privilege Escalation for metrics container	false
metrics.serviceMonitor.enabled	If true, creates a Prometheus Operator ServiceMonitor (also requires metrics.enabled to be true)	false
metrics.serviceMonitor.namespace	Optional namespace which Prometheus is running in	""
metrics.serviceMonitor.interval	How frequently to scrape metrics (use by default, falling back to Prometheus' default)	""
metrics.serviceMonitor.scrapeTimeout	Timeout after which the scrape is ended	""
metrics.serviceMonitor.selector	Prometheus instance selector labels	{}
metrics.serviceMonitor.labels	ServiceMonitor extra labels	{}
metrics.serviceMonitor.annotations	ServiceMonitor annotations	{}
metrics.serviceMonitor.jobLabel	The name of the label on the target service to use as the job name in prometheus.	""
metrics.serviceMonitor.relabelings	RelabelConfigs to apply to samples before scraping	[]
metrics.serviceMonitor.metricRelabelings	MetricRelabelConfigs to apply to samples before ingestion	[]
metrics.prometheusRule.enabled	Set this to true to create prometheusRules for Prometheus operator	false
metrics.prometheusRule.additionalLabels	Additional labels that can be used so prometheusRules will be discovered by Prometheus	{}
metrics.prometheusRule.namespace	namespace where prometheusRules resource should be created	""
metrics.prometheusRule.rules	Create specified rules, check values for an example.	[]
metrics.priorityClassName	Metrics exporter pod priorityClassName	""
metrics.service.type	Kubernetes Service type (redis metrics)	ClusterIP
metrics.service.loadBalancerIP	Use serviceLoadBalancerIP to request a specific static IP, otherwise leave blank	""
metrics.service.annotations	Annotations for the services to monitor.	{}
metrics.service.labels	Additional labels for the metrics service	{}
metrics.service.clusterIP	Service Cluster IP	""

Sysctl Image parameters

Name	Description	Value
sysctlImage.enabled	Enable an init container to modify Kernel settings	false
sysctlImage.command	sysctlImage command to execute	[]
sysctlImage.registry	sysctlImage Init container registry	docker.io
sysctlImage.repository	sysctlImage Init container repository	bitnami/os-shell
sysctlImage.tag	sysctlImage Init container tag	11-debian-11-r16
sysctlImage.digest	sysctlImage Init container digest in the way sha256:aa.... Please note this parameter, if set, will override the tag	""
sysctlImage.pullPolicy	sysctlImage Init container pull policy	IfNotPresent
sysctlImage.pullSecrets	Specify docker-registry secret names as an array	[]
sysctlImage.mountHostSys	Mount the host /sys folder to /host-sys	false
sysctlImage.containerSecurityContext.enabled	Enable Containers' Security Context	true
sysctlImage.containerSecurityContext.runAsUser	User ID for the containers.	0
sysctlImage.containerSecurityContext.privileged	Run privileged as privileged	true
sysctlImage.resources.limits	The resources limits for the container	{}
sysctlImage.resources.requests	The requested resources for the container	{}

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

helm install my-release \
  --set password=secretpassword \
    oci://registry-1.docker.io/bitnamicharts/redis-cluster

The above command sets the Redis® server password to secretpassword.

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-1.docker.io/bitnamicharts/redis-cluster

Tip: You can use the default values.yaml Note for minikube users: Current versions of minikube (v0.24.1 at the time of writing) provision hostPath persistent volumes that are only writable by root. Using chart defaults cause pod failure for the Redis® pod as it attempts to write to the /bitnami directory. See minikube issue 1990 for more information.

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.

Use a different Redis® version

To modify the application version used in this chart, specify a different version of the image using the image.tag parameter and/or a different repository using the image.repository parameter. Refer to the chart documentation for more information on these parameters and how to use them with images from a private registry.

Cluster topology

To successfully set the cluster up, it will need to have at least 3 master nodes. The total number of nodes is calculated like- nodes = numOfMasterNodes + numOfMasterNodes * replicas. Hence, the defaults cluster.nodes = 6 and cluster.replicas = 1 means, 3 master and 3 replica nodes will be deployed by the chart.

By default the Redis® Cluster is not accessible from outside the Kubernetes cluster, to access the Redis® Cluster from outside you have to set cluster.externalAccess.enabled=true at deployment time. It will create in the first installation only 6 LoadBalancer services, one for each Redis® node, once you have the external IPs of each service you will need to perform an upgrade passing those IPs to the cluster.externalAccess.service.loadbalancerIP array.

