Container Service for Kubernetes:Limits

Overview

Before you use ACK, take note of the following limits:

• You must pass real-name verification before you can create an ACK cluster.

• You cannot perform the following operations on an ACK cluster after it is created:

  • Change the virtual private cloud (VPC) in which the cluster resides.

  • Change the cluster type from ACK managed to ACK dedicated or from ACK Pro to ACK standard.

  • Change the network plug-in.

  • Change the volume plug-in.

  • Migrate applications across different namespaces.

• The following limits apply to Elastic Compute Service (ECS) instances in ACK clusters:

  • The pay-as-you-go and subscription billing methods are supported. Other resources, such as Server Load Balancer (SLB) instances, support only the pay-as-you-go billing method. You can change the billing method of an ECS instance from pay-as-you-go to subscription in the ECS console.

  • When you create, expand, or scale out ACK clusters, the system may fail to create ECS nodes if the ECS quota limit is reached or ECS instances are out of stock.

  • If you choose the subscription billing method for ECS instances when you create a cluster, the system may fail to create ECS nodes if the ECS quota limit is reached or ECS instances are out of stock. However, subscription instances that have been created will not be released before their subscriptions expire. You can add these instances to other clusters if needed.

    Note

    To avoid paying for idle resources, we recommend that you choose the pay-as-you-go billing method for ECS instances when you create a cluster. You can change the billing method to subscription in the ECS console if needed.

  • You must select instance types that provide at least 4 vCPUs and 8 GiB of memory.

• Limits on access to control plane components:

  Bandwidth limits apply when you access control pane components, including kube-apiserver and etcd, of a cluster by calling API operations or by using the CLI. If you attempt to read a large number of cluster events at a time, bandwidth throttling may be triggered and you may fail to read the events. We recommend that you query cluster events by using the Kubernetes event center feature of Log Service. Alternatively, you can add paging parameters, such as --chunk-size=500, to the API request or command lines to reduce the number of events to be read per request. If you frequently encounter bandwidth throttling on an ACK standard cluster, we recommend that you migrate workloads from the cluster to an ACK Pro cluster.

  For more information about the Kubernetes event center feature of Log Service, see Scenario 1: Use node-problem-detector with the Kubernetes event center of Log Service to sink cluster events.

  For more information about how to migrate workloads from an ACK standard cluster to an ACK Pro cluster, see Hot migration from ACK basic clusters to ACK Pro clusters.

Resource quota limits

The resource quota limits and use scenarios for ACK Pro clusters are different from the resource limits and use scenarios for ACK standard clusters.

• ACK Pro clusters are ideal for enterprise customers.

  Note

  If you install Terway and enable the Terway IPVLAN mode in an ACK Pro cluster, you can create at most 5,000 nodes, 50,000 pods, and 64,000 mappings between pods and Services in the cluster.

• ACK standard clusters are ideal for individual developers in terms of testing and learning.

Quotas

^①To increase the maximum number of node pools supported by a cluster, you need to submit a ticket to request a quota increase for scaling groups.

^②This quota takes effect only in Flannel network mode and cannot be increased. In Terway network mode, this quota is determined by the number of IP addresses that can be allocated by the node.

^③ACK Serverless clusters do not contain nodes. The quota indicates the maximum number of pods on a node of an ACK Serverless standard cluster and cannot be increased.

Quota limits on underlying cloud resources