oslo（OpenStack Common Libraries） 是
python lib 库。
通用缓存 cache 库
Cache storage for OpenStack projects.
The oslo concurrency library has utilities for safely running multi-thread, multi-process applications using locking mechanisms and for running external processes.
The Oslo context library has helpers to maintain useful information about a request context. The request context is usually populated in the WSGI pipeline and used by various modules such as logging.
An OpenStack library for parsing configuration options from the command line and configuration files.
The oslo.db (database) handling library, provides database connectivity to different database backends and various other helper utils.
The oslo.i18n library contain utilities for working with internationalization (i18n) features, especially translation for text strings in an application or library.
The oslo.log (logging) configuration library provides standardized configuration for all openstack projects. It also provides custom formatters, handlers and support for context specific logging (like resource id’s etc).
RPC 的库，支持各种不同消息队列，常用的消息队列是 rabbitmq，参考：
The Oslo messaging API supports RPC and notifications over a number of different messaging transports.
Middlewares can be configured in multiple fashion depending of the application needs.
OpenStack 基于 RBAC 控制角色权限库
An OpenStack library providing support for RBAC policy enforcement across all OpenStack services.
OpenStack 实现的普通用户执行超级权限的库，可以让命令行或 python lib 实现超权。
oslo.privsep is an OpenStack library for privilege separation.
It helps applications perform actions which require more or less privileges than they were started with in a safe, easy to code and easy to use manner. For more information on why this is generally a good idea please read over the principle of least privilege and the specification which created this library.
oslo.rootwrap allows fine-grained filtering of shell commands to run as root from OpenStack services.
将 OpenStack 对象序列化为可传递或存储字符串
The oslo serialization library provides support for representing objects in transmittable and storable formats, such as JSON and MessagePack.
OpenStack daemon 程序库
oslo.service provides a framework for defining new long-running services using the patterns established by other OpenStack applications. It also includes utilities long-running applications might need for working with SSL or WSGI, performing periodic operations, interacting with systemd, etc.
Tools is a helper library that provides various low-level utility modules/code.
The Oslo utils library provides support for common utility type functions, such as encoding, exception handling, string manipulation, and time handling.
The oslo.versionedobjects library provides a generic versioned object model that is RPC-friendly, with inbuilt serialization, field typing, and remotable method calls. It can be used to define a data model within a project independent of external APIs or database schema for the purposes of providing upgrade compatibility across distributed services.