Create custom OS images to facilitate auto scaling in complex scenarios - Container Service for Kubernetes

Alicloud Image Builder is an image building tool provided by Alibaba Cloud that simplifies and automates image building. You can use OS images created by using Alicloud Image Builder as custom images to create node pools in Container Service for Kubernetes (ACK) clusters. This allows you to quickly add nodes to ACK clusters. This topic describes how to run Alicloud Image Builder as a Job to create custom OS images in ACK clusters.

Prerequisites

An ACK cluster is created. For more information, see Create an ACK managed cluster.
A kubectl client is connected to the ACK cluster. For more information, see Obtain the kubeconfig file of a cluster and use kubectl to connect to the cluster.

Benefits of custom images

Node pools in ACK clusters support auto scaling. By default, when you create a node pool, you can select OS images such as CentOS and Alibaba Cloud Linux. These OS images meet the requirements of most scenarios. However, in scenarios that require preinstallation or high performance, these images may be unable to meet your business requirements. Alibaba Cloud provides Alicloud Image Builder to help you build custom OS images and facilitate auto scaling in complex scenarios.

To use Alicloud Image Builder to create custom images, you can create a Job or CronJob to distribute the image building task in an ACK cluster.

Create a Job to quickly build a custom OS image

In this example, a ConfigMap named build-config and a Job named build are created to show how to use Alicloud Image Builder to quickly build a custom OS image.

Step 1: Set parameters for the OS image

Create a ConfigMap named build-config to specify the parameters of the OS image.

Create a YAML file named build-config.yaml and add the following content to the file:

YAML template

apiVersion: v1
kind: ConfigMap
metadata:
  name: build-config
data:
  ack.json: |-

    {
      "variables": {
        "image_name": "ack-optimized_image-1.30-{{timestamp}}",
        "source_image": <source_image>,
        "instance_type": <instance_type>,
        "region": "{{env `ALICLOUD_REGION`}}",
        "access_key": "{{env `ALICLOUD_ACCESS_KEY`}}",
        "secret_key": "{{env `ALICLOUD_SECRET_KEY`}}"
      },
      "builders": [
        {
          "type": "alicloud-ecs",
          "system_disk_mapping": {    
                    "disk_size": 120
                    },   # Specify the size of the system disk. Unit: GB. Default value: 40. 
          "access_key": "{{user `access_key`}}",
          "secret_key": "{{user `secret_key`}}",
          "region": "{{user `region`}}",
          "image_name": "{{user `image_name`}}",
          "source_image": "{{user `source_image`}}",
          "ssh_username": "root",
          "vpc_id": "",  # If you do not specify the vpc_id parameter, a virtual private cloud (VPC) is automatically created during the image building process. The VPC is automatically deleted after the image is built. 
          "vswitch_id": "",  # If you do not specify the vswitch_id parameter, a vSwitch is automatically created during the image building process. The vSwitch is automatically deleted after the image is built. 
          "security_group_id": "",   # If you do not specify the security_group_id parameter, a security group is automatically created during the image building process. The security group is automatically deleted after the image is built. 
          "instance_type": "{{user `instance_type`}}",
          "skip_image_validation": "true",
          "io_optimized": "true"
        }
      ],
      "provisioners": [{
       "type": "file",
       "source": "scripts/ack-optimized-os-all.sh",
       "destination": "/root/"
        },
        {
       "type": "shell",
       "inline": [
         "export RUNTIME=containerd",    # Specify the runtime that is used. 
         "export RUNTIME_VERSION=1.6.28",
         "export SKIP_SECURITY_FIX=true",
         "export KUBE_VERSION=1.30.1-aliyun.1",
         "export OS_ARCH=amd64",    # Specify amd64 or arm64 based on your business requirements. 
         "bash /root/ack-optimized-os-all.sh"
      ]
      }]
    }

The following table describes the parameters.

