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qiujiandong1 ab1e53a279 CCE UMN 20251031 version 
Reviewed-by: Gergo-Bence Lorincz <a200452876@noreply.gitea.eco.tsi-dev.otc-service.com>
Co-authored-by: qiujiandong1 <qiujiandong1@huawei.com>
Co-committed-by: qiujiandong1 <qiujiandong1@huawei.com>
2026-01-15 10:25:22 +00:00

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Enabling Overload Control for a Cluster

Cluster overload occurs when the system load such as request volume or resource usage exceeds the system's processing capacity, leading to degraded performance or system failure. Overload control is a dynamic mechanism that limits concurrent external requests based on the resources of the master nodes, ensuring the stability and reliability of the master nodes and the cluster. In a CCE standard or Turbo cluster, you can enable cluster overload control, monitor cluster overload, and configure overload alarms to reduce the risk of cluster overload. For details, see Figure 1.

Figure 1 Process of cluster overload control

Constraints

The cluster version must be v1.23 or later.

Enabling Overload Control During Cluster Creation

  1. When creating a cluster v1.23 or later, enable Overload Control in Advanced Settings (Optional) > Cluster Scalability on the Create Cluster page. After this function is enabled, CCE will dynamically adjust concurrent requests based on the resource demands received by master nodes to ensure the stability and reliability of the master nodes and the cluster.

  2. Click the cluster name to go to the cluster Overview page. In the Master Nodes area at the lower right of the page, verify that overload control has been enabled. If "Overload control enabled. An overloaded master node rejects external traffic proportionally based on the overload level." is displayed, overload control has been enabled.

Enabling Overload Control for an Existing Cluster

Enabling cluster overload control for an existing cluster will restart kube-apiserver. So, enable this function during off-peak hours.

  1. Log in to the CCE console and click the name of an existing cluster whose version is v1.23 or later. The cluster Overview page is displayed.
  2. In the Master Nodes area at the lower right of the page, click Enable.
  3. In the Master Nodes area, overload control has been enabled if the following information is displayed: Overload control enabled. An overloaded master node rejects external traffic proportionally based on the overload level.

Overload Monitoring

You can monitor cluster metrics to promptly check the cluster overload status.

  1. Log in to the CCE console and click the name of an existing cluster whose version is v1.23 or later.
  2. On the Overview page, check the master node information. The overload level metric will be displayed.

    The overload levels are as follows:
    • Circuit breaking: Rejects all external traffic.
    • Severe overload: Rejects 75% external traffic.
    • Moderate overload: Rejects 50% external traffic.
    • Slight overload: Rejects 25% external traffic.
    • Normal: Does not reject external traffic.

Disabling Cluster Overload Control

You can disable overload control when it is no longer needed. After overload control is disabled, the master node will no longer reject external traffic when overloaded. Exercise caution when performing this operation.

  1. Log in to the CCE console and click the name of an existing cluster whose version is v1.23 or later.
  2. In the navigation pane, choose Settings.
  3. On the Cluster Access tab, disable overload control.
  4. Click OK.
Parent topic: Managing Clusters