Bitnami package for Redis(R)

Redis(R) is an open source, advanced key-value store. It is often referred to as a data structure server since keys can contain strings, hashes, lists, sets and sorted sets.

Overview of Redis®

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

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.

1. Redis® Helm Chart will deploy a master-replica cluster, with the option of enabling using Redis® Sentinel.
2. Redis® Cluster Helm Chart will deploy a Redis® Cluster topology 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)

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

The command deploys Redis® 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

Global parameters

Common parameters

Redis® Image parameters

Redis® common configuration parameters

Redis® master configuration parameters

Redis® replicas configuration parameters

Redis® Sentinel configuration parameters

Other Parameters

Metrics Parameters

Init Container Parameters

useExternalDNS Parameters

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

$ helm install my-release \
  --set auth.password=secretpassword \
    my-repo/redis

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 my-repo/redis

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.

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.

Bootstrapping with an External Cluster

This chart is equipped with the ability to bring online a set of Pods that connect to an existing Redis deployment that lies outside of Kubernetes. This effectively creates a hybrid Redis Deployment where both Pods in Kubernetes and Instances such as Virtual Machines can partake in a single Redis Deployment. This is helpful in situations where one may be migrating Redis from Virtual Machines into Kubernetes, for example. To take advantage of this, use the following as an example configuration:

replica:
  externalMaster:
    enabled: true
    host: external-redis-0.internal
sentinel:
  externalMaster:
    enabled: true
    host: external-redis-0.internal

:warning: This is currently limited to clusters in which Sentinel and Redis run on the same node! :warning:

Please also note that the external sentinel must be listening on port 26379, and this is currently not configurable.

Once the Kubernetes Redis Deployment is online and confirmed to be working with the existing cluster, the configuration can then be removed and the cluster will remain connected.

External DNS

This chart is equipped to allow leveraging the ExternalDNS project. Doing so will enable ExternalDNS to publish the FQDN for each instance, in the format of <pod-name>.<release-name>.<dns-suffix>. Example, when using the following configuration:

useExternalDNS:
  enabled: true
  suffix: prod.example.org
  additionalAnnotations:
    ttl: 10

On a cluster where the name of the Helm release is a, the hostname of a Pod is generated as: a-redis-node-0.a-redis.prod.example.org. The IP of that FQDN will match that of the associated Pod. This modifies the following parameters of the Redis/Sentinel configuration using this new FQDN:

• replica-announce-ip
• known-sentinel
• known-replica
• announce-ip

:warning: This requires a working installation of external-dns to be fully functional. :warning:

See the official ExternalDNS documentation for additional configuration options.

Cluster topologies

Default: Master-Replicas

When installing the chart with architecture=replication, it will deploy a Redis® master StatefulSet and a Redis® replicas StatefulSet. The replicas will be read-replicas of the master. Two services will be exposed:

• Redis® Master service: Points to the master, where read-write operations can be performed
• Redis® Replicas service: Points to the replicas, where only read operations are allowed by default.

In case the master crashes, the replicas will wait until the master node is respawned again by the Kubernetes Controller Manager.

Standalone

When installing the chart with architecture=standalone, it will deploy a standalone Redis® StatefulSet. A single service will be exposed:

• Redis® Master service: Points to the master, where read-write operations can be performed

Master-Replicas with Sentinel

When installing the chart with architecture=replication and sentinel.enabled=true, it will deploy a Redis® master StatefulSet (only one master allowed) and a Redis® replicas StatefulSet. In this case, the pods will contain an extra container with Redis® Sentinel. This container will form a cluster of Redis® Sentinel nodes, which will promote a new master in case the actual one fails.

On graceful termination of the Redis® master pod, a failover of the master is initiated to promote a new master. The Redis® Sentinel container in this pod will wait for the failover to occur before terminating. If sentinel.redisShutdownWaitFailover=true is set (the default), the Redis® container will wait for the failover as well before terminating. This increases availability for reads during failover, but may cause stale reads until all clients have switched to the new master.

In addition to this, only one service is exposed:

• Redis® service: Exposes port 6379 for Redis® read-only operations and port 26379 for accessing Redis® Sentinel.

For read-only operations, access the service using port 6379. For write operations, it's necessary to access the Redis® Sentinel cluster and query the current master using the command below (using redis-cli or similar):

SENTINEL get-master-addr-by-name <name of your MasterSet. e.g: mymaster>

This command will return the address of the current master, which can be accessed from inside the cluster.

In case the current master crashes, the Sentinel containers will elect a new master node.

master.count greater than 1 is not designed for use when sentinel.enabled=true.

Multiple masters (experimental)

When master.count is greater than 1, special care must be taken to create a consistent setup.

An example of use case is the creation of a redundant set of standalone masters or master-replicas per Kubernetes node where you must ensure:

• No more than 1 master can be deployed per Kubernetes node
• Replicas and writers can only see the single master of their own Kubernetes node

One way of achieving this is by setting master.service.internalTrafficPolicy=Local in combination with a master.affinity.podAntiAffinity spec to never schedule more than one master per Kubernetes node.

