openstack的镜像管理模块glance，采用了一个名为image_properties的表来记录各镜像的属性信息，例如该某个镜像使用的系统架构（architecture）、操作系统的版本（os_version）等。

该表采用了一种key－value的方式来记录这些属性，常见的key有：kernel_id、ramdisk_id、instance_uuid、architecture、os_distro、os_version等

而文件schema-image.json就是对这些字段进行解释说明的，如下：

{
    "kernel_id": {
        "type": "string",
        "pattern": "^([0-9a-fA-F]){8}-([0-9a-fA-F]){4}-([0-9a-fA-F]){4}-([0-9a-fA-F]){4}-([0-9a-fA-F]){12}$",
        "description": "ID of image stored in Glance that should be used as the kernel when booting an AMI-style image."
    },
    "ramdisk_id": {
        "type": "string",
        "pattern": "^([0-9a-fA-F]){8}-([0-9a-fA-F]){4}-([0-9a-fA-F]){4}-([0-9a-fA-F]){4}-([0-9a-fA-F]){12}$",
        "description": "ID of image stored in Glance that should be used as the ramdisk when booting an AMI-style image."
    },
    "instance_uuid": {
        "type": "string",
        "description": "ID of instance used to create this image."
    },
    "architecture": {
        "description": "Operating system architecture as specified in http://docs.openstack.org/trunk/openstack-compute/admin/content/adding-images.html",
        "type": "string"
    },
    "os_distro": {
        "description": "Common name of operating system distribution as specified in http://docs.openstack.org/trunk/openstack-compute/admin/content/adding-images.html",
        "type": "string"
    },
    "os_version": {
        "description": "Operating system version as specified by the distributor",
        "type": "string"
    }
}