Parameter | Description | Modifiable |
Resource Group | The resource group to which the cluster belongs. Each resource can belong to only one resource group. You can regard a resource group as a project, an application, or an organization based on your business scenarios. | 
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Scaling Mode | You must select Auto for the Scaling Mode. Standard mode: Auto scaling is implemented by creating and releasing ECS instances. Swift mode: Auto scaling is implemented by creating, stopping, and starting ECS instances. ECS instances in the Stopped state can be directly restarted to accelerate scaling activities. When a node in swift mode is reclaimed, only disk fees are charged for the node. No computing fee is charged. This rule does not apply to instance families that use local disks, such as big data and local SSDs instance families. For more information about the billing rules and limits of the economical mode, see Economical mode.
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Scaling Policy | Priority: The system scales the node pool based on the priorities of the vSwitches that you select for the node pool. The vSwitches that you select are displayed in descending order of priority. If Auto Scaling fails to create ECS instances in the zone of the vSwitch with the highest priority, Auto Scaling attempts to create ECS instances in the zone of the vSwitch with a lower priority. Cost Optimization: The system creates instances based on the vCPU unit prices in ascending order. If the Billing Method of the node pool is set to Preemptible Instance, preemptible instances are preferentially created. You can also set the Percentage of Pay-as-you-go Instances parameter. If preemptible instances cannot be created due to reasons such as insufficient stocks, pay-as-you-go instances are automatically created as supplement. Distribution Balancing: The even distribution policy takes effect only when you select multiple vSwitches. This policy ensures that ECS instances are evenly distributed among the zones (the vSwitches) of the scaling group. If ECS instances are unevenly distributed across the zones due to reasons such as insufficient stocks, you can perform a rebalancing operation.
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Use Pay-as-you-go Instances When Preemptible Instances Are Insufficient | You must set the Billing Method parameter to Preemptible Instance. After this feature is enabled, if enough preemptible instances cannot be created because of price or inventory constraints, ACK automatically creates pay-as-you-go instances to meet the required number of ECS instances. | 
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Enable Supplemental Preemptible Instances | You must set the Billing Method parameter to Preemptible Instance. After this feature is enabled, when a system message that indicates preemptible instances are reclaimed is received, the node pool with auto scaling enabled attempts to create new instance to replace the reclaimed the preemptible instances. | 
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ECS Tags | Add tags to the ECS instances that are automatically added during auto scaling. Tag keys must be unique. A key cannot exceed 128 characters in length. Keys and values cannot start with aliyun or acs: . Keys and values cannot contain https:// or http:// . An ECS instance can have up to 20 tags. To increase the quota limit, submit an application in the Quota Center console. The following tags are automatically added to an ECS node by ACK and Auto Scaling. Therefore, you can add at most 17 tags to an ECS node. Note After you enable auto scaling, the following ECS tags are added to the node pool by default: k8s.io/cluster-autoscaler:true and k8s.aliyun.com:true . The auto scaling component simulates scale-out activities based on node labels and taints. To meet this purpose, the format of node labels is changed to k8s.io/cluster-autoscaler/node-template/label/Label key:Label value and the format of taints is changed to k8s.io/cluster-autoscaler/node-template/taint/Taint key/Taint value:Taint effect .
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Taints | Add taints to nodes. A taint consists of a key, a value, and an effect. A taint key can be prefixed. If you want to specify a prefixed taint key, add a forward slash (/) between the prefix and the remaining content of the key. For more information, see Taints and tolerations. The following limits apply to taints: Key: A key must be 1 to 63 characters in length, and can contain letters, digits, hyphens (-), underscores (_), and periods (.). A key must start and end with a letter or digit. If you want to specify a prefixed key, the prefix must be a subdomain name. A subdomain name consists of DNS labels that are separated by periods (.), and cannot exceed 253 characters in length. It must end with a forward slash (/). For more information about subdomain names, see DNS subdomain names. Value: A value cannot exceed 63 characters in length, and can contain letters, digits, hyphens (-), underscores (_), and periods (.). A value must start and end with a letter or digit. You can also leave a value empty. You can specify the following effects for a taint: NoSchedule, NoExecute, and PreferNoSchedule. NoSchedule: If a node has a taint whose effect is NoSchedule, the system does not schedule pods to the node. NoExecute: Pods that do not tolerate this taint are evicted after this taint is added to a node. Pods that tolerate this taint are not evicted after this taint is added to a node. PreferNoSchedule: The system attempts to avoid scheduling pods to nodes with taints that are not tolerated by the pods.
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Node Labels | Add labels to nodes. A label is a key-value pair. A label key can be prefixed. If you want to specify a prefixed label key, add a forward slash (/) between the prefix and the remaining content of the key. The following limits apply to labels: Key: The name must be 1 to 63 characters in length, and can contain letters, digits, hyphens (-), underscores (_), and periods (.). It must start and end with a letter or a digit. If you want to specify a prefixed label key, the prefix must be a subdomain name. A subdomain name consists of DNS labels that are separated by periods (.), and cannot exceed 253 characters in length. It must end with a forward slash (/).
The following prefixes are used by key Kubernetes components and cannot be used in node labels:
Value: A value cannot exceed 63 characters in length, and can contain letters, digits, hyphens (-), underscores (_), and periods (.). A value must start and end with a letter or digit. You can also leave a value empty.
