ACK One registered clusters provide the node pool feature to manage nodes in groups. A node pool is a group of nodes that have the same configurations, such as instance specifications, operating system, labels, and taints. You can create one or more node pools of different types and configurations in a cluster. The configurations of a node pool consist of node attributes, such as the node specifications, zones, operating system, labels, and taints. You can create a node pool and manage nodes in the node pool in a centralized manner.
Before you create a node pool, we recommend that you read Connect to ECS resources in the cloud to learn about the basic information, scenarios, related features, and billing of node pools.
Before you begin
An ACK One registered cluster is created and an external Kubernetes cluster deployed in an on-premises data center is connected to the ACK One registered cluster.
The network of the external Kubernetes cluster is connected to the virtual private cloud (VPC) of the ACK One registered cluster. For more information, see Scenario-based networking for VPC connections.
You must import the proxy configuration of the external Kubernetes cluster to the ACK One registered cluster in private network mode. For more information, see Associate an external Kubernetes cluster with an ACK One registered cluster.
The self-managed Kubernetes cluster in your data center must be created by using kubeadm and run Kubernetes 1.26, 1.28, 1.30, 1.31, or a later version.
NoteIf your cluster does not meet this requirement, you must create a custom script for the node pool in advance.
Console operations
On the Node Pools page of the cluster that you want to manage in the ACK console, you can create, edit, or delete a node pool. You can also view the details of a node pool.
Log on to the ACK console. In the navigation pane on the left, click Clusters.
On the Clusters page, find the cluster to manage and click its name. In the left-side navigation pane, choose .
Create a node pool
When you create a node pool in the ACK console, you can configure the basic, network, and storage configurations. Some node pool parameters, especially the parameters related to the node pool availability and network, cannot be modified after the node pool is created. The following tables describe these parameters. Creating a node pool in a cluster does not affect the nodes and applications deployed in other node pools of the cluster.
On the Node Pools page, click Create Node Pool. In the Create Node Pool dialog box, configure the node pool parameters.
After you create the node pool, you can modify the node pool parameters on the Edit Node Pool page. The Modifiable column in the following tables indicates whether the corresponding parameter can be modified after the node pool is created.
indicates that the parameter cannot be modified.
indicates that the parameter can be modified.
Basic configuration
Parameter
Description
Can be modified
Node Pool Name
Specify a node pool name.
Region
By default, the region in which the cluster resides is selected. You cannot change the region.
Scaling Mode
Manual and Auto are supported. Computing resources are automatically adjusted based on your business requirements and policies to reduce cluster costs.
Manual: ACK adjusts the number of nodes in the node pool based on the specified Expected Nodes value to maintain the number of nodes at the Expected Nodes value. For more information, see Manually scale a node pool.
Auto: When the capacity planning of the cluster cannot meet the requirements of pod scheduling, ACK automatically scales out nodes based on the configured minimum and maximum number of instances. By default, node instant scaling is enabled for clusters running Kubernetes 1.24 and later, and node auto scaling is enabled for clusters running Kubernetes versions earlier than 1.24. For more information, see Node scaling.
Network settings
Parameter
Description
Modifiable
Network Settings
VPC
By default, the virtual private cloud (VPC) in which the cluster resides is selected. You cannot change the VPC.
vSwitch
When the node pool is being scaled out, new nodes are created in the zones of the selected vSwitches based on the policy that you select for the Scaling Policy parameter. You can select vSwitches in the zones that you want to use.
If no vSwitch is available, click Create vSwitch to create one. For more information, see Create and manage vSwitches.
Instance and image configurations
Parameter
Description
Can be modified
Billing Method
The default billing method used when ECS instances are scaled in a node pool. You can select Pay-As-You-Go, Subscription, or Preemptible Instance.
If you select the Subscription billing method, you must configure the Duration parameter and choose whether to enable Auto Renewal.
Preemptible Instance: ACK supports only Preemptible Instance with a protection period. You must also configure the Upper Price Limit of Current Instance Spec parameter.
If the real-time market price of an instance type that you select is lower than the value of this parameter, a preemptible instance of this instance type is created. After the protection period (1 hour) ends, the system checks the spot price and resource availability of the instance type every 5 minutes. If the real-time market price exceeds your bid price or if the resource inventory is insufficient, the preemptible instance is released. For more information, see Best practices for preemptible instance-based node pools.
To ensure that all nodes in a node pool use the same billing method, ACK does not allow you to change the billing method of a node pool from pay-as-you-go or subscription to preemptible instances or from preemptible instances to pay-as-you-go or subscription.
