Managing autoscale policies

Autoscale policies automatically expand or shrink a cluster in your private cloud based on factors like CPU, memory, and storage utilization thresholds. According to the selected autoscale policy for a cluster, VMware Engine monitors the cluster based on the metrics defined and adds or removes nodes from the cluster automatically.

Predefined policies

Each cluster in your private cloud has an attached autoscale policy that measures utilization and consumption thresholds as a running average. When metrics specified in an autoscale policy are sustained for a period of 30 minutes, VMware Engine triggers an action based on the policy.

Because compute, memory, and storage usage are often independent, autoscale policies that monitor multiple metrics use OR logic for node addition and AND logic for node removal.

The following table describes predefined autoscale policies you can select for each cluster:

Autoscale policy Add node condition Remove node condition
Storage Capacity Optimization Policy (default) Storage consumed > 75% Storage consumed < 40%
CPU Performance Optimization Policy CPU utilization > 70% OR
Storage consumed > 75%
CPU utilization < 45% AND
Storage consumed < 40%
Memory Performance Optimization Policy Memory utilization > 80% OR
Storage consumed > 75%
Memory utilization < 45% AND
Storage consumed < 40%
CPU and Memory Performance Optimization Policy CPU utilization > 70% OR
Memory utilization > 80% OR
Storage consumed > 75%
CPU utilization < 45% AND
Memory utilization < 45% AND
Storage consumed < 40%

All clusters have a default autoscale policy called Storage capacity optimization policy that adjusts cluster size based on storage consumption. The default policy adds a node to the cluster when storage consumption exceeds 75% for 30 consecutive minutes. This helps ensure that your clusters meet the SLA requirement of having 25% free capacity.

Updating an autoscale policy

To view or change the autoscale policy associated with a cluster, do the following:

  1. Access the VMware Engine portal
  2. Go to Resources and select a private cloud.
  3. Go to Clusters and click the Edit icon.
  4. On the page that appears, you can view your current policy, select a new one from the Autoscale policy drop-down list, and optionally adjust policy details.
  5. Click Submit once you're finished.

The following list describes each field during policy creation in more detail:

  • Add nodes: Condition that must be met for a certain period of time before VMware Engine adds one or more nodes to the cluster.
  • Remove nodes: Condition that must be met for a certain period of time before VMware Engine removes a node from the cluster.
  • Cool off period: Minimum amount of time between actions taken due to an autoscale policy.
  • Node limits: Minimum and maximum number of nodes in a cluster between which an autoscale policy can adjust.