Table 1. Alicloud Image Builder parameters

Parameter	Example	Description
`variables{"<variable1>":"<value>"}`	variables{"access_key":"{{env ALICLOUD_ACCESS_KEY}}"}	The `variables` that are used by Alicloud Image Builder. Note If you write sensitive information such as an AccessKey pair that is specified by using the `access_key` and `secret_key` parameters to the configuration file, the information may be leaked. To ensure data security, you can specify the AccessKey pair as variables. The values of the variables are based on the input values of the runtime.
`builders{"type":"<value>"}`	builders{"type":"alicloud-ecs"}	The image `builders`. If the type parameter is set to aliyun-ecs, a temporary Elastic Compute Service (ECS) instance is created to build the image. The ECS instance is automatically released after the image is built.
`provisioners{"type":"<value>"}`	provisioners{"type":"shell"}	The image `provisioners` that are used to specify the operations to be performed on the temporary instance. If the type parameter is set to shell, a shell provisioner is used. A shell command is automatically run after the Linux instance is connected. For example, you can run the `yum install redis.x86_64 -y` command to install Redis. For more information about how to configure provisioners, see the Provisioner configuration section of this topic.

Table 2. Image building parameters

Parameter	Example	Description	Required/optional
`access_key`	LTAInPyXXXXQ****	The AccessKey ID that is used to create the custom image. For more information, see Obtain an AccessKey pair.	Required
`secret_key`	CM1ycKrrCekQ0dhXXXXXXXXXl7y****	The AccessKey secret that is used to create the custom image.	Required
`region`	cn-beijing	The region in which the custom image is deployed.	Required
`image_name`	ack-custom_image	The name of the custom image. The name must be globally unique.	Required
`source_image`	aliyun_2_1903_x64_20G_alibase_20200904.vhd	The ID of the Alibaba Cloud public image based on which the custom image is created. The created custom image contains the same operating system as the public image. For more information, see the OS images supported by ACK section of the "Overview of OS images" topic.	Required
`instance_type`	ecs.c6.xlarge	The instance type of the ECS instance that is created from the base image specified in the source_image parameter. The ECS instance is used to run the preinstallation task and build the custom image. If you want to use a GPU-accelerated image, specify a GPU-accelerated instance type.	Required
`RUNTIME`	containerd	The container runtime, which can be Docker or containerd.	Required
`RUNTIME_VERSION`	1.6.28	When you select Docker, RUNTIME_VERSION is 19.03.15 by default. When you select containerd, RUNTIME_VERSION is 1.6.20 by default.	Optional
`SKIP_SECURITY_FIX`	true	Specifies whether to skip security update.	Required
`KUBE_VERSION`	1.30.1-aliyun.1	The Kubernetes version of the cluster.	Required
`PRESET_GPU`	true	Specifies whether to preinstall a GPU driver to accelerate startup.	Optional
`NVIDIA_DRIVER_VERSION`	460.91.03	The version of the preinstalled GPU driver. If you do not specify this parameter, the default value 460.91.03 is used.	Optional
`OS_ARCH`	amd64	The CPU architecture. Valid values: amd64 and arm64.	Required
MOUNT_RUNTIME_DATADISK	true	Set the value to true if you want to mount a disk volume created from a volume image to the ECS instance when the system installs the custom image.	Optional

Important

Before you specify a custom image for a node pool, make sure that the configurations of the node pool are the same as the build settings of the custom image. Otherwise, nodes created from the custom image cannot be added to the cluster. The configurations of the node pool include the cluster version, container runtime, and GPU-accelerated instance type.
When you verify the custom image, select a regular node pool that uses the same build settings as the custom image. After you use the custom image to create nodes and add the nodes to the node pool, check whether your application can run on the nodes as expected.

Run the following command to deploy Alicloud Image Builder in the cluster:
```
kubectl apply -f build-config.yaml
```

Step 2: Create a Job to build a custom OS image

Use the following YAML template to grant permissions to the account that uses the AccessKey pair.