ImportantIf you change the billing method of a node pool, the change takes effect only on newly added nodes. The existing nodes in the node pool still use the original billing method. For more information about how to change the billing method of existing nodes in a node pool, see Change the billing method from pay-as-you-go to subscription.
To ensure that all nodes use the same billing method, ACK does not allow you to change the billing method of a node pool from pay-as-you-go or subscription to preemptible instances, or change the billing method of a node pool from preemptible instances to pay-as-you-go or subscription.
Instance-related parameters
Select the ECS instances used by the worker node pool based on instance types or attributes. You can filter instance families by attributes such as vCPU, memory, instance family, and architecture. For more information about the instance specifications not supported by ACK and how to configure nodes, see ECS specification recommendations for ACK clusters.
When the node pool is scaled out, ECS instances of the selected instance types are created. The scaling policy of the node pool determines which instance types are used to create new nodes during scale-out activities. Select multiple instance types to improve the success rate of node pool scale-out operations.
If the node pool fails to be scaled out because the instance types are unavailable or the instances are out of stock, you can specify more instance types for the node pool. The ACK console automatically evaluates the scalability of the node pool. You can check the scalability of the node pool when you create the node pool or after you create the node pool.
Operating System
Marketplace Image is in public preview.
Public Image: Container Service for Kubernetes provides public images such as Alibaba Cloud Linux 3 Container Edition, ContainerOS, Alibaba Cloud Linux 3, and Ubuntu. For more information, see Operating systems.
Custom Image: Use a custom operating system image. For more information, see How do I create a custom image based on an existing ECS instance and use it to create nodes?
NoteFor more information about how to upgrade or change the operating system, see Change the operating system. After you change the OS image of the node pool, the change takes effect only on newly added node. The existing nodes in the node pool still use the original OS image.
Security Hardening
Enable security hardening for the cluster. You cannot modify this parameter after the cluster is created.
Disable: disables security hardening for ECS instances.
MLPS Security Hardening: Alibaba Cloud provides baselines and the baseline check feature to help you check the compliance of Alibaba Cloud Linux 2 images and Alibaba Cloud Linux 3 images with the level 3 standards of Multi-Level Protection Scheme (MLPS) 2.0. MLPS Security Hardening enhances the security of OS images to meet the requirements of GB/T 22239-2019 Information Security Technology - Baseline for Classified Protection of Cybersecurity without compromising the compatibility and performance of the OS images. For more information, see ACK security hardening based on MLPS.
ImportantAfter you enable MLPS Security Hardening, remote logons through SSH are prohibited for root users. You can use Virtual Network Computing (VNC) to log on to the OS from the ECS console and create regular users that are allowed to log on through SSH. For more information, see Connect to an instance by using VNC.
OS Security Hardening: You can enable Alibaba Cloud Linux Security Hardening only when the system image is an Alibaba Cloud Linux 2 or Alibaba Cloud Linux 3 image.
Logon Type
If you select MLPS Reinforcement, only Set Password is supported.
Key Pair and Set Password are supported.
Key Pair: An SSH key pair is a secure and convenient authentication method that is provided by Alibaba Cloud. A key pair consists of a public key and a private key. Only Linux instances are supported.
You must also configure Username (root or ecs-user) and Key Pair.
Set Password: The password must be 8 to 30 characters in length and must contain uppercase letters, lowercase letters, digits, and special characters.
You must also configure Username (root or ecs-user) and a password.
Username
If you select Key Pair or Password for Logon Type, you must select root or ecs-user as the username.
Storage configurations
Parameter
Description
Can be modified
System Disk
ESSD AutoPL, Enterprise SSD (ESSD), ESSD Entry, Standard SSD, and Ultra Disk are supported. The types of system disks that you can select vary based on the instance families that you select. Disk types that are not displayed in the drop-down list are not supported by the instance types that you select.
You can select More System Disk Types and select a disk type other than the current one in the System Disk section to improve the success rate of system disk creation. The system will attempt to create a system disk based on the specified disk types in sequence.
Data Disk
ESSD AutoPL, Enterprise SSD (ESSD), ESSD Entry, SSD, and Ultra Disk are supported. The data disk types that you can select vary based on the instance families that you select. Disk types that are not displayed in the drop-down list are not supported by the instance types that you select.
You can select Encryption for all disk types when you specify the type of data disk. By default, the default service CMK is used to encrypt the data disk. You can also use an existing CMK generated by using BYOK in KMS.
You can also use snapshots to create data disks in scenarios where container image acceleration and fast loading of large language models (LLMs) are required. This improves the system response speed and enhances the processing capability.
