Create and Import Local Images using Packer

Overview

Packer is a lightweight open-source tool for automatic image packaging launched by Hashicorp Company (for more details, refer to the previous document). Genesis Cloud now supports one-click importing of homemade local images into the Genesis Cloud cloud platform thanks to the integration of Packer.

Packer Official Download Page

For installing Packer

Open Source Repository Address

Feel free to contribute codes to Genesis Cloud Packer Builder

Image Import Example

Next, a CentOS image will be created and imported using Packer. It is shown below:

Packer first makes a RAW image using QEMU Builder , stored in a local directory specified by user, and then uses import Post-Processors to store the local image to a UFile specified by the user, and automatically imports it into the Genesis Cloud cloud platform.

Environment setup

Install Packer

Follow the official installation document to install Packer

Configure default User

Set keys TEST_PUBLIC_KEY, TEST_PRIVATE_ KEY and project ID TEST_PROJECT_ID as global environment variables (recommended), or specify public_key、 private_key、 project_id explicitly in the json file.

Install QEMU

Follow the official installation document , and you can use command lines to install it. MacOS: brew install qemu, CentOs: yum install qemu-kvm, Ubuntu: apt-get install qemu

Create a UFile bucket

Follow the official document

Write a JSON File

Let’s take the example of creating and importing a CentOS 6.10 custom image using QEMU on a macOS system. First, create a clean empty folder as the workspace, switch to this directory, and write a JSON specification file (e.g., local.json) as follows:


{"variables": {
  "test_public_key": "{{env `TEST_PUBLIC_KEY`}}",
  "test_private_key": "{{env `TEST_PRIVATE_KEY`}}",
  "test_project_id": "{{env `TEST_PROJECT_ID`}}",
  "disk_size": "4096",
  "iso_checksum": "0da4a1206e7642906e33c0f155d2f835",
  "iso_checksum_type": "md5",
  "iso_name": "CentOS-6.10-x86_64-minimal.iso",
  "ks_path": "centos-6.10/ks.cfg",
  "mirror": "http://mirrors.ustc.edu.cn/centos",
  "mirror_directory": "6.10/isos/x86_64",
  "template": "centos-6.10-x86_64"
},
  "builders":[
    {
      "type": "qemu",
      "boot_command": [
        "<tab> text ks=http://{{ .HTTPIP }}:{{ .HTTPPort }}/{{user `ks_path`}}<enter><wait>"
      ],
      "boot_wait": "10s",
      "disk_size": "{{user `disk_size`}}",
      "http_directory": "http",
      "iso_checksum": "{{user `iso_checksum`}}",
      "iso_checksum_type": "{{user `iso_checksum_type`}}",
      "iso_url": "{{user `mirror`}}/{{user `mirror_directory`}}/{{user `iso_name`}}",
      "output_directory": "packer-{{user `template`}}-qemu",
      "shutdown_command": "echo 'packer'|sudo -S shutdown -P now",
      "ssh_password": "test_packer",
      "ssh_port": 22,
      "ssh_username": "root",
      "ssh_timeout": "10000s",
      "vm_name": "{{ user `template` }}.raw",
      "net_device": "virtio-net",
      "disk_interface": "virtio",
      "format": "raw",
      "use_default_display": "false",
      "qemuargs": [
        ["-display", "cocoa"]
      ]
    }
  ],
  "post-processors":[
    {
      "type":"import",
      "public_key": "{{user `test_public_key`}}",
      "private_key": "{{user `test_private_key`}}",
      "project_id": "{{user `test_project_id`}}",
      "region":"cn-bj2",
      "ufile_bucket_name": "packer-test",
      "image_name": "packer_import_test",
      "image_os_type": "CentOS",
      "image_os_name": "CentOS 6.10 64bits",
      "format": "raw"
    }
  ]
}

This sets up a qemu Builder and an import Post-Processors , where the UFile bucket name and other information are configured.

Write Kickstart Files

Based on the http_directory and boot_command configured in the QEMU section of the above JSON file, a ./http/centos-6.10/ directory needs to be created in the JSON file’s directory to store the Kickstart file ks.cfg, as follows: (Kickstart reference document )


install
cdrom
lang en_US.UTF-8
keyboard us
network --bootproto=dhcp
rootpw test_packer
firewall --disabled
selinux --permissive
timezone UTC
unsupported_hardware
bootloader --location=mbr
text
skipx
zerombr
clearpart --all
autopart
auth --enableshadow --passalgo=sha512
firstboot --disabled
reboot

%packages --nobase --ignoremissing
sudo
gcc
make
%end

Execute the Command Line

By running the command packer build local.json, you can create and import a custom image in one click.