YAML template

{
  "Version": "1",
  "Statement": [
    {
      "Action": [
        "ecs:DeleteInstance",
        "ecs:StartInstance",
        "ecs:StopInstance",
        "ecs:DescribeInstances"
      ],
      "Resource": "*",
      "Effect": "Allow"
    },
    {
      "Action": [
        "ecs:CreateInstance",
        "ecs:DescribeImages",
        "ecs:CreateImage",
        "ecs:ModifyImageSharePermission",
        "ecs:CreateKeyPair",
        "ecs:DeleteKeyPairs",
        "ecs:DetachKeyPair",
        "ecs:AttachKeyPair",
        "ecs:CreateSecurityGroup",
        "ecs:DeleteSecurityGroup",
        "ecs:AuthorizeSecurityGroupEgress",
        "ecs:AuthorizeSecurityGroup",
        "ecs:CreateSnapshot",
        "ecs:AttachDisk",
        "ecs:DetachDisk",
        "ecs:DescribeDisks",
        "ecs:CreateDisk",
        "ecs:DeleteDisk",
        "ecs:CreateNetworkInterface",
        "ecs:DescribeNetworkInterfaces",
        "ecs:AttachNetworkInterface",
        "ecs:DetachNetworkInterface",
        "ecs:DeleteNetworkInterface",
        "ecs:DescribeInstanceAttribute"
      ],
      "Resource": "*",
      "Effect": "Allow"
    },
    {
      "Action": [
        "vpc:DescribeVpcs",
        "vpc:DescribeVSwitches",
        "vpc:AllocateEipAddress",
        "vpc:AssociateEipAddress",
        "vpc:UnassociateEipAddress",
        "vpc:DescribeEipAddresses",
        "vpc:ReleaseEipAddress",
        "vpc:CreateVpc",
        "vpc:DeleteVpc",
        "vpc:DescribeVpcs",
        "vpc:CreateVSwitch",
        "vpc:DeleteVSwitch",
        "vpc:DescribeVSwitches",
        "vpc:CreateRouteTable",
        "vpc:DeleteRouteTable",
        "vpc:DescribeRouteTables",
        "vpc:CreateNatGateway",
        "vpc:DeleteNatGateway",
        "vpc:DescribeNatGateways",
        "vpc:CreateSnatEntry",
        "vpc:DeleteSnatEntry",
        "vpc:DescribeSnatTableEntries"
      ],
      "Resource": "*",
      "Effect": "Allow"
    }
  ]
}

Run the following command to generate encrypted strings for the AccessKey pair.

echo -n "AKxxxxxxxxxxxxxxx" | base64
echo -n "SKxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx" | base64

Use the following YAML template to create a Secret named my-secret.

apiVersion: v1
kind: Secret
metadata:
  name: my-secret
  namespace: default
type: Opaque
data:
  ALICLOUD_ACCESS_KEY: TFRxxxxxxxxxxxxxRTkx      // The Base64-encoded string in the previous substep.
  ALICLOUD_SECRET_KEY: a0zxxxxxxxxxxxxxx2UThl

Create a YAML file named build.yaml and add the following content to the file.

Configure variables to run the Job. The ECS instance of the specified instance type created from the base image is used to build the custom image. The instance type is specified by using the instance_type parameter and the base image is specified by using the source_image parameter. The ECS instance belongs to the Alibaba Cloud account to which the AccessKey pair belongs. The system then runs the configurations of the provisioner and pushes the image built by the ECS instance to the specified region as a custom image. The custom image also belongs to the Alibaba Cloud account to which the AccessKey pair belongs.

