What are best practices for implementing Packer?

    {
      "builders": [
        {
          "type": "amazon-ebs",
          "access_key": "YOUR_AWS_ACCESS_KEY",
          "secret_key": "YOUR_AWS_SECRET_KEY",
          "region": "us-east-1",
          "source_ami": "ami-abc123456",
          "instance_type": "t2.micro",
          "ssh_username": "ec2-user",
          "ami_name": "example-ami {{timestamp}}"
        }
      ],
      "provisioners": [
        {
          "type": "shell",
          "inline": [
            "sudo yum update -y",
            "sudo yum install -y httpd",
            "sudo systemctl start httpd",
            "sudo systemctl enable httpd"
          ]
        }
      ]
    }