CCE Advanced HPA

cce-hpa-controller is a CCE-developed add-on, which can be used to flexibly scale in or out Deployments based on metrics such as CPU usage and memory usage.

After installing this add-on, you can create CustomedHPA policies. For details, see CustomedHPA Policies.

Main Functions

Scaling can be performed based on the percentage of the current number of pods.
The minimum scaling step can be set.
Different scaling operations can be performed based on the actual metric values.

Constraints

This add-on can be installed only in clusters of v1.15 or later.
If the cce-hpa-controller version is earlier than 1.2.11, the Prometheus add-on must be installed. If the cce-hpa-controller version is 1.2.11 or later, the add-ons that can provide metrics API must be installed. Select one of the following add-ons based on your cluster version and actual requirements.
- Kubernetes Metrics Server: provides basic resource usage metrics, such as container CPU and memory usage. It is supported by all cluster versions.
- Prometheus: Prometheus needs to be registered as a metrics API. For details, see Providing Resource Metrics Through the Metrics API. This add-on supports only clusters of v1.21 or earlier.

Installing the Add-on

Log in to the CCE console and click the cluster name to access the cluster console. Click Add-ons in the navigation pane, locate CCE Advanced HPA on the right, and click Install.

On the Install Add-on page, configure the specifications.

**Table 1** cce-hpa-controller configuration
Parameter	Description
Add-on Specifications	Select Single or Custom for Add-on Specifications. NOTE: Single-instance add-ons are used only for service verification. In commercial deployments, select Custom based on the cluster specifications. The specifications of cce-hpa-controller are decided by the total number of containers in the cluster and the number of scaling policies. You are advised to configure 500m CPU and 1,000 MiB memory for every 5,000 containers, and 100m CPU and 500 MiB memory for every 1,000 scaling policies.
Instances	Number of pods that will be created to match the selected add-on specifications. If you select Custom, you can adjust the number of pods as required.
Containers	CPU and memory quotas of the container allowed for the selected add-on specifications. If you select Custom, you can adjust the container specifications as required.

Select Single or Custom for Add-on Specifications.
- Pods: Set the number of pods based on service requirements.
- Containers: Set a proper container quota based on service requirements.

Configure scheduling policies for the add-on.

Scheduling policies do not take effect on add-on instances of the DaemonSet type.
When configuring multi-AZ deployment or node affinity, ensure that there are nodes meeting the scheduling policy and that resources are sufficient in the cluster. Otherwise, the add-on cannot run.

**Table 2** Configurations for add-on scheduling
Parameter	Description
Multi-AZ Deployment	Preferred: Deployment pods of the add-on will be preferentially scheduled to nodes in different AZs. If all the nodes in the cluster are deployed in the same AZ, the pods will be scheduled to that AZ. Forcible: Deployment pods of the add-on will be forcibly scheduled to nodes in different AZs. If there are fewer AZs than pods, the extra pods will fail to run.
Node Affinity	Incompatibility: Node affinity is disabled for the add-on. Node Affinity: Specify the nodes where the add-on is deployed. If you do not specify the nodes, the add-on will be randomly scheduled based on the default cluster scheduling policy. Specified Node Pool Scheduling: Specify the node pool where the add-on is deployed. If you do not specify the node pool, the add-on will be randomly scheduled based on the default cluster scheduling policy. Custom Policies: Enter the labels of the nodes where the add-on is to be deployed for more flexible scheduling policies. If you do not specify node labels, the add-on will be randomly scheduled based on the default cluster scheduling policy. If multiple custom affinity policies are configured, ensure that there are nodes that meet all the affinity policies in the cluster. Otherwise, the add-on cannot run.
Taints and Tolerations	Using both taints and tolerations allows (not forcibly) the add-on Deployment to be scheduled to a node with the matching taints, and controls the Deployment eviction policies after the node where the Deployment is located is tainted. The add-on adds the default tolerance policy for the node.kubernetes.io/not-ready and node.kubernetes.io/unreachable taints, respectively. The tolerance time window is 60s. For details, see Taints and Tolerations.