Updating an AS Configuration¶
Auto Scaling (AS) enables elastic scaling of nodes in a node pool based on scaling policies. Without this function, you have to manually adjust the number of nodes in a node pool.
Constraints¶
To enable AS, the CCE Cluster Autoscaler add-on must be installed in the target cluster.
Procedure¶
Log in to the CCE console and click the cluster name to access the cluster console.
In the navigation pane, choose Nodes. On the Node Pools tab, locate the row containing the target node pool and click Auto Scaling.
If the auto scaling add-on has not been installed, configure add-on parameters based on service requirements, click Install, and wait until the add-on is installed. For details about add-on configurations, see CCE Cluster Autoscaler.
If the auto scaling add-on has been installed, directly configure auto scaling policies.
Configure auto scaling policies.
AS Configuration
Customize scale-out rules.: Click Add Rule. In the dialog box displayed, configure parameters. You can add multiple node scaling rules, a maximum of one CPU usage-based rule, and one memory usage-based rule. The total number of rules cannot exceed 10.
The following table lists custom rules.
Table 1 Custom rules¶ Rule Type
Configuration
Metric-based
Trigger: Select CPU allocation rate or Memory allocation rate and enter a value. The value must be greater than the scale-in percentage configured in the auto scaling add-on.
Note
Resource allocation (%) = Resources requested by pods in the node pool/Resources allocatable to pods in the node pool
If multiple rules meet the conditions, the rules are executed in either of the following modes:
If rules based on the CPU allocation rate and memory allocation rate are configured and two or more rules meet the scale-out conditions, the rule that will add the most nodes will be executed.
If a rule based on the CPU allocation rate and a periodic rule are configured and they both meet the scale-out conditions, one of them will be executed randomly. The rule executed first (rule A) changes the node pool to the scaling state. As a result, the other rule (rule B) cannot be executed. After rule A is executed and the node pool status becomes normal, rule B will not be executed.
If rules based on the CPU allocation rate and memory allocation rate are configured, the policy detection period varies with the processing logic of each loop of the Autoscaler add-on. A scale-out is triggered once the conditions are met, but it is constrained by other factors such as the cooldown period and node pool status.
When the number of nodes in the cluster reaches the upper limit, or the CPU or memory usage reaches the upper limit of the autoscaler add-on, node scale-out will not be triggered.
Action: Configure an action to be performed when the triggering condition is met.
Custom: Add a specified number of nodes to a node pool.
Auto calculation: When the trigger condition is met, nodes are automatically added and the allocation rate is restored to a value lower than the threshold. The formula is as follows:
Number of nodes to be added = [Resource request of pods in the node pool/(Available resources of a single node x Target allocation rate)] - Number of current nodes + 1
Periodic
Trigger Time: You can select a specific time every day, every week, every month, or every year.
Action: specifies an action to be carried out when the trigger time is reached. A specified number of nodes will be added to the node pool.
Nodes: The number of nodes in a node pool will always be within the range during auto scaling.
Cooldown Period: a period during which the nodes added in the current node pool cannot be scaled in.
AS Object
Specifications: Configure whether to enable auto scaling for node flavors in a node pool.
Click OK.