The replicas will be read-only replicas of the masters. By default only one service is exposed (when not using the external access mode). You will connect your client to the exposed service, regardless you need to read or write. When a write operation arrives to a replica it will redirect the client to the proper master node. For example, using redis-cli you will need to provide the -c flag for redis-cli to follow the redirection automatically.

Using the external access mode, you can connect to any of the pods and the slaves will redirect the client in the same way as explained before, but the all the IPs will be public.

In case the master crashes, one of his slaves will be promoted to master. The slots stored by the crashed master will be unavailable until the slave finish the promotion. If a master and all his slaves crash, the cluster will be down until one of them is up again. To avoid downtime, it is possible to configure the number of Redis® nodes with cluster.nodes and the number of replicas that will be assigned to each master with cluster.replicas. For example:

• cluster.nodes=9 ( 3 master plus 2 replicas for each master)
• cluster.replicas=2

Providing the values above, the cluster will have 3 masters and, each master, will have 2 replicas.

NOTE: By default cluster.init will be set to true in order to initialize the Redis® Cluster in the first installation. If for testing purposes you only want to deploy or upgrade the nodes but avoiding the creation of the cluster you can set cluster.init to false.

Adding a new node to the cluster

There is a job that will be executed using a post-upgrade hook that will allow you to add a new node. To use it, you should provide some parameters to the upgrade:

• Pass as password the password used in the installation time. If you did not provide a password follow the instructions from the NOTES.txt to get the generated password.
• Set the desired number of nodes at cluster.nodes.
• Set the number of current nodes at cluster.update.currentNumberOfNodes.
• Set to true cluster.update.addNodes.

The following will be an example to add one more node:

helm upgrade --timeout 600s <release> --set "password=${REDIS_PASSWORD},cluster.nodes=7,cluster.update.addNodes=true,cluster.update.currentNumberOfNodes=6" oci://registry-1.docker.io/bitnamicharts/redis-cluster

Where REDIS_PASSWORD is the password obtained with the command that appears after the first installation of the Helm Chart. The cluster will continue up while restarting pods one by one as the quorum is not lost.

External Access

If you are using external access, to add a new node you will need to perform two upgrades. First upgrade the release to add a new Redis® node and to get a LoadBalancerIP service. For example:

helm upgrade <release> --set "password=${REDIS_PASSWORD},cluster.externalAccess.enabled=true,cluster.externalAccess.service.type=LoadBalancer,cluster.externalAccess.service.loadBalancerIP[0]=<loadBalancerip-0>,cluster.externalAccess.service.loadBalancerIP[1]=<loadbalanacerip-1>,cluster.externalAccess.service.loadBalancerIP[2]=<loadbalancerip-2>,cluster.externalAccess.service.loadBalancerIP[3]=<loadbalancerip-3>,cluster.externalAccess.service.loadBalancerIP[4]=<loadbalancerip-4>,cluster.externalAccess.service.loadBalancerIP[5]=<loadbalancerip-5>,cluster.externalAccess.service.loadBalancerIP[6]=,cluster.nodes=7,cluster.init=false oci://registry-1.docker.io/bitnamicharts/redis-cluster

Important here to provide the loadBalancerIP parameters for the new nodes empty to not get an index error.

As we want to add a new node, we are setting cluster.nodes=7 and we leave empty the LoadBalancerIP for the new node, so the cluster will provide the correct one. REDIS_PASSWORD is the password obtained with the command that appears after the first installation of the Helm Chart. At this point, you will have a new Redis® Pod that will remain in crashLoopBackOff state until we provide the LoadBalancerIP for the new service. Now, wait until the cluster provides the new LoadBalancerIP for the new service and perform the second upgrade:

helm upgrade <release> --set "password=${REDIS_PASSWORD},cluster.externalAccess.enabled=true,cluster.externalAccess.service.type=LoadBalancer,cluster.externalAccess.service.loadBalancerIP[0]=<loadbalancerip-0>,cluster.externalAccess.service.loadBalancerIP[1]=<loadbalancerip-1>,cluster.externalAccess.service.loadBalancerIP[2]=<loadbalancerip-2>,cluster.externalAccess.service.loadBalancerIP[3]=<loadbalancerip-3>,cluster.externalAccess.service.loadBalancerIP[4]=<loadbalancerip-4>,cluster.externalAccess.service.loadBalancerIP[5]=<loadbalancerip-5>,cluster.externalAccess.service.loadBalancerIP[6]=<loadbalancerip-6>,cluster.nodes=7,cluster.init=false,cluster.update.addNodes=true,cluster.update.newExternalIPs[0]=<load-balancerip-6>" oci://registry-1.docker.io/bitnamicharts/redis-cluster

Note we are providing the new IPs at cluster.update.newExternalIPs, the flag cluster.update.addNodes=true to enable the creation of the Job that adds a new node and now we are setting the LoadBalancerIP of the new service instead of leave it empty.