YAML template

apiVersion: batch/v1
kind: Job
metadata:
  name: image-builder
  namespace: default
spec:
  template:
    metadata:
      name: image-builder
    spec:
  template:
    metadata:
      name: image-builder
    spec:
      containers:
        - name: image-builder
          image: "registry-cn-hangzhou-vpc.ack.aliyuncs.com/acs/image-builder:v3.3"
          imagePullPolicy: Always
        env:            
         - name: ALICLOUD_ACCESS_KEY              
         	 valueFrom:                
        	   secretKeyRef:                  
       		     name: my-secret                  
               key: ALICLOUD_ACCESS_KEY            
         - name: ALICLOUD_SECRET_KEY              
           valueFrom:                
             secretKeyRef:                  
               name: my-secret                  
               key: ALICLOUD_SECRET_KEY            
         - name: ALICLOUD_REGION              
           value: cn-hangzhou   
          command: ["packer"]
          args:  ["build","/config/ack.json"]
          volumeMounts:
            - name: config
              mountPath: /config
      volumes:
        - name: config
          configMap:
            name: build-config
            items:
              - key: ack.json
                path: ack.json
      restartPolicy: Never

Run the following command to deploy the Job and start to build the image:
```
kubectl apply -f build.yaml
```

Step 3: (Optional) View the image building log

A log is generated during the image building process. The log records all image building operations, including checking parameters, creating temporary resources, preinstalling software, creating target resources, and releasing temporary resources. To view the image building log, perform the following steps:

Log on to the ACK console. In the left-side navigation pane, click Clusters.
On the Clusters page, find the cluster that you want to manage and click its name. In the left-side pane, choose Workloads > Jobs.
On the Jobs page, find the Job that you created and click Details in the Actions column.
On the Job details page, click the Logs tab to check the image building log.

Provisioner configuration

A provisioner is a component used to install and configure software in a running operating system before the operating system is packaged into an OS image. A provisioner is often used to install software in images in the following scenarios:

Install software.
Patch kernels.
Create users.
Download application code.
Build a custom Alibaba Cloud Linux 3 image.

Execute shell scripts

  "provisioners": [{
      "type": "shell",
      "script": "script.sh"
  }]

Execute orchestration scripts by using Ansible

  "provisioners": [
    {
    "type": "ansible",
    "playbook_file": "./playbook.yml"
    }
  ]

Install the CPFS client

The installation of Cloud Paralleled File System (CPFS) requires multiple installation packages, some of which involve real-time compilation and may require an additional period of time to install. The use of a custom image can greatly reduce the cost of installing the CPFS client on a large number of nodes. The following sample code shows a configuration example.

YAML template

    {
      "variables": {
        "region": "{{env `ALICLOUD_REGION`}}",
        "image_name": "ack-custom_image",
        "source_image": "centos_7_04_64_20G_alibase_201701015.vhd",
        "access_key": "{{env `ALICLOUD_ACCESS_KEY`}}",
        "instance_type": "ecs.c6.xlarge",
        "secret_key": "{{env `ALICLOUD_SECRET_KEY`}}"
      },
    "builders": [
        {
          "type": "alicloud-ecs",
          "access_key": "{{user `access_key`}}",
          "secret_key": "{{user `secret_key`}}",
          "region": "{{user `region`}}",
          "image_name": "{{user `image_name`}}",
          "source_image": "{{user `source_image`}}",
          "ssh_username": "root",
          "instance_type": "{{user `instance_type`}}",
          "skip_image_validation": "true",
          "io_optimized": "true"
        }
      ],
   "provisioners": [{
        "type": "shell",
        "inline": [
            "cd $HOME",
            "wget https://cpfs-client.oss-cn-beijing.aliyuncs.com/kernel/kernel-devel-`uname -r`.rpm",
            "rpm -ivh --replacefiles kernel-devel-`uname -r`.rpm"
        ]
      }]