It's recommended to only change master.count if you know what you are doing. master.count greater than 1 is not designed for use when sentinel.enabled=true.

Using a password file

To use a password file for Redis® you need to create a secret containing the password and then deploy the chart using that secret.

Refer to the chart documentation for more information on using a password file for Redis®.

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 chart:

• 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.

Refer to the chart documentation for more information on creating the secret and a TLS deployment example.

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.

If you have enabled TLS by specifying tls.enabled=true you also need to specify TLS option to the metrics exporter. You can do that via metrics.extraArgs. You can find the metrics exporter CLI flags for TLS here. For example:

You can either specify metrics.extraArgs.skip-tls-verification=true to skip TLS verification or providing the following values under metrics.extraArgs for TLS client authentication:

tls-client-key-file
tls-client-cert-file
tls-ca-cert-file

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.

Refer to the chart documentation for more information on configuring host kernel settings with an example.

Persistence

By default, the chart mounts a Persistent Volume at the /data path. 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 my-release --set master.persistence.existingClaim=PVC_NAME my-repo/redis

Backup and restore

Refer to the chart documentation for more information on backing up and restoring Redis® deployments.

NetworkPolicy

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

Refer to the chart documenation for more information on enabling the network policy in Redis® deployments.

Setting Pod's affinity

This chart allows you to set your custom affinity using the XXX.affinity parameter(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

A major chart version change (like v1.2.3 -> v2.0.0) indicates that there is an incompatible breaking change needing manual actions.

To 17.0.0

This major version updates the Redis® docker image version used from 6.2 to 7.0, the new stable version. There are no major changes in the chart, but we recommend checking the Redis® 7.0 release notes before upgrading.

To 16.0.0

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:

• master.service.port renamed as master.service.ports.redis.
• master.service.nodePort renamed as master.service.nodePorts.redis.
• replica.service.port renamed as replica.service.ports.redis.
• replica.service.nodePort renamed as replica.service.nodePorts.redis.
• sentinel.service.port renamed as sentinel.service.ports.redis.
• sentinel.service.sentinelPort renamed as sentinel.service.ports.sentinel.
• master.containerPort renamed as master.containerPorts.redis.
• replica.containerPort renamed as replica.containerPorts.redis.
• sentinel.containerPort renamed as sentinel.containerPorts.sentinel.
• master.spreadConstraints renamed as master.topologySpreadConstraints
• replica.spreadConstraints renamed as replica.topologySpreadConstraints

To 15.0.0

The parameter to enable the usage of StaticIDs was removed. The behavior is to always use StaticIDs.

To 14.8.0

The Redis® sentinel exporter was removed in this version because the upstream project was deprecated. The regular Redis® exporter is included in the sentinel scenario as usual.

To 14.0.0

• Several parameters were renamed or disappeared in favor of new ones on this major version:
  • The term slave has been replaced by the term replica. Therefore, parameters prefixed with slave are now prefixed with replicas.
  • Credentials parameter are reorganized under the auth parameter.
  • cluster.enabled parameter is deprecated in favor of architecture parameter that accepts two values: standalone and replication.
  • securityContext.* is deprecated in favor of XXX.podSecurityContext and XXX.containerSecurityContext.
  • sentinel.metrics.* parameters are deprecated in favor of metrics.sentinel.* ones.
• New parameters to add custom command, environment variables, sidecars, init containers, etc. were added.
• Chart labels were adapted to follow the Helm charts standard labels.
• values.yaml metadata was adapted to follow the format supported by Readme Generator for Helm.

Consequences:

Backwards compatibility is not guaranteed. To upgrade to 14.0.0, install a new release of the Redis® chart, and migrate the data from your previous release. You have 2 alternatives to do so:

• Create a backup of the database, and restore it on the new release as explained in the Backup and restore section.
• Reuse the PVC used to hold the master data on your previous release. To do so, use the master.persistence.existingClaim parameter. The following example assumes that the release name is redis:

$ helm install redis my-repo/redis --set auth.password=[PASSWORD] --set master.persistence.existingClaim=[EXISTING_PVC]

| Note: you need to substitute the placeholder [EXISTING_PVC] with the name of the PVC used on your previous release, and [PASSWORD] with the password used in your previous release.

To 13.0.0

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 is basically a stricter superset of 6.0. For more information, please refer to Redis® 6.2 release notes.

To 12.3.0

This version also introduces bitnami/common, a library chart as a dependency. More documentation about this new utility could be found here. Please, make sure that you have updated the chart dependencies before executing any upgrade.

To 12.0.0

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.
• 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 11.0.0

When deployed with sentinel enabled, only a group of nodes is deployed and the master/slave role is handled in the group. To avoid breaking the compatibility, the settings for this nodes are given through the slave.xxxx parameters in values.yaml

To 9.0.0

The metrics exporter has been changed from a separate deployment to a sidecar container, due to the latest changes in the Redis® exporter code. Check the official page for more information. The metrics container image was changed from oliver006/redis_exporter to bitnami/redis-exporter (Bitnami's maintained package of oliver006/redis_exporter).