NOTE: To avoid the creation of the Job that initializes the Redis® Cluster again, you will need to provide cluster.init=false.

Scale down the cluster

To scale down the Redis® Cluster, follow these steps:

First perform a normal upgrade setting the cluster.nodes value to the desired number of nodes. It should not be less than 6 and the difference between current number of nodes and the desired should be less or equal to cluster.replicas to avoid removing master node an its slaves at the same time. Also it is needed to provide the password using the password. For example, having more than 6 nodes, to scale down the cluster to 6 nodes:

helm upgrade --timeout 600s <release> --set "password=${REDIS_PASSWORD},cluster.nodes=6" .

The cluster will continue working during the update as long as the quorum is not lost.

NOTE: To avoid the creation of the Job that initializes the Redis® Cluster again, you will need to provide cluster.init=false.

Once all the nodes are ready, get the list of nodes in the cluster using the CLUSTER NODES command. You will see references to the ones that were removed. Write down the node IDs of the nodes that show fail. In the following example the cluster scaled down from 7 to 6 nodes.

redis-cli -a $REDIS_PASSWORD CLUSTER NODES

...
b23bcffa1fd64368d445c1d9bd9aeb92641105f7 10.0.0.70:6379@16379 slave,fail - 1645633139060 0 0 connected
...

In each cluster node, execute the following command. Replace the NODE_ID placeholder.

redis-cli -a $REDIS_PASSWORD CLUSTER FORGET NODE_ID

In the previous example the commands would look like this in each cluster node:

redis-cli -a $REDIS_PASSWORD CLUSTER FORGET b23bcffa1fd64368d445c1d9bd9aeb92641105f7

Using password file

To use a password file for Redis® you need to create a secret containing the password.

NOTE: It is important that the file with the password must be called redis-password

And then deploy the Helm Chart using the secret name as parameter:

usePassword=true
usePasswordFile=true
existingSecret=redis-password-secret
metrics.enabled=true

Securing traffic using TLS

TLS support can be enabled in the chart by specifying the tls. parameters while creating a release. The following parameters should be configured to properly enable the TLS support in the cluster:

• tls.enabled: Enable TLS support. Defaults to false
• tls.existingSecret: Name of the secret that contains the certificates. No defaults.
• tls.certFilename: Certificate filename. No defaults.
• tls.certKeyFilename: Certificate key filename. No defaults.
• tls.certCAFilename: CA Certificate filename. No defaults.

For example:

First, create the secret with the certificates files:

kubectl create secret generic certificates-tls-secret --from-file=./cert.pem --from-file=./cert.key --from-file=./ca.pem

Then, use the following parameters:

tls.enabled="true"
tls.existingSecret="certificates-tls-secret"
tls.certFilename="cert.pem"
tls.certKeyFilename="cert.key"
tls.certCAFilename="ca.pem"

Sidecars and Init Containers

If you have a need for additional containers to run within the same pod as Redis® (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

Adding extra environment variables

In case you want to add extra environment variables (useful for advanced operations like custom init scripts), you can use the extraEnvVars property.

extraEnvVars:
  - name: REDIS_WHATEVER
    value: value

Alternatively, you can use a ConfigMap or a Secret with the environment variables. To do so, use the extraEnvVarsCM or the extraEnvVarsSecret values.

Metrics

The chart optionally can start a metrics exporter for prometheus. The metrics endpoint (port 9121) is exposed in the service. Metrics can be scraped from within the cluster using something similar as the described in the example Prometheus scrape configuration. If metrics are to be scraped from outside the cluster, the Kubernetes API proxy can be utilized to access the endpoint.

