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[stable/redis] Unify and refactor README.md (#18293)

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Signed-off-by: Carlos Rodriguez Hernandez <crhernandez@bitnami.com>
This commit is contained in:
Carlos Rodríguez Hernández
2019-10-24 08:43:19 -07:00
committed by Kubernetes Prow Robot
parent bffe90bfbf
commit ff335984e4
2 changed files with 129 additions and 130 deletions
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stable/redis/Chart.yaml
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@@ -1,6 +1,6 @@
apiVersion: v1
name: redis
version: 9.4.1
version: 9.4.2
appVersion: 5.0.5
description: 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.
keywords:
stable/redis/README.md
+128 -129
View File
@@ -35,7 +35,7 @@ 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](#configuration) section lists the parameters that can be configured during installation.
The command deploys Redis on the Kubernetes cluster in the default configuration. The [Parameters](#parameters) section lists the parameters that can be configured during installation.
> **Tip**: List all releases using `helm list`
@@ -49,77 +49,7 @@ $ helm delete my-release
The command removes all the Kubernetes components associated with the chart and deletes the release.
## Upgrading an existing Release to a new major version
A major chart version change (like v1.2.3 -> v2.0.0) indicates that there is an
incompatible breaking change needing manual actions.
### 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](https://github.com/oliver006/redis_exporter/blob/master/contrib/grafana_prometheus_redis_dashboard.json) now. Please see the [redis_exporter github page](https://github.com/oliver006/redis_exporter#upgrading-from-0x-to-1x) 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](https://github.com/edseymour/pvc-transfer)). Then launch a fresh release reusing this cloned PVC.
```
helm install stable/redis --set persistence.existingClaim=<NEW PVC>
```
- 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 <RELEASE>
helm install stable/redis --name <RELEASE>
```
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`.
### 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:
```bash
$ kubectl delete statefulsets.apps --cascade=false my-release-redis-master
```
And edit the Redis slave (and metrics if enabled) deployment:
```bash
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"}]'
```
## Configuration
## Parameters
The following table lists the configurable parameters of the Redis chart and their default values.
@@ -322,27 +252,17 @@ $ helm install --name my-release -f values.yaml stable/redis
> **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. Consider installing Redis with `--set persistence.enabled=false`. See minikube issue [1990](https://github.com/kubernetes/minikube/issues/1990) for more information.
### Using password file
To use a password file for Redis you need to create a secret containing the password:
## Configuration and installation details
```bash
$ kubectl create secret generic redis-password-file --from-file=/tmp/redis-password
```
> *NOTE*: It is important that the file with the password must be called `redis-password`
### [Rolling VS Immutable tags](https://docs.bitnami.com/containers/how-to/understand-rolling-tags-containers/)
And deploy the Helm Chart using the secret name:
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.
```bash
$ helm install stable/redis --set usePassword=true,usePasswordFile=true,existingSecret=redis-password-file,sentinels.enabled=true,metrics.enabled=true
```
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`.
```console
$ helm install --name my-release -f ./values-production.yaml stable/redis
```
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 slaves:
```diff
@@ -362,46 +282,52 @@ $ helm install --name my-release -f ./values-production.yaml stable/redis
+ metrics.enabled: true
```
### [Rolling VS Immutable tags](https://docs.bitnami.com/containers/how-to/understand-rolling-tags-containers/)
### Cluster topologies
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.
#### Default: Master-Slave
Bitnami will release a new chart updating its containers if a new version of the main container, significant changes, or critical vulnerabilities exist.
When installing the chart with `cluster.enabled=true`, it will deploy a Redis master StatefulSet (only one master node allowed) and a Redis slave StatefulSet. The slaves will be read-replicas of the master. Two services will be exposed:
## NetworkPolicy
- Redis Master service: Points to the master, where read-write operations can be performed
- Redis Slave service: Points to the slaves, where only read operations are allowed.
To enable network policy for Redis, install
[a networking plugin that implements the Kubernetes NetworkPolicy spec](https://kubernetes.io/docs/tasks/administer-cluster/declare-network-policy#before-you-begin),
and set `networkPolicy.enabled` to `true`.
In case the master crashes, the slaves will wait until the master node is respawned again by the Kubernetes Controller Manager.
