The following article reviews the mechanism and methods available for sizing and scaling a Redis Enterprise cluster deployment.

For minimum and recommended sizing, always follow the sizing guidelines detailed in the Redis Enterprise hardware requirements.

Sizing and scaling cluster nodes

Setting the number of cluster nodes

Define the number of cluster nodes in redis-enterprise-cluster.yaml file.

spec:

    nodes: 3

The number of nodes in the cluster must be an uneven number equal to or greater than 3. Refer to the article Highly Available Redis for a detailed explanation on this topic.

Set the number of cluster nodes during deployment by editing the redis-enterprise-cluster.yaml file and applying the file by running:

kubectl apply -f redis-enterprise-cluster.yaml

Scaling out

To scale out a Redis Enterprise Cluster deployment, increase the number of nodes in the spec. For example, to scale the cluster out from 3 nodes to 5 nodes, edit the redis-enterprise-cluster.yaml file with the following:

spec:

    nodes: 5

To apply the new cluster configuration run:

kubectl apply -f redis-enterprise-cluster.yaml

Note: Decreasing the number of nodes is not supported.

Sizing compute resources

To set the compute resources required for each node, use the redisEnterpriseNodeResources spec field.

Under redisEnterpriseNodeResources spec, set the following fields according to the provided guidelines.

  • limits – specifies the maximum compute resources for a Redis node
  • requests – specifies the minimum compute resources for a Redis node

For example:

redisEnterpriseNodeResources:

    limits:

    cpu: “2000m”

    memory: 4Gi

    requests:

    cpu: “2000m”

    memory: 4Gi

The default values, if unspecified, are 2 cores (2000m) and 4GB (4Gi).

Set the compute resources for cluster nodes during deployment by editing the redis-enterprise-cluster.yaml file and applying the file by running:

kubectl apply -f redis-enterprise-cluster.yaml

Scaling up node compute resources

To scale up nodes in an existing Redis Enterprise Cluster deployment, adjust the cpu and memory parameters in the spec. For example, to scale nodes up to the recommended amount of compute resources, edit the redis-enterprise-cluster.yaml file with the following:

redisEnterpriseNodeResources:

limits:

    cpu: “8000m”

    memory: 30Gi

requests

    cpu: “8000m”

    memory: 30Gi

Then, apply the file by running:

kubectl apply -f redis-enterprise-cluster.yaml
Warning -
Be aware that persistent volume size cannot be changed after deployment. When adjusting compute resources, make sure the ratio of persistent volume size and the new memory size are in accordance to the Hardware requirements.