Modifying Cluster Configurations

Scenario

CCE allows you to manage cluster parameters, through which you can let core components work under your requirements.

Procedure

Log in to the CCE console. In the navigation pane, choose Clusters.
Locate the target cluster, click ... to view more operations on the cluster, and choose Manage.

On the Manage Component page, change the values of the Kubernetes parameters listed in the following table.

**Table 1** kube-apiserver configurations
Item	Parameter	Description	Value
Toleration time for nodes in NotReady state	default-not-ready-toleration-seconds	Specifies the default tolerance time. The configuration takes effect for all pods by default. You can configure different tolerance time for pods. In this case, the tolerance time configured for the pod is used. For details, see Configuring Tolerance Policies. If the specified tolerance time is too short, pods may be frequently migrated in scenarios like a network jitter. If the specified tolerance time is too long, services may be interrupted during this period after the node is faulty.	Default: 300s
Toleration time for nodes in unreachable state	default-unreachable-toleration-seconds	Specifies the default tolerance time. The configuration takes effect for all pods by default. You can configure different tolerance time for pods. In this case, the tolerance time configured for the pod is used. For details, see Configuring Tolerance Policies. If the specified tolerance time is too short, pods may be frequently migrated in scenarios like a network jitter. If the specified tolerance time is too long, services may be interrupted during this period after the node is faulty.	Default: 300s
Maximum Number of Concurrent Modification API Calls	max-mutating-requests-inflight	Maximum number of concurrent mutating requests. When the value of this parameter is exceeded, the server rejects requests. The value 0 indicates that there is no limitation on the maximum number of concurrent modification requests. This parameter is related to the cluster scale. You are advised not to change the value.	Manual configuration is no longer supported since cluster v1.21. The value is automatically specified based on the cluster scale. 200 for clusters with 50 or 200 nodes 500 for clusters with 1000 nodes 1000 for clusters with 2000 nodes
Maximum Number of Concurrent Non-Modification API Calls	max-requests-inflight	Maximum number of concurrent non-mutating requests. When the value of this parameter is exceeded, the server rejects requests. The value 0 indicates that there is no limitation on the maximum number of concurrent non-modification requests. This parameter is related to the cluster scale. You are advised not to change the value.	Manual configuration is no longer supported since cluster v1.21. The value is automatically specified based on the cluster scale. 400 for clusters with 50 or 200 nodes 1000 for clusters with 1000 nodes 2000 for clusters with 2000 nodes
NodePort port range	service-node-port-range	NodePort port range. After changing the value, go to the security group page and change the TCP/UDP port range of node security groups 30000 to 32767. Otherwise, ports other than the default port cannot be accessed externally. If the port number is smaller than 20106, a conflict may occur between the port and the CCE health check port, which may further lead to unavailable cluster. If the port number is greater than 32767, a conflict may occur between the port and the ports in net.ipv4.ip_local_port_range, which may further affect the network performance.	Default: 30000 to 32767 Value range: Min > 20105 Max < 32768
Overload Control	support-overload	Cluster overload control. After this function is enabled, concurrent requests will be dynamically controlled based on the resource demands received by master nodes to ensure the stable running of the master nodes and the cluster. This parameter is available only in clusters of v1.23 or later.	false: Overload control is disabled. true: Overload control is enabled.
Node Restriction Add-on	enable-admission-plugin-node-restriction	This add-on allows the kubelet of a node to operate only the objects of the current node for enhanced isolation in multi-tenant scenarios or the scenarios with high security requirements. This parameter is available only in clusters of v1.23.14-r0, v1.25.9-r0, v1.27.6-r0, v1.28.4-r0, or later versions.	Default: true
Pod Node Selector Add-on	enable-admission-plugin-pod-node-selector	This add-on allows cluster administrators to configure the default node selector through namespace annotations. In this way, pods run only on specific nodes and configurations are simplified. This parameter is available only in clusters of v1.23.14-r0, v1.25.9-r0, v1.27.6-r0, v1.28.4-r0, or later versions.	Default: true
Pod Toleration Limit Add-on	enable-admission-plugin-pod-toleration-restriction	This add-on allows cluster administrators to configure the default value and limits of pod tolerations through namespaces for fine-grained control over pod scheduling and key resource protection. This parameter is available only in clusters of v1.23.14-r0, v1.25.9-r0, v1.27.6-r0, v1.28.4-r0, or later versions.	Default: false