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:
#### Master-Slave with Sentinel
kubectl annotate namespace default "net.beta.kubernetes.io/network-policy={\"ingress\":{\"isolation\":\"DefaultDeny\"}}"
When installing the chart with `cluster.enabled=true` and `sentinel.enabled=true`, it will deploy a Redis master StatefulSet (only one master allowed) and a Redis slave StatefulSet. In this case, the pods will contain en 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. In addition to this, only one service is exposed:
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.
- Redis service: Exposes port 6379 for Redis read-only operations and port 26379 for accesing Redis Sentinel.
## Persistence
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:
By default, the chart mounts a [Persistent Volume](http://kubernetes.io/docs/user-guide/persistent-volumes/) at the `/data` path. The volume is created using dynamic volume provisioning. If a Persistent Volume Claim already exists, specify it during installation.
```
SENTINEL get-master-addr-by-name <name of your MasterSet. Example: mymaster>
```
This command will return the address of the current master, which can be accessed from inside the cluster.
### Existing PersistentVolumeClaim
In case the current master crashes, the Sentinel containers will elect a new master node.
1. Create the PersistentVolume
2. Create the PersistentVolumeClaim
3. Install the chart
### Using password file
To use a password file for Redis you need to create a secret containing the password.
```bash
$ helm install --set persistence.existingClaim=PVC_NAME stable/redis
> *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:
```console
usePassword=true
usePasswordFile=true
existingSecret=redis-password-file
sentinels.enabled=true
metrics.enabled=true
```
## Metrics
### Metrics
The chart optionally can start a metrics exporter for [prometheus](https://prometheus.io). 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](https://github.com/prometheus/prometheus/blob/master/documentation/examples/prometheus-kubernetes.yml). If metrics are to be scraped from outside the cluster, the Kubernetes API proxy can be utilized to access the endpoint.
## Host Kernel Settings
### 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:
```
@@ -428,31 +354,104 @@ securityContext:
Note that this will not disable transparent huge tables.
## Cluster topologies
## Persistence
### Default: Master-Slave
By default, the chart mounts a [Persistent Volume](http://kubernetes.io/docs/user-guide/persistent-volumes/) at the `/data` path. The volume is created using dynamic volume provisioning. If a Persistent Volume Claim already exists, specify it during installation.
When installing the chart with `cluster.enabled=true`, it will deploy a Redis master StatefulSet (only one master node allowed) and a Redis slave StatefulSet. The slaves will be read-replicas of the master. Two services will be exposed:
### Existing PersistentVolumeClaim
- Redis Master service: Points to the master, where read-write operations can be performed
- Redis Slave service: Points to the slaves, where only read operations are allowed.
In case the master crashes, the slaves will wait until the master node is respawned again by the Kubernetes Controller Manager.
### Master-Slave with Sentinel
When installing the chart with `cluster.enabled=true` and `sentinel.enabled=true`, it will deploy a Redis master StatefulSet (only one master allowed) and a Redis slave StatefulSet. In this case, the pods will contain en 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. In addition to this, only one service is exposed:
- Redis service: Exposes port 6379 for Redis read-only operations and port 26379 for accesing 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:
1. Create the PersistentVolume
2. Create the PersistentVolumeClaim
3. Install the chart
```bash
$ helm install --set persistence.existingClaim=PVC_NAME stable/redis
```
SENTINEL get-master-addr-by-name <name of your MasterSet. Example: 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.
## NetworkPolicy
To enable network policy for Redis, install
[a networking plugin that implements the Kubernetes NetworkPolicy spec](https://kubernetes.io/docs/tasks/administer-cluster/declare-network-policy#before-you-begin),
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.
## Upgrading an existing Release to a new major version
A major chart version change (like v1.2.3 -> v2.0.0) indicates that there is an
incompatible breaking change needing manual actions.
### 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](https://github.com/oliver006/redis_exporter/blob/master/contrib/grafana_prometheus_redis_dashboard.json) now. Please see the [redis_exporter github page](https://github.com/oliver006/redis_exporter#upgrading-from-0x-to-1x) 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](https://github.com/edseymour/pvc-transfer)). Then launch a fresh release reusing this cloned PVC.
```
helm install stable/redis --set persistence.existingClaim=<NEW PVC>
```
- 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 <RELEASE>
helm install stable/redis --name <RELEASE>
```
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`.
### 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:
```bash
$ kubectl delete statefulsets.apps --cascade=false my-release-redis-master
```
And edit the Redis slave (and metrics if enabled) deployment:
```bash
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"}]'
```
## Notable changes