Build an ARM-based image

YAML template

{
      "variables": {
        "region": "{{env `ALICLOUD_REGION`}}",
        "image_name": "ack-custom_image",
        "source_image": "aliyun_3_arm64_20G_alibase_20240528.vhd",
        "instance_type": "ecs.r8y.xlarge",   # Specify an instance type that uses the ARM architecture. 
        "access_key": "{{env `ALICLOUD_ACCESS_KEY`}}",
        "secret_key": "{{env `ALICLOUD_SECRET_KEY`}}"
      },
    "builders": [
        {
          "type": "alicloud-ecs",
          "access_key": "{{user `access_key`}}",
          "secret_key": "{{user `secret_key`}}",
          "region": "{{user `region`}}",
          "image_name": "{{user `image_name`}}",
          "source_image": "{{user `source_image`}}",
          "instance_type": "{{user `instance_type`}}",
          "ssh_username": "root",
          "skip_image_validation": "true",
          "io_optimized": "true"
        }
      ],
   "provisioners": [
        {
            "type": "file",
            "source": "scripts/ack-optimized-os-linux3-all.sh",
            "destination": "/root/"
        },
        {
            "type": "shell",
            "inline": [
                "export RUNTIME=containerd",
                "export SKIP_SECURITY_FIX=true",
                "export KUBE_VERSION=1.28.9-aliyun.1",
                "export OS_ARCH=arm64",
                "bash /root/ack-optimized-os-linux3-all.sh"
            ]
        }
      ]
    }

Customize the OS image of a GPU-accelerated node

Important

You cannot deploy images with GPU drivers preinstalled on CPU-accelerated nodes.

YAML template

{
      "variables": {
        "region": "{{env `ALICLOUD_REGION`}}",
        "image_name": "ack-custom_image",
        "source_image": "aliyun_2_1903_x64_20G_alibase_20221102.vhd",
        "instance_type": "ecs.gn6i-c4g1.xlarge",   # Specify the type of the GPU-accelerated instance where the GPU driver will be preinstalled. 
        "access_key": "{{env `ALICLOUD_ACCESS_KEY`}}",
        "secret_key": "{{env `ALICLOUD_SECRET_KEY`}}"
      },
    "builders": [
        {
          "type": "alicloud-ecs",
          "access_key": "{{user `access_key`}}",
          "secret_key": "{{user `secret_key`}}",
          "region": "{{user `region`}}",
          "image_name": "{{user `image_name`}}",
          "source_image": "{{user `source_image`}}",
          "instance_type": "{{user `instance_type`}}",
          "ssh_username": "root",
          "skip_image_validation": "true",
          "io_optimized": "true"
        }
      ],
   "provisioners": [
        {
            "type": "file",
            "source": "scripts/ack-optimized-os-all.sh",
            "destination": "/root/"
        },
        {
            "type": "shell",
            "inline": [
                "export RUNTIME=containerd",
                "export SKIP_SECURITY_FIX=true",
                "export PRESET_GPU=true",          # Set PRESET_GPU to true if you need to preinstall the GPU driver. Otherwise, leave the parameter empty or set it to false. 
                "export NVIDIA_DRIVER_VERSION=510.47.03",         # Specify the GPU driver version. If you leave this parameter empty, the 460.91.03 version is installed. 
                "export KUBE_VERSION=1.22.3-aliyun.1",
                "export OS_ARCH=amd64",
                "bash /root/ack-optimized-os-all.sh"
            ]
        }
      ]
    }

Add the application image to the system image

YAML template

{
      "variables": {
        "image_name": "ack-custom_image",
        "source_image": "aliyun_3_x64_20G_alibase_20240528.vhd",
        "instance_type": "ecs.c6.xlarge",
        "access_key": "{{env `ALICLOUD_ACCESS_KEY`}}",
        "region": "{{env `ALICLOUD_REGION`}}",
        "secret_key": "{{env `ALICLOUD_SECRET_KEY`}}"
      },
    "builders": [
        {
          "type": "alicloud-ecs",
          "access_key": "{{user `access_key`}}",
          "secret_key": "{{user `secret_key`}}",
          "region": "{{user `region`}}",
          "image_name": "{{user `image_name`}}",
          "source_image": "{{user `source_image`}}",
          "instance_type": "{{user `instance_type`}}",
          "ssh_username": "root",
          "skip_image_validation": "true",
          "io_optimized": "true"
        }
      ],
   "provisioners": [
        {
            "type": "file",
            "source": "scripts/ack-optimized-os-linux3-all.sh",
            "destination": "/root/"
        },
        {
            "type": "shell",
            "inline": [
                "export RUNTIME=containerd",
                "export SKIP_SECURITY_FIX=true",
                "export KUBE_VERSION=1.30.1-aliyun.1",
                "export OS_ARCH=amd64",
                "bash /root/ack-optimized-os-linux3-all.sh",
                "ctr -n k8s.io i pull registry-cn-hangzhou-vpc.ack.aliyuncs.com/acs/pause:3.9"        # Add the application image to the system image. 
            ]
        }
      ]
    }

