四、範例

Packer Template(sample.json)

{
  "variables": {
    "aws_access_key": "{{env `AWS_ACCESS_KEY_ID`}}",
    "aws_secret_key": "{{env `AWS_SECRET_ACCESS_KEY`}}",
    "region": "{{env `AWS_DEFAULT_REGION`}}"
  },
  "builders": [{
    "type": "amazon-ebs",
    "access_key": "{{user `aws_access_key`}}",
    "secret_key": "{{user `aws_secret_key`}}",
    "region": "{{user `region`}}",
    "source_ami_filter": {
      "filters": {
      "virtualization-type": "hvm",
      "name": "ubuntu/images/*ubuntu-xenial-16.04-amd64-server-*",
      "root-device-type": "ebs"
      },
      "owners": ["099720109477"],
      "most_recent": true
    },
    "instance_type": "t2.micro",
    "ssh_username": "ubuntu",
    "ami_name": "packer-example {{timestamp}}"
  }],
  "provisioners": [
    {
      "type": "shell",
      "inline": [
        "sleep 30",
        "sudo apt-get update",
        "sudo apt-get install -y redis-server"
      ]
    }
  ]
}

省略設定

前一天跟大家提到AWS credentials 授權(packer設定方式)，小編是使用「AWS credentials 檔案」(linux > $HOME/.aws/credentials)，所以在Template中以下區塊可以省略，留著也會套用$HOME/.aws/credentials，但如果你有設定環境變數的話(AWS_ACCESS_KEY_ID & AWS_SECRET_ACCESS_KEY & AWS_DEFAULT_REGION), 則會以「環境變數」為主!!!。

{
  "variables": {
    "aws_access_key": "{{env `AWS_ACCESS_KEY_ID`}}",
    "aws_secret_key": "{{env `AWS_SECRET_ACCESS_KEY`}}",
    "region": "{{env `AWS_DEFAULT_REGION`}}"
  },
  "builders": [{
    "access_key": "{{user `aws_access_key`}}",
    "secret_key": "{{user `aws_secret_key`}}",
    "region": "{{user `region`}}",
  }],
}

source_ami_filter

這個設定選項，會從aws public images當中根據你的條件產生「source_ami」(也可以直接設定source_ami)
至於filters當中可以使用的條件可以參考(AWS)DescribeImages

"source_ami_filter": {
  "filters": {
  "virtualization-type": "hvm",
  "name": "ubuntu/images/*ubuntu-xenial-16.04-amd64-server-*",
  "root-device-type": "ebs"
  },
  "owners": ["099720109477"],
  "most_recent": true
},

執行 packer build sample.json

在執行的過程中可以去AWS EC2 Console觀察變化

• packer output in linux
  

• instance change in AWS EC2 Console
  

• Security Groups change in AWS EC2 Console
  

• Your AMI created in AWS EC2 Console
  

待續...