To 7.0.0

In order to improve the performance in case of slave failure, we added persistence to the read-only slaves. That means that we moved from Deployment to StatefulSets. This should not affect upgrades from previous versions of the chart, as the deployments did not contain any persistence at all.

This version also allows enabling Redis® Sentinel containers inside of the Redis® Pods (feature disabled by default). In case the master crashes, a new Redis® node will be elected as master. In order to query the current master (no redis master service is exposed), you need to query first the Sentinel cluster.

To 11.0.0

When using sentinel, a new statefulset called -node was introduced. This will break upgrading from a previous version where the statefulsets are called master and slave. Hence the PVC will not match the new naming and won't be reused. If you want to keep your data, you will need to perform a backup and then a restore the data in this new version.

To 10.0.0

For releases with usePassword: true, the value sentinel.usePassword controls whether the password authentication also applies to the sentinel port. This defaults to true for a secure configuration, however it is possible to disable to account for the following cases:

• Using a version of redis-sentinel prior to 5.0.1 where the authentication feature was introduced.
• Where redis clients need to be updated to support sentinel authentication.

If using a master/slave topology, or with usePassword: false, no action is required.

To 8.0.18

For releases with metrics.enabled: true the default tag for the exporter image is now v1.x.x. This introduces many changes including metrics names. You'll want to use this dashboard now. Please see the redis_exporter github page for more details.

To 7.0.0

This version causes a change in the Redis® Master StatefulSet definition, so the command helm upgrade would not work out of the box. As an alternative, one of the following could be done:

• Recommended: Create a clone of the Redis® Master PVC (for example, using projects like this one). Then launch a fresh release reusing this cloned PVC.

$ helm install my-release my-repo/redis --set persistence.existingClaim=

- Alternative (not recommended, do at your own risk): `helm delete --purge` does not remove the PVC assigned to the Redis® Master StatefulSet. As a consequence, the following commands can be done to upgrade the release

$ helm delete --purge $ helm install my-repo/redis

Previous versions of the chart were not using persistence in the slaves, so this upgrade would add it to them. Another important change is that no values are inherited from master to slaves. For example, in 6.0.0 `slaves.readinessProbe.periodSeconds`, if empty, would be set to `master.readinessProbe.periodSeconds`. This approach lacked transparency and was difficult to maintain. From now on, all the slave parameters must be configured just as it is done with the masters.

Some values have changed as well:

- `master.port` and `slave.port` have been changed to `redisPort` (same value for both master and slaves)
- `master.securityContext` and `slave.securityContext` have been changed to `securityContext`(same values for both master and slaves)

By default, the upgrade will not change the cluster topology. In case you want to use Redis® Sentinel, you must explicitly set `sentinel.enabled` to `true`.

### To 6.0.0

Previous versions of the chart were using an init-container to change the permissions of the volumes. This was done in case the `securityContext` directive in the template was not enough for that (for example, with cephFS). In this new version of the chart, this container is disabled by default (which should not affect most of the deployments). If your installation still requires that init container, execute `helm upgrade` with the `--set volumePermissions.enabled=true`.

### To 5.0.0

The default image in this release may be switched out for any image containing the `redis-server`
and `redis-cli` binaries. If `redis-server` is not the default image ENTRYPOINT, `master.command`
must be specified.

#### Breaking changes

- `master.args` and `slave.args` are removed. Use `master.command` or `slave.command` instead in order to override the image entrypoint, or `master.extraFlags` to pass additional flags to `redis-server`.
- `disableCommands` is now interpreted as an array of strings instead of a string of comma separated values.
- `master.persistence.path` now defaults to `/data`.

### To 4.0.0

This version removes the `chart` label from the `spec.selector.matchLabels`
which is immutable since `StatefulSet apps/v1beta2`. It has been inadvertently
added, causing any subsequent upgrade to fail. See https://github.com/helm/charts/issues/7726.

It also fixes https://github.com/helm/charts/issues/7726 where a deployment `extensions/v1beta1` can not be upgraded if `spec.selector` is not explicitly set.

Finally, it fixes https://github.com/helm/charts/issues/7803 by removing mutable labels in `spec.VolumeClaimTemplate.metadata.labels` so that it is upgradable.

In order to upgrade, delete the Redis® StatefulSet before upgrading:

```console
$ kubectl delete statefulsets.apps --cascade=false my-release-redis-master

And edit the Redis® slave (and metrics if enabled) deployment:

$ kubectl patch deployments my-release-redis-slave --type=json -p='[{"op": "remove", "path": "/spec/selector/matchLabels/chart"}]'
$ kubectl patch deployments my-release-redis-metrics --type=json -p='[{"op": "remove", "path": "/spec/selector/matchLabels/chart"}]'

License

Copyright © 2022 Bitnami

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.