**Table 2** Scheduler configurations
Item	Parameter	Description	Value
Default cluster scheduler	default-scheduler	kube-scheduler scheduler: provides the standard scheduling capability of the community. volcano scheduler: compatible with kube-scheduler scheduling capabilities and provides enhanced scheduling capabilities. For details, see Volcano Scheduling.	Default: kube-scheduler
QPS for communicating with kube-apiserver	kube-api-qps	QPS for communicating with kube-apiserver.	If the number of nodes in a cluster is less than 1000, the default value is 100. If the number of nodes in a cluster is 1000 or more, the default value is 200.
Burst for communicating with kube-apiserver	kube-api-burst	Burst for communicating with kube-apiserver.	If the number of nodes in a cluster is less than 1000, the default value is 100. If the number of nodes in a cluster is 1000 or more, the default value is 200.
Whether to enable GPU sharing	enable-gpu-share	Whether to enable GPU sharing. This parameter is supported only in clusters of v1.23.7-r10, v1.25.3-r0, or later versions. When disabled, ensure that pods in the cluster cannot use shared GPUs (no cce.io/gpu-decision annotation in pods) and that GPU virtualization is disabled. When enabled, ensure that there is a cce.io/gpu-decision annotation on all pods that use GPU resources in the cluster.	Default: true

**Table 3** kube-controller-manager configurations
Item	Parameter	Description	Value
Number of concurrent processing of deployment	concurrent-deployment-syncs	Number of deployment objects that can be synchronized concurrently	Default: 5
Concurrent processing number of endpoint	concurrent-endpoint-syncs	Number of endpoint syncing operations that will be done concurrently	Default: 5
Concurrent number of garbage collector	concurrent-gc-syncs	Number of garbage collector workers that can be synchronized concurrently	Default: 20
Number of job objects allowed to sync simultaneously	concurrent-job-syncs	Number of job objects that can be synchronized concurrently	Default: 5
Number of CronJob objects allowed to sync simultaneously	concurrent-cron-job-syncs	Number of scheduled jobs that can be synchronized concurrently	Default: 5
Number of concurrent processing of namespace	concurrent-namespace-syncs	Number of namespace objects that can be synchronized concurrently	Default: 10
Concurrent processing number of replicaset	concurrent-replicaset-syncs	Number of replica sets that can be synchronized concurrently	Default: 5
Number of concurrent processing of resource quota	concurrent-resource-quota-syncs	Number of resource quotas that can be synchronized concurrently	Default: 5
Concurrent processing number of service	concurrent-service-syncs	Number of services that can be synchronized concurrently	Default: 10
Concurrent processing number of serviceaccount-token	concurrent-serviceaccount-token-syncs	Number of service account token objects that can be synchronized concurrently	Default: 5
Concurrent processing of ttl-after-finished	concurrent-ttl-after-finished-syncs	Number of ttl-after-finished-controller workers that can be synchronized concurrently	Default: 5
RC	concurrent_rc_syncs (used in clusters of v1.19 or earlier) concurrent-rc-syncs (used in clusters of v1.21 through v1.25.3-r0)	Number of replication controllers that can be synchronized concurrently NOTE: This parameter is no longer supported in clusters of v1.25.3-r0 and later versions.	Default: 5
Cluster elastic computing period	horizontal-pod-autoscaler-sync-period	Period for the horizontal pod autoscaler to perform auto scaling on pods. A smaller value will result in a faster auto scaling response and higher CPU load. NOTE: Make sure to configure this parameter properly as a lengthy period can cause the controller to respond slowly, while a short period may overload the cluster control plane.	Default: 15 seconds
Horizontal Pod Scaling Tolerance	horizontal-pod-autoscaler-tolerance	The configuration determines how quickly the horizontal pod autoscaler will act to auto scaling policies. If the parameter is set to 0, auto scaling will be triggered immediately when the related metrics are met. Configuration suggestion: If the service resource usage increases sharply over time, retain a certain tolerance to prevent auto scaling which is beyond expectation in high resource usage scenarios.	Default: 0.1
QPS for communicating with kube-apiserver	kube-api-qps	QPS for communicating with kube-apiserver	If the number of nodes in a cluster is less than 1000, the default value is 100. If the number of nodes in a cluster is 1000 or more, the default value is 200.
Burst for communicating with kube-apiserver	kube-api-burst	Burst for communicating with kube-apiserver	If the number of nodes in a cluster is less than 1000, the default value is 100. If the number of nodes in a cluster is 1000 or more, the default value is 200.
The maximum number of terminated pods that can be kept before the Pod GC deletes the terminated pod	terminated-pod-gc-threshold	Number of terminated pods that can exist in a cluster. If there are more terminated pods than the expected number in the cluster, the terminated pods that exceed the number will be deleted. NOTE: If this parameter is set to 0, all pods in the terminated state are retained.	Default: 1000 Value range: 10 to 12500 If the cluster version is v1.21.11-r40, v1.23.8-r0, v1.25.6-r0, v1.27.3-r0, or later, the value range is changed to 0 to 100000.
Unhealthy AZ Threshold	unhealthy-zone-threshold	When more than a certain proportion of pods in an AZ are unhealthy, the AZ itself will be considered unhealthy, and scheduling pods to nodes in that AZ will be restricted to limit the impacts of the unhealthy AZ. This parameter is available only in clusters of v1.23.14-r0, v1.25.9-r0, v1.27.6-r0, v1.28.4-r0, or later versions. NOTE: If the parameter is set to a large value, pods in unhealthy AZs will be migrated in a large scale, which may lead to risks such as overloaded clusters.	Default: 0.55 Value range: 0 to 1
Node Eviction Rate	node-eviction-rate	This parameter specifies the number of nodes that pods are deleted from per second in a cluster when the AZ is healthy. The default value is 0.1, indicating that pods can be evicted from at most one node every 10 seconds. This parameter is available only in clusters of v1.23.14-r0, v1.25.9-r0, v1.27.6-r0, v1.28.4-r0, or later versions. NOTE: If the parameter is set to a large value, the cluster may be overloaded. Additionally, if too many pods are evicted, they cannot be rescheduled, which will slow down fault recovery.	Default: 0.1
Secondary Node Eviction Rate	secondary-node-eviction-rate	This parameter specifies the number of nodes that pods are deleted from per second in a cluster when the AZ is unhealthy. The default value is 0.01, indicating that pods can be evicted from at most one node every 100 seconds. This parameter is available only in clusters of v1.23.14-r0, v1.25.9-r0, v1.27.6-r0, v1.28.4-r0, or later versions. NOTE: There is no need to set the parameter to a large value for nodes in an unhealthy AZ, and this configuration may result in overloaded clusters.	Default: 0.01 Configure this parameter with node-eviction-rate and set it to one-tenth of node-eviction-rate.
Large Cluster Threshold	large-cluster-size-threshold	If the number of nodes in a cluster is greater than the value of this parameter, this is a large cluster. This parameter is available only in clusters of v1.23.14-r0, v1.25.9-r0, v1.27.6-r0, v1.28.4-r0, or later versions. NOTE: kube-controller-manager automatically adjusts configurations for large clusters to optimize the cluster performance. Therefore, an excessively small threshold for small clusters will deteriorate the cluster performance.	Default: 50 For the clusters with a large number of nodes, configure a relatively larger value than the default one for higher performance and faster responses of controllers. Retain the default value for small clusters. Before adjusting the value of this parameter in a production environment, check the impact of the change on cluster performance in a test environment.

