SDK for Ceph Object Classes

Ceph can be extended by creating shared object classes called Ceph Object Classes. The existing framework to build these object classes has dependencies on the internal functionality of Ceph, which restricts users to build object classes within the tree. The aim of this project is to create an independent object class interface, which can be used to build object classes outside the Ceph tree. This allows us to have two types of object classes, 1) those that have in-tree dependencies and reside in the tree and 2) those that can make use of the Ceph Object Class SDK framework and can be built outside of the Ceph tree because they do not depend on any internal implementation of Ceph. This project decouples object class development from Ceph and encourages creation and distribution of object classes as packages.

In order to demonstrate the use of this framework, we have provided an example called cls_sdk, which is a very simple object class that makes use of the SDK framework. This object class resides in the src/cls directory.

Installing objclass.h

The object class interface that enables out-of-tree development of object classes resides in src/include/rados/ and gets installed with Ceph installation. After running make install, you should be able to see it in <prefix>/include/rados.

ls /usr/local/include/rados

Using the SDK example

The cls_sdk object class resides in src/cls/sdk/. This gets built and loaded into Ceph, with the Ceph build process. You can run the ceph_test_cls_sdk unittest, which resides in src/test/cls_sdk/, to test this class.