Host Kernel Settings

Redis® may require some changes in the kernel of the host machine to work as expected, in particular increasing the somaxconn value and disabling transparent huge pages. To do so, you can set up a privileged initContainer with the sysctlImage config values, for example:

sysctlImage:
  enabled: true
  mountHostSys: true
  command:
    - /bin/sh
    - -c
    - |-
      sysctl -w net.core.somaxconn=10000
      echo never > /host-sys/kernel/mm/transparent_hugepage/enabled

Alternatively, for Kubernetes 1.12+ you can set podSecurityContext.sysctls which will configure sysctls for master and slave pods. Example:

podSecurityContext:
  sysctls:
  - name: net.core.somaxconn
    value: "10000"

Note that this will not disable transparent huge tables.

Helm Upgrade

By default cluster.init will be set to true in order to initialize the Redis® Cluster in the first installation. If for testing purposes you only want to deploy or upgrade the nodes but avoiding the creation of the cluster you can set cluster.init to false.

Persistence

By default, the chart mounts a Persistent Volume at the /bitnami path. The volume is created using dynamic volume provisioning.

If persistence is disabled, an emptyDir volume is used. This is only recommended for testing environments because the required information included in the nodes.conf file is missing. This file contains the relationship between the nodes and the cluster. For example, if any node is down or faulty, when it starts again, it is a self-proclaimed master and also acts as an independent node outside the main cluster as it doesn't have the necessary information to connect to it.

To reconnect the failed node, run the following:

See nodes.sh

$ cat /bitnami/redis/data/nodes.sh
declare -A host_2_ip_array=([redis-node-0]="192.168.192.6" [redis-node-1]="192.168.192.2" [redis-node-2]="192.168.192.4" [redis-node-3]="192.168.192.5" [redis-node-4]="192.168.192.3" [redis-node-5]="192.168.192.7" )

Run redis-cli and run CLUSTER MEET to any other node in the cluster. Now the node has connected to the main cluster.

$ REDISCLI_AUTH=bitnami redis-cli
127.0.0.1:6379> cluster meet 192.168.192.7 6379
OK

See #15075

NetworkPolicy

To enable network policy for Redis®, install a networking plugin that implements the Kubernetes NetworkPolicy spec, and set networkPolicy.enabled to true.

For Kubernetes v1.5 & v1.6, you must also turn on NetworkPolicy by setting the DefaultDeny namespace annotation. Note: this will enforce policy for all pods in the namespace:

kubectl annotate namespace default "net.beta.kubernetes.io/network-policy={\"ingress\":{\"isolation\":\"DefaultDeny\"}}"

With NetworkPolicy enabled, only pods with the generated client label will be able to connect to Redis®. This label will be displayed in the output after a successful install.

With networkPolicy.ingressNSMatchLabels pods from other namespaces can connect to redis. Set networkPolicy.ingressNSPodMatchLabels to match pod labels in matched namespace. For example, for a namespace labeled redis=external and pods in that namespace labeled redis-client=true the fields should be set:

networkPolicy:
  enabled: true
  ingressNSMatchLabels:
    redis: external
  ingressNSPodMatchLabels:
    redis-client: true

Setting Pod's affinity

This chart allows you to set your custom affinity using the XXX.affinity paremeter(s). Find more information about Pod's affinity in the kubernetes documentation.

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

Troubleshooting

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

Upgrading

To 7.0.0

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.

Since this version performs changes in the statefulset, in order to upgrade from previous versions you need to delete the statefulset object before the upgrade.

kubectl delete statefulset <statefulsetName>
helm upgrade <release-name>  oci://registry-1.docker.io/bitnamicharts/redis-cluster --set redis.password=<REDIS_PASSWORD>

To 6.0.0

The cluster initialization job have been removed. Instead, the pod with index 0 from the statefulset will handle the initialization of the cluster.

As consequence, the initJob configuration section have been removed.

To 5.0.0

This major version updates the Redis® docker image version used from 6.0 to 6.2, the new stable version. There are no major changes in the chart and there shouldn't be any breaking changes in it as 6.2 breaking changes center around some command and behaviour changes. For more information, please refer to Redis® 6.2 release notes.

To 4.0.0

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/

To 3.0.0

This version of the chart adapts the chart to the most recent Bitnami best practices and standards. Most of the Redis® parameters were moved to the redis values section (such as extraEnvVars, sidecars, and so on). No major issues are expected during the upgrade.

To 2.0.0

The version 1.0.0 was using a label in the Statefulset's volumeClaimTemplate that didn't allow to upgrade the chart. The version 2.0.0 fixed that issue. Also it adds more docs in the README.md.

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.