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。