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RedisAutoscaler

What is RedisAutoscaler

RedisAutoscaler is a Kubernetes Custom Resource Definitions (CRD). It provides a declarative configuration for autoscaling Redis compute resources and storage of database components in a Kubernetes native way.

RedisAutoscaler CRD Specifications

Like any official Kubernetes resource, a RedisAutoscaler has TypeMeta, ObjectMeta, Spec and Status sections.

Here is a sample RedisAutoscaler CRO for autoscaling different components of database is given below:

Sample RedisAutoscaler for standalone database:

apiVersion: autoscaling.kubedb.com/v1alpha1
kind: RedisAutoscaler
metadata:
  name: standalone-autoscaler
  namespace: demo
spec:
  databaseRef:
    name: redis-standalone
  opsRequestOptions:
    apply: IfReady
    timeout: 5m
  compute:
    standalone: 
      trigger: "On"
      podLifeTimeThreshold: 5m
      minAllowed:
        cpu: 600m
        memory: 600Mi
      maxAllowed:
        cpu: 1
        memory: 1Gi
      controlledResources: ["cpu", "memory"]
      containerControlledValues: "RequestsAndLimits"
      resourceDiffPercentage: 10
  storage:
    standalone:
      expansionMode: "Online"
      trigger: "On"
      usageThreshold: 25
      scalingThreshold: 20

Here is a sample RedisSentinelAutoscaler CRO for autoscaling different components of database is given below:

Sample RedisSentinelAutoscaler for standalone database:

apiVersion: autoscaling.kubedb.com/v1alpha1
kind: RedisSentinelAutoscaler
metadata:
  name: sentinel-autoscalar
  namespace: demo
spec:
  databaseRef:
    name: sentinel
  opsRequestOptions:
    apply: IfReady
    timeout: 5m
  compute:
    sentinel: 
      trigger: "On"
      podLifeTimeThreshold: 5m
      minAllowed:
        cpu: 600m
        memory: 600Mi
      maxAllowed:
        cpu: 1
        memory: 1Gi
      controlledResources: ["cpu", "memory"]
      containerControlledValues: "RequestsAndLimits"
      resourceDiffPercentage: 10

Here, we are going to describe the various sections of a RedisAutoscaler and RedisSentinelAutoscaler crd.

A RedisAutoscaler object has the following fields in the spec section.

spec.databaseRef

spec.databaseRef is a required field that point to the Redis object for which the autoscaling will be performed. This field consists of the following sub-field:

• spec.databaseRef.name : specifies the name of the Redis object.

spec.opsRequestOptions

These are the options to pass in the internally created opsRequest CRO. opsRequestOptions has three fields. They have been described in details here.

spec.compute

spec.compute specifies the autoscaling configuration for to compute resources i.e. cpu and memory of the database components. This field consists of the following sub-field:

• spec.compute.standalone indicates the desired compute autoscaling configuration for a standalone mode in Redis database.
• spec.compute.cluster indicates the desired compute autoscaling configuration for cluster mode in Redis database.
• spec.compute.sentinel indicates the desired compute autoscaling configuration for sentinel mode in Redis database.

RedisSentinelAutoscaler on has only spec.compute.sentinel field.

All of them has the following sub-fields:

• trigger indicates if compute autoscaling is enabled for this component of the database. If “On” then compute autoscaling is enabled. If “Off” then compute autoscaling is disabled.
• minAllowed specifies the minimal amount of resources that will be recommended, default is no minimum.
• maxAllowed specifies the maximum amount of resources that will be recommended, default is no maximum.
• controlledResources specifies which type of compute resources (cpu and memory) are allowed for autoscaling. Allowed values are “cpu” and “memory”.
• containerControlledValues specifies which resource values should be controlled. Allowed values are “RequestsAndLimits” and “RequestsOnly”.
• resourceDiffPercentage specifies the minimum resource difference between recommended value and the current value in percentage. If the difference percentage is greater than this value than autoscaling will be triggered.
• podLifeTimeThreshold specifies the minimum pod lifetime of at least one of the pods before triggering autoscaling.

spec.storage

spec.storage specifies the autoscaling configuration for the storage resources of the database components. This field consists of the following sub-field:

• spec.storage.standalone indicates the desired storage autoscaling configuration for a standalone mode in Redis database.
• spec.storage.cluster indicates the desired storage autoscaling configuration for cluster mode in Redis database.
• spec.storage.sentinel indicates the desired storage autoscaling configuration for sentinel mode in Redis database.

RedisSentinelAutoscaler does not have spec.storage section.

All of them has the following sub-fields:

• trigger indicates if storage autoscaling is enabled for this component of the database. If “On” then storage autoscaling is enabled. If “Off” then storage autoscaling is disabled.
• usageThreshold indicates usage percentage threshold, if the current storage usage exceeds then storage autoscaling will be triggered.
• scalingThreshold indicates the percentage of the current storage that will be scaled.
• expansionMode indicates the volume expansion mode.

Next Steps

• Learn about Redis crd here.
• Deploy your first Redis database with Redis by following the guide here.