Disk initialization occurs when you add an ECS instance with a mounted data disk to a node pool, which results in the removal of any pre-stored application images. To mount a data disk when you create an ECS instance from a custom image, you can generate a data disk snapshot during the custom image creation process to ensure that the application image is preserved.

{
      "variables": {
        "image_name": "ack-custom_image",
        "source_image": "aliyun_3_x64_20G_alibase_20240528.vhd",
        "instance_type": "ecs.c6.xlarge",
        "access_key": "{{env `ALICLOUD_ACCESS_KEY`}}",
        "region": "{{env `ALICLOUD_REGION`}}",
        "secret_key": "{{env `ALICLOUD_SECRET_KEY`}}"
      },
    "builders": [
        {
          "type": "alicloud-ecs",
          "system_disk_mapping": {    
                    "disk_size": 120,
                    "disk_category": "cloud_essd"
                    },
          "image_disk_mappings": {
                    "disk_size": 40,
                    "disk_category": "cloud_auto"
                    },     # Configure a data disk when you create the custom image, and a snapshot of the data disk is automatically generated after the image is created.
          "access_key": "{{user `access_key`}}",
          "secret_key": "{{user `secret_key`}}",
          "region": "{{user `region`}}",
          "image_name": "{{user `image_name`}}",
          "source_image": "{{user `source_image`}}",
          "instance_type": "{{user `instance_type`}}",
          "ssh_username": "root",
          "skip_image_validation": "true",
          "io_optimized": "true"
        }
      ],
   "provisioners": [
        {
            "type": "file",
            "source": "scripts/ack-optimized-os-linux3-all.sh",
            "destination": "/root/"
        },
        {
            "type": "shell",
            "inline": [
                "export RUNTIME=containerd",
                "export SKIP_SECURITY_FIX=true",
                "export KUBE_VERSION=1.30.1-aliyun.1",
                "export OS_ARCH=amd64",
                "export MOUNT_RUNTIME_DATADISK=true",     # Mount the file path of the container runtime to the data disk.
                "bash /root/ack-optimized-os-linux3-all.sh",
                "ctr -n k8s.io i pull registry-cn-hangzhou-vpc.ack.aliyuncs.com/acs/pause:3.9",        # Add the application image to the system image.
                "mv /var/lib/containerd /var/lib/container/containerd"       # Move the image file to the data disk.
            ]
        }
      ]
    }

When you configure the node pool, you can set up a custom image that includes data disk snapshots, and the system will automatically associate the corresponding data disk snapshots.

Pull an image from a private image repository when the container runtime is Docker

docker login <Image address> -u user -p password
docker pull nginx

Pull an image from a private image repository when the container runtime is containerd

ctr -n k8s.io i pull --user=username:password nginx

Pull an image from a private repository after the custom image is built

Run the following docker login command on a Linux server that has Docker installed to generate a certificate:
```
docker login --username=zhongwei.***@aliyun-test.com --password xxxxxxxxxx registry.cn-beijing.aliyuncs.com
```
After the docker login command succeeds, a certificate named config.json is created in the /root/.docker directory.

Create a ConfigMap based on the certificate file named config.json.

apiVersion: v1
kind: ConfigMap
metadata:
  name: docker-config
data:
  config.json: |-

    {
        "auths": {
                "registry.cn-beijing.aliyuncs.com": {
                        "auth": "xxxxxxxxxxxxxx"
                }
        },
        "HttpHeaders": {
                "User-Agent": "Docker-Client/19.03.15 (linux)"
        }

    }

Modify the YAML template of the Job to mount the ConfigMap to the pod.