Make sure that a data disk is mounted to
/var/lib/container
on each node, and/var/lib/kubelet
and/var/lib/containerd
are mounted to the/var/lib/container
. For other data disks on the node, you can perform the initialization operation and customize their mount directories. For more information, see Can I mount a data disk to a custom directory in an ACK node pool?
NoteUp to 64 data disks can be attached to an ECS instance. The number of disks that can be attached to an ECS instance varies based on the instance type. To query the maximum number of data disks supported by each instance type, call the DescribeInstanceTypes operation and query the DiskQuantity parameter in the response.
You can configure the Add Data Disk Type parameter. This parameter allows you to configure a different disk type from the system disk, which increases the success rate of scaling. When creating an instance, the system selects the first matching disk type based on the specified order of disk types for the instance creation.
Number of instances
Parameter
Description
Can be modified
Expected Nodes
The expected number of nodes in the node pool. We recommend that you configure at least two nodes to ensure that cluster components run as expected. You can scale the node pool in or out by adjusting the expected number of nodes. For more information, see Manually scale a node pool.
If you do not want to create nodes in the node pool, set this parameter to 0. You can manually modify this parameter to add nodes later.
Advanced configuration
Click Show Advanced Options (Optional) to configure node scaling policies, resource groups, ECS tags, and taints.
Click Confirm.
In this page, you can click Generate API Request Parameters in the top-left corner to produce Terraform or SDK sample parameters that match your node pool configuration.
Click Confirm. Then, in the node pool list:
Initializing status indicates the node pool is being created.
Active status indicates successful creation.
Edit a node pool
After you create a node pool, ACK One registered clusters allow you to modify some parameters of the node pool in the console. The parameters include the vSwitch, billing method, instance type, system disk, and whether to enable or disable elastic scaling. You can refer to the parameter descriptions in Create a node pool to learn about the parameters that can be modified.
Modifying a node pool does not affect the nodes and applications deployed in other node pools of the cluster.
In most scenarios, after you modify a node pool, the modified configurations apply only to newly added nodes. In specific scenarios, such as when you update the ECS tags or labels and taints of existing nodes, the modified configurations also apply to existing nodes in the node pool.
When you change the Scaling Mode of the node pool, note the following items:
Switching from Manual to Auto: Enables auto scaling and configures the minimum and maximum instance numbers.
Switching from Auto to Manual: Disables auto scaling and sets the minimum instance number to 0 and the maximum instance number to 2000. The value of Expected Nodes is automatically configured to the current number of nodes in the node pool.
After you update the configurations of a node pool, nodes that are subsequently added to the node pool use the modified configurations.
To modify the node pool configuration, refer to the following steps. If you have made changes to the nodes through other methods, these changes will be overwritten when the node pool is updated.
On the Node Pools page, find the node pool that you want to modify and click Edit in the Actions column.
In the dialog box that appears, modify the parameters of the node pool based on the on-screen instructions.
On the Node Pools page, if the Status column of the node pool displays Updatng, the node pool is being modified. After the node pool is updated, the Status column displays Activated.
View node pools
You can view the basic information, monitoring information, all nodes in the node pool, and node scaling activities.
Click the name of the node pool that you want to manage to view the following information on the details page of the node pool:
Basic Information tab: displays the cluster information, node pool information, and node configuration information. If the cluster has auto scaling enabled, you can also view the auto scaling configurations.
Monitoring tab: integrates with Prometheus Service to display the resource usage of the node pool, including CPU or memory usage, disk usage, and average CPU or memory usage of nodes.
Nodes tab: displays all nodes in the node pool. You can remove, maintain, drain, and schedule nodes. Click Export to export node information to a CSV file.
Scaling Activities tab: displays the recent node scaling activities, including the number of instances after scaling and the description of the scaling activity. You can also view the reasons for scaling failures. For more information about error codes for scaling failures, see Error codes for scaling failures and solutions.
Delete a node pool
The release rules of an ECS instance vary based on the billing method of the instance. When you remove a node from a node pool, we recommend that you perform the operations described in the following table. Before you delete a node pool, check whether the Expected Nodes parameter is configured for the node pool. This parameter may affect the node release process.
Node pool | Release rule |
Node pool that is configured with the Expected Nodes parameter |
|
Node pool that is not configured with the Expected Nodes parameter |
|
Optional: Click the name of the node pool that you want to manage. On the Overview tab, you can check whether the Expected Nodes parameter is configured. If a hyphen (-) is displayed, the Expected Nodes parameter is not configured.
Find the node pool you want to delete and choose
> Delete in the Actions column. Read and confirm the information in the dialog box and click OK.