**Table 4** Networking component configurations (supported only by the clusters using a VPC network)
Item	Parameter	Description	Value
Retaining the non-masqueraded CIDR block of the original pod IP address	nonMasqueradeCIDRs	In a CCE cluster using the VPC network model, if a container in the cluster needs to access externally, the source pod IP address must be masqueraded as the IP address of the node where the pod resides through SNAT. After the configuration, the node will not SNAT the IP addresses in the CIDR block by default. This function is available only in clusters of v1.23.14-r0, v1.25.9-r0, v1.27.6-r0, v1.28.4-r0, or later versions. By default, nodes in a cluster do not perform SNAT on packets destined for 10.0.0.0/8, 172.16.0.0/12, or 192.168.0.0/16 that is detected by CCE as a private CIDR block. Instead, these packets are directly transferred using the upper-layer VPC. (The three CIDR blocks are considered as internal networks in the cluster and are reachable at Layer 3 by default.)	Default: 10.0.0.0/8, 172.16.0.0/12, or 192.168.0.0/16 NOTE: To enable cross-node pod access, the CIDR block of the node where the target pod runs must be added. Similarly, to enable cross-ECS pod access in a VPC, the CIDR block of the ECS where the target pod runs must be added.

**Table 5** Extended controller configurations (supported only by clusters of v1.21 and later)
Item	Parameter	Description	Value
Enable resource quota management	enable-resource-quota	Indicates whether to automatically create a ResourceQuota when creating a namespace. With quota management, you can control the number of workloads of each type and the upper limits of resources in a namespace or related dimensions. false: Auto creation is disabled. true: Auto creation is enabled. For details about the resource quota defaults, see Configuring Resource Quotas. NOTE: In high-concurrency scenarios (for example, creating pods in batches), the resource quota management may cause some requests to fail due to conflicts. Do not enable this function unless necessary. To enable this function, ensure that there is a retry mechanism in the request client.	Default: false