YAML template

apiVersion: batch/v1
kind: Job
metadata:
  name: image-builder
  namespace: default
spec:
  template:
    metadata:
      name: image-builder
    spec:
      containers:
        - name: image-builder
          image: "registry.cn-hangzhou.aliyuncs.com/acs/image-builder:v2.9"
          imagePullPolicy: Always
          env:
            - name: ALICLOUD_ACCESS_KEY
              value: xxxxxxxxxxxxxx
            - name: ALICLOUD_SECRET_KEY
              value: xxxxxxxxxxxxx
            - name: ALICLOUD_REGION
              value: cn-heyuan
          command: ["packer"]
          args:  ["build","/config/ack.json"]
          volumeMounts:
            - name: config
              mountPath: /config
            - name: docker
              mountPath: /dockerconfig
      volumes:
        - name: config
          configMap:
            name: build-config
            items:
              - key: ack.json
                path: ack.json
        - name: docker
          configMap:
            name: docker-config
            items:
              - key: config.json
                path: config.json
      restartPolicy: Never

Add the content in the following figure to the build-config ConfigMap.

YAML template

apiVersion: v1
kind: ConfigMap
metadata:
  name: build-config
data:
  ack.json: |-

    {
      "variables": {
        "image_name": "ack-optimized_image-1.20-{{timestamp}}",
        "source_image": "aliyun_2_1903_x64_20G_alibase_20221102.vhd",
        "instance_type": "ecs.c6.xlarge",
        "region": "{{env `ALICLOUD_REGION`}}",
        "access_key": "{{env `ALICLOUD_ACCESS_KEY`}}",
        "secret_key": "{{env `ALICLOUD_SECRET_KEY`}}"
      },
      "builders": [
        {
          "type": "alicloud-ecs",
          "access_key": "{{user `access_key`}}",
          "secret_key": "{{user `secret_key`}}",
          "region": "{{user `region`}}",
          "image_name": "{{user `image_name`}}",
          "source_image": "{{user `source_image`}}",
          "ssh_username": "root",
          "instance_type": "{{user `instance_type`}}",
          "skip_image_validation": "true",
          "io_optimized": "true"
        }
      ],
      "provisioners": [{
       "type": "file",
       "source": "scripts/ack-optimized-os-all.sh",
       "destination": "/root/"
        },
        {
       "type": "file",
       "source": "dockerconfig/config.json",
       "destination": "/root/"
        },
        {
       "type": "shell",
       "inline": [
         "export OS_ARCH=amd64",
         "export RUNTIME=docker",
         "export SKIP_SECURITY_FIX=true",
         "export KUBE_VERSION=1.22.15-aliyun.1",
         "bash /root/ack-optimized-os-all.sh",
         "mkdir -p /root/.docker",
         "cp /root/config.json /root/.docker",
         "docker pull registry.cn-beijing.aliyuncs.com/ringtail/kruise-game:0.1"

      ]
      }]
    }

Execute the Job.

Specify the maximum numbers of concurrent uploads and downloads for the image

Log on to the ACK console. In the left-side navigation pane, click Clusters.
On the Clusters page, find the cluster that you want to manage and click its name. In the left-side pane, choose Nodes > Node Pools.
Find the node pool that you want to manage and click its name. Click the Overview tab. In the Node Pool Information section, click the hyperlink next to the Auto Scaling Group field.
On the page that appears, click the Instance Configuration Sources tab. Find the scaling configuration that you want to manage, click Edit in the Actions column, and click OK.
On the Modify Scaling Configuration page, modify the parameters and click Advanced Settings to show the advanced settings. Record the data in the Instance User Data box. Decode the data in the Instance User Data box by using Base64.

After you decode the data, append the following code to the end of the decoded data.

yum install -y jq
echo "$jq '. += {"max-concurrent-downloads": 20,"max-concurrent-uploads": 20}' /etc/docker/daemon.json" > /etc/docker/daemon.json
service docker restart

Encode the modified data in Base64 and overwrite the original data in the Instance User Data box with the modified data. Click Modify. In the dialog box that appears, click Modify.

