制作ACK集群自定义节点镜像的正确姿势

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
    }
  ]
}

参数	描述
access_key	您的AccessKeyID
secret_key	您的AccessKeySecret
region	创建自定义镜像时使用临时资源的地域
image_name	自定义镜像的名称
source_image	基础镜像的名称，可以从阿里云公共镜像列表获得
instance_type	创建自定义镜像时生成的临时实例的类型
provisioners	创建自定义镜像时使用的 Packer 配置器 类型

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。

本文作者：流生

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