基于go-ceph创建CEPH块设备及快照

一、代码执行前准备

1、系统中安装了CEPH集群

2、GOPATH目录下存在src/github.com/noahdesu/go-ceph代码库

3、在ubuntu 14.04下还需apt-get librados-dev和librbd-dev两个包

二、代码示例

package main 

import (
	"fmt"
	"github.com/noahdesu/go-ceph/rados"
	"github.com/noahdesu/go-ceph/rbd"
)

const (
	DefaultRadosConfigFile = "/etc/ceph/ceph.conf"
	DefaultBaseImageSize = 10 * 1024 * 1024 * 1024
	DefaultPoolName = "rbd"
)

func main() {
	// connect to the cluster
	conn,_ := rados.NewConn()
	if err := conn.ReadConfigFile(DefaultRadosConfigFile); err != nil {
		fmt.Printf("Rbd read config failed: %v",err)
		return
	}
	if err := conn.Connect(); err != nil {
		fmt.Printf("Rbd connect failed: %v",err)
		return
	}
	
	// connect to the pool
	ioctx,err := conn.OpenIOContext(DefaultPoolName)
	if err != nil {
		fmt.Printf("Rbd open pool failed: %v",err)
		return
	}

	// create base image
	baseImageName := "test"
	_,err = rbd.Create(ioctx,baseImageName,DefaultBaseImageSize,rbd.RbdFeatureLayering)
	if err != nil {
		fmt.Printf("Rbd create image failed: %v",err)
		return
	}

	img := rbd.GetImage(ioctx,baseImageName)

	// we should open base image first
	if err := img.Open(); err != nil {
		fmt.Printf("Rbd open image  failed: %v",err)
		return
	}

	defer img.Close()
	
	// create snapshot
	snapName := "test-snap"
	snapshot,err := img.CreateSnapshot(snapName)
	if err != nil {
		fmt.Printf("Rbd create snapshot failed: %v",err)
		return
	}

	// protect snapshot 
	if err := snapshot.Protect(); err != nil {
		fmt.Printf("Rbd create snapshot failed: %v",err)
		return 
	}

	// make a clone image based on the snap shot
	cloneImageName := "clone-test"
	_,err = img.Clone(snapName,ioctx,cloneImageName,rbd.RbdFeatureLayering)
	if err != nil {
		fmt.Printf("Rbd clone snapshot failed: %v",err)
		return 
	}
	
	return
}

　　

三、最终会生成一个名为"test"的基础image，以及一个基于"test"的名为"test-snap"的snapshot，最后还有一个基于快照"test-snap"的clone。

　　注：在创建"test"时，size参数不能太小，否则在创建快照的时候会产生错误。