Build a custom Alibaba Cloud Linux 3 image

YAML template

apiVersion: v1
kind: ConfigMap
metadata:
  name: build-config
data:
  ack.json: |-
    
    {
      "variables": {
        "image_name": "ack-optimized_image-1.22-{{timestamp}}",
        "source_image":"aliyun_3_x64_20G_alibase_20230110.vhd",  # The base image for Alibaba Cloud Linux 3. 
        "instance_type": "ecs.c6.xlarge",
        "region": "{{env `ALICLOUD_REGION`}}",
        "access_key": "{{env `ALICLOUD_ACCESS_KEY`}}",
        "secret_key": "{{env `ALICLOUD_SECRET_KEY`}}",
      },
      "builders": [
        {
          "type": "alicloud-ecs",
          "access_key": "{{user `access_key`}}",
          "secret_key": "{{user `secret_key`}}",
          "region": "{{user `region`}}",
          "image_name": "{{user `image_name`}}",
          "source_image": "{{user `source_image`}}",
          "ssh_username": "root",  
          "instance_type": "{{user `instance_type`}}",
          "skip_image_validation": "true",
          "io_optimized": "true"
        }
      ],
      "provisioners": [{
       "type": "file",
       "source": "scripts/ack-optimized-os-linux3-all.sh",
       "destination": "/root/"
        },
        {
       "type": "shell",
       "inline": [
         "export RUNTIME=containerd",
         "export SKIP_SECURITY_FIX=true",
         "export OS_ARCH=amd64",
         "export KUBE_VERSION=1.22.3-aliyun.1",
         "bash /root/ack-optimized-os-linux3-all.sh",
      ]
      }]
    }

Build a custom Red Hat Enterprise Linux 9 (RHEL 9) image

YAML template

apiVersion: v1
kind: ConfigMap
metadata:
  name: build-config
data:
  ack.json: |-
    
    {
      "variables": {
        "image_name": "ack-optimized_image-1.26-{{timestamp}}",
        "source_image": "m-bp1c7zuf8mcabc99babc",       # The base image for RHEL 9. 
        "instance_type": "ecs.c6.xlarge",
        "region": "{{env `ALICLOUD_REGION`}}",
        "access_key": "{{env `ALICLOUD_ACCESS_KEY`}}",
        "secret_key": "{{env `ALICLOUD_SECRET_KEY`}}",
        "runtime": "{{env `RUNTIME`}}",
        "skip_secrutiy_fix": "{{env `SKIP_SECURITY_FIX`}}"
      },
      "builders": [
        {
          "type": "alicloud-ecs",
          "access_key": "{{user `access_key`}}",
          "secret_key": "{{user `secret_key`}}",
          "region": "{{user `region`}}",
          "image_name": "{{user `image_name`}}",
          "source_image": "{{user `source_image`}}",
          "ssh_username": "root",
          # "vpc_id": "",
          # "vswitch_id": "",
          # "security_group_id": "",      
          "instance_type": "{{user `instance_type`}}",
          "skip_image_validation": "true",
          "io_optimized": "true"
        }
      ],
      "provisioners": [{
       "type": "file",
       "source": "scripts/ack-optimized-os-rhel9-all.sh",
       "destination": "/root/"
        },
        {
       "type": "shell",
       "inline": [
         "export RUNTIME=containerd",
         "export SKIP_SECURITY_FIX=true",
         "export OS_ARCH=amd64",
         "export KUBE_VERSION=1.26.3-aliyun.1",
         "bash /root/ack-optimized-os-rhel9-all.sh"
      ]
      }]
    }

What to do next

After you create a custom image by using Alicloud Image Builder, you can create an elastic node pool based on the custom image to quickly add nodes to the cluster. For more information about how to create an elastic node pool, see Enable node auto scaling.
After a custom image is created, you can use the custom image to create an ACK cluster. For more information, see How do I create a custom image based on an existing ECS instance and use it to create nodes?