Redis

Redis is an advanced key-value cache and store. It is often referred to as a data structure server since keys can contain strings, hashes, lists, sets, sorted sets, bitmaps and hyperloglogs.

TL;DR;

$ helm install stable/redis

Introduction

This chart bootstraps a Redis deployment on a Kubernetes cluster using the Helm package manager.

Prerequisites

• Kubernetes 1.4+ with Beta APIs enabled
• PV provisioner support in the underlying infrastructure

Installing the Chart

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

$ helm install --name my-release stable/redis

The command deploys Redis on the Kubernetes cluster in the default configuration. The configuration 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.

Configuration

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

Parameter	Description	Default
image	Redis image	bitnami/redis:{VERSION}
imagePullPolicy	Image pull policy	IfNotPresent
serviceType	Kubernetes Service type	ClusterIP
usePassword	Use password	true
redisPassword	Redis password	Randomly generated
args	Redis command-line args	[]
persistence.enabled	Use a PVC to persist data	true
persistence.existingClaim	Use an existing PVC to persist data	nil
persistence.storageClass	Storage class of backing PVC	generic
persistence.accessMode	Use volume as ReadOnly or ReadWrite	ReadWriteOnce
persistence.size	Size of data volume	8Gi
resources	CPU/Memory resource requests/limits	Memory: 256Mi, CPU: 100m
metrics.enabled	Start a side-car prometheus exporter	false
metrics.image	Exporter image	oliver006/redis_exporter
metrics.imageTag	Exporter image	v0.11
metrics.imagePullPolicy	Exporter image pull policy	IfNotPresent
metrics.resources	Exporter resource requests/limit	Memory: 256Mi, CPU: 100m
nodeSelector	Node labels for pod assignment	{}
tolerations	Toleration labels for pod assignment	[]
networkPolicy.enabled	Enable NetworkPolicy	false
networkPolicy.allowExternal	Don't require client label for connections	true
service.annotations	annotations for redis service	{}
service.loadBalancerIP	loadBalancerIP if service type is LoadBalancer	``

The above parameters map to the env variables defined in bitnami/redis. For more information please refer to the bitnami/redis image documentation.

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

$ helm install --name my-release \
  --set redisPassword=secretpassword \
    stable/redis

The above command sets the Redis server password to secretpassword.

Alternatively, a YAML file that specifies the values for the parameters can be provided while installing the chart. For example,

$ helm install --name my-release -f values.yaml stable/redis

Tip: You can use the default values.yaml

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.

Persistence

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

By default, the chart mounts a Persistent Volume volume at this location. The volume is created using dynamic volume provisioning. If a Persistent Volume Claim already exists, specify it during installation.

Existing PersistentVolumeClaim

1. Create the PersistentVolume
2. Create the PersistentVolumeClaim
3. Install the chart

$ helm install --set persistence.existingClaim=PVC_NAME redis

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 Kubenretes API proxy can be utilized to access the endpoint.