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Container Image Acceleration | Only clusters that use containerd versions 1.6.34 and later supports this configuration. After you select this option, new nodes automatically detect whether container images support on-demand loading. If supported, container startups will be accelerated by using on-demand loading. | 
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CPU Policy | | 
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Custom Node Name | Specify whether to use a custom node name. If you choose to use a custom node name, the name of the node, name of the ECS instance, and hostname of the ECS instance are changed. Note If a Windows instance uses a custom node name, the hostname of the instance is fixed to an IP address. You need to use hyphens (- ) to replace the periods (. ) in the IP address. In addition, no prefix or suffix is allowed in the IP address. A custom node name consists of a prefix, an IP substring, and a suffix. A custom node name must be 2 to 64 characters in length. The name must start and end with a lowercase letter or digit. The prefix and suffix can contain letters, digits, hyphens (-), and periods (.). The prefix and suffix must start with a letter and cannot end with a hyphen (-) or period (.). The prefix and suffix cannot contain consecutive hyphens (-) or periods (.). The prefix is required due to ECS limits and the suffix is optional.
For example, the node IP address is 192.XX.YY.55, the prefix is aliyun.com, and the suffix is test. If the node is a Linux node, the node name, ECS instance name, and ECS instance hostname are aliyun.com192.XX.YY.55test. If the node is a Windows node, the ECS instance hostname is 192-XX-YY-55 and the node name and ECS instance name are aliyun.com192.XX.YY.55test.
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Worker RAM Role | ACK managed clusters that run Kubernetes 1.22 or later are supported. You can assign a worker Resource Access Management (RAM) role to a node pool to reduce the potential risk of sharing a worker RAM role among all nodes in the cluster. Default Role: The node pool uses the default worker RAM role created by the cluster. Custom: The node pool uses the specified role as the worker RAM role. The default role is used when this parameter is left empty. For more information, see Use custom worker RAM roles.
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Pre-defined Custom Data | To use this feature, submit an application in the Quota Center console. Nodes automatically run predefined scripts before they are added to the cluster. For more information about user-data scripts, see User-data scripts. For example, if you enter echo "hello world" , a node runs the following script:
#!/bin/bash
echo "hello world"
[Node initialization script]
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User Data | Nodes automatically run user-data scripts after they are added to the cluster. For more information about user-data scripts, see User-data scripts. For example, if you enter echo "hello world" , a node runs the following script:
#!/bin/bash
[Node initialization script]
echo "hello world"
Note After you create a cluster or add nodes, the execution of the user-data script on a node may fail. We recommend that you log on to a node and run the grep cloud-init/var/log/messages command to view the execution log and check whether the execution succeeds or fails on the node. | 
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CloudMonitor Agent | After you install CloudMonitor, you can view the monitoring information about the nodes in the CloudMonitor console. This parameter takes effect only on newly added nodes and does not take effect on existing nodes. If you want to install the CloudMonitor agent on an existing ECS node, go to the CloudMonitor console. | 
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Public IP | Specify whether to assign an IPv4 address to each node. If you clear the check box, no public IP address is allocated. If you select the check box, you must configure the Bandwidth Billing Method and Peak Bandwidth parameters. This parameter takes effect only on newly added nodes and does not take effect on existing nodes. If you want to enable an existing node to access the Internet, you must create an EIP and associate the EIP with the node. For more information, see Associate an EIP with an ECS instance. | 
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Custom Security Group | You can select Basic Security Group or Advanced Security Group, but you can select only one security group type. You cannot modify the security groups of node pools or change the type of security group. For more information about security groups, see Overview. Important Each ECS instance supports up to five security groups. Make sure that the quota of security groups for your ECS instance is sufficient. For more information about security group limits and how to increase the quota limit of security groups for your ECS instance, see Security group limits. If you select an existing security group, the system does not automatically configure security group rules. This may cause errors when you access the nodes in the cluster. You must manually configure security group rules. For more information about how to manage security group rules, see Configure security group rules to enforce access control on ACK clusters.
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RDS Whitelist | Add node IP addresses to the whitelist of an ApsaraDB RDS instance. | 
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Deployment Set | You must first create a deployment set in the ECS console and then specify the deployment set when you create a node pool in the ACK console. The deployment set cannot be modified after the cluster is created. You can use a deployment set to distribute your ECS instances to different physical servers to ensure high service availability and implement underlying disaster recovery. If you specify a deployment set when you create ECS instances, the instances are created and distributed based on the deployment strategy that you preset for the deployment set within the specified region. For more information, see Best practices for associating deployment sets with node pools. Important After you select a deployment set, the maximum number of nodes that can be created in the node pool is limited. By default, the maximum number of nodes supported by a deployment set is 20 × Number of zones . The number of zones depends on the number of vSwitches. Exercise caution when you select the deployment set. To avoid node creation failures, make sure that the ECS quota of the deployment set that you select is sufficient. | 
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Private Pool Type | Valid values: Open, Do Not Use, and Specified. Open: The system automatically matches an open private pool. If no matching is found, resources in the public pool are used. Do Not Use: No private pool is used. Only resources in the public pool are used. Specified: Specify a private pool by ID. If the specified private pool is unavailable, ECS instances fail to start up.
For more information, see Private pools. | 
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