随着云原生时代的到来，用户应用、业务上云的需求也越来越多，不同的业务场景对容器平台的需求也不尽相同，其中一个非常重要的需求就是使用自定义镜像创建ACK集群。
ACK支持用户使用自定义镜像创建Kubernetes集群，但用户在制作打包自定义镜像时，往往会遇到以下痛点：
（1）人工操作步骤，效率低
（2）镜像变更历史记录缺失，不便于故障定位
（3）无法对自定义镜像进行校验并判断是否符合ACK集群节点要求
基于以上痛点，我们开源了ack-image-builder项目帮助用户快速制作符合ACK集群节点要求的自定义镜像。
ack-image-builder项目基于开源工具HashiCorp Packer，提供默认配置模板和校验脚本。
使用ack-image-builder项目创建ACK集群自定义节点镜像的步骤如下：
1. 安装Packer
从官方下载页面选择操作系统对应的软件版本，并按照安装说明文档安装和验证packer。
$ packer version
Packer v1.4.1
说明packer已安装成功。
2. 定义Packer模板
使用Packer创建自定义镜像时，需要创建一个JSON格式的模板文件。在该模板文件中，您需要指定创建自定义镜像的Alicloud Image Builder（生成器）和Provisioners（配置器）。
{
"variables": {
"region": "cn-hangzhou",
"image_name": "test_image{{timestamp}}",
"source_image": "centos_7_06_64_20G_alibase_20190711.vhd",
"instance_type": "ecs.n1.large",
"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`}}",
"io_optimized": "true"
}
],
"provisioners": [
{
"type": "shell",
"scripts": [
"scripts/updateKernel.sh",
"scripts/reboot.sh",
"scripts/cleanUpKerneles.sh",
"config/default.sh",
"scripts/updateDNS.sh",
"scripts/verify.sh"
],
"expect_disconnect": true
}
]
}
3. 创建子账号并生成AK
制作自定义镜像的权限要求较大，一般建议用户创建子账户并授权Packer需要的对应RAM Policy,并创建AK。
4. 导入AK信息并制作自定义镜像
导入AK：
export ALICLOUD_ACCESS_KEY=XXXXXX
export ALICLOUD_SECRET_KEY=XXXXXX
制作自定义镜像：
$ packer build alicloud.json
alicloud-ecs output will be in this color.
==> alicloud-ecs: Prevalidating source region and copied regions...
==> alicloud-ecs: Prevalidating image name...
alicloud-ecs: Found image ID: centos_7_06_64_20G_alibase_20190711.vhd
==> alicloud-ecs: Creating temporary keypair: xxxxxx
==> alicloud-ecs: Creating vpc...
alicloud-ecs: Created vpc: xxxxxx
==> alicloud-ecs: Creating vswitch...
alicloud-ecs: Created vswitch: xxxxxx
==> alicloud-ecs: Creating security group...
alicloud-ecs: Created security group: xxxxxx
==> alicloud-ecs: Creating instance...
alicloud-ecs: Created instance: xxxxxx
==> alicloud-ecs: Allocating eip...
alicloud-ecs: Allocated eip: xxxxxx
alicloud-ecs: Attach keypair xxxxxx to instance: xxxxxx
==> alicloud-ecs: Starting instance: xxxxxx
==> alicloud-ecs: Using ssh communicator to connect: 47.111.127.54
==> alicloud-ecs: Waiting for SSH to become available...
==> alicloud-ecs: Connected to SSH!
==> alicloud-ecs: Provisioning with shell script: scripts/verify.sh
alicloud-ecs: [20190726 11:04:10]: Check if kernel version >= 3.10. Verify Passed!
alicloud-ecs: [20190726 11:04:10]: Check if systemd version >= 219. Verify Passed!
alicloud-ecs: [20190726 11:04:10]: Check if sshd is running and listen on port 22. Verify Passed!
alicloud-ecs: [20190726 11:04:10]: Check if cloud-init is installed. Verify Passed!
alicloud-ecs: [20190726 11:04:10]: Check if wget is installed. Verify Passed!
alicloud-ecs: [20190726 11:04:10]: Check if curl is installed. Verify Passed!
alicloud-ecs: [20190726 11:04:10]: Check if kubeadm is cleaned up. Verify Passed!
alicloud-ecs: [20190726 11:04:10]: Check if kubelet is cleaned up. Verify Passed!
alicloud-ecs: [20190726 11:04:10]: Check if kubectl is cleaned up. Verify Passed!
alicloud-ecs: [20190726 11:04:10]: Check if kubernetes-cni is cleaned up. Verify Passed!
==> alicloud-ecs: Stopping instance: xxxxxx
==> alicloud-ecs: Waiting instance stopped: xxxxxx
==> alicloud-ecs: Creating image: test_image1564110199
alicloud-ecs: Detach keypair xxxxxx from instance: xxxxxxx
==> alicloud-ecs: Cleaning up 'EIP'
==> alicloud-ecs: Cleaning up 'instance'
==> alicloud-ecs: Cleaning up 'security group'
==> alicloud-ecs: Cleaning up 'vSwitch'
==> alicloud-ecs: Cleaning up 'VPC'
==> alicloud-ecs: Deleting temporary keypair...
Build 'alicloud-ecs' finished.
==> Builds finished. The artifacts of successful builds are:
--> alicloud-ecs: Alicloud images were created:
cn-hangzhou: m-bp1aifbnupnaktj00q7s
其中scripts/verify.sh为对检查项的校验部分。
5. 使用自定义镜像创建ACK集群
登录容器服务控制台，选择创建Kubernetes 专有版集群， 配置集群创建需要的相关基础信息后，点开显示高级选项并选择自定义镜像进行集群创建。
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