Image service overview¶

The Image service (glance) enables users to discover, register, and retrieve virtual machine images. It offers a REST API that enables you to query virtual machine image metadata and retrieve an actual image. You can store virtual machine images made available through the Image service in a variety of locations, from simple file systems to object-storage systems like OpenStack Object Storage.

重要

For simplicity, this guide describes configuring the Image service to use the file back end, which uploads and stores in a directory on the controller node hosting the Image service. By default, this directory is /var/lib/glance/images/.

Before you proceed, ensure that the controller node has at least several gigabytes of space available in this directory. Keep in mind that since the file back end is often local to a controller node, it is not typically suitable for a multi-node glance deployment.

For information on requirements for other back ends, see Configuration Reference.

OpenStack镜像服务是IaaS的核心服务，如同 :ref:`get_started_conceptual_architecture`所示。它接受磁盘镜像或服务器镜像API请求，和来自终端用户或OpenStack计算组件的元数据定义。它也支持包括OpenStack对象存储在内的多种类型仓库上的磁盘镜像或服务器镜像存储。

大量周期性进程运行于OpenStack镜像服务上以支持缓存。同步复制（Replication）服务保证集群中的一致性和可用性。其它周期性进程包括auditors, updaters, 和 reapers。

OpenStack镜像服务包括以下组件：

glance-api: 接收镜像API的调用，诸如镜像发现、恢复、存储。
glance-registry: 存储、处理和恢复镜像的元数据，元数据包括项诸如大小和类型。

警告

glance-registry是私有内部服务，用于服务OpenStack Image服务。不要向用户暴露该服务
数据库: 存放镜像元数据，用户是可以依据个人喜好选择数据库的，多数的部署使用MySQL或SQLite。
镜像文件的存储仓库: Various repository types are supported including normal file systems (or any filesystem mounted on the glance-api controller node), Object Storage, RADOS block devices, VMware datastore, and HTTP. Note that some repositories will only support read-only usage.
元数据定义服务: 通用的API，是用于为厂商，管理员，服务，以及用户自定义元数据。这种元数据可用于不同的资源，例如镜像，工件，卷，配额以及集合。一个定义包括了新属性的键，描述，约束以及可以与之关联的资源的类型。

Image service overview

Contents

Image service overview¶

目录