OpenStack实战篇之序章--KVM虚拟机监控

初识OpenStack两周，于它已没有初见时的神秘感，褪去层层面纱以后，渐识它的强大，决心以彼为刀剑，征战云计算的疆场，今夜，号角吹响，且奏序章。

    用OpenStack 建立虚拟实例后，须要对这些实例进行监控，本文所讲的是KVM环境下利用OpenStack集成的Libvirt API对虚拟机的CPU,内存，磁盘使用率以及网络上传下载速度进行监控。

    闲话少说，直接正题。

    1 对CPU的监控

Python 代码

import libvirt
import os
import time

conn=libvirt.open("qemu:///system")
if conn==None:
print "fail to connect hypervisor"
sys.exit(1)
try:
dom0=conn.lookupByID(85)#根据OpenStack建立的Instance ID获得相应的Domain对象
except:
print "fail to find the domain by ID"
sys.exit(1)

Pstart_time=time.time()   #取当前时间
Dstart_time=dom0.info()[4]#直接获取DomainInfo中的CPU时间信息
time.sleep(2)
Dstop_time=dom0.info()[4]
Pstop_time=time.time()
core_num=int(dom0.info()[3])#获取DomainIndo中的core数量信息

#CPU利用率计算公式-CPU时间差/时间间隔/1000000000/核的数量*100=CPU利用率
cpu_usage=(Dstart_time-Dstop_time)/(Pstart_time-Pstop_time)/1000000000/core_num*100
cpu_usage=cpu_usage if (cpu_usage>0) else 0.0
cpu_usage=cpu_usage if (cpu_usage<100) else 100.0
print cpu_usage

     

   2 对内存的监控

python代码

def get_memory(pid):#定义获取当前已使用的内存的函数
mem=0

#linux下 /proc/pid(进程ID）/smaps 下保存的是进程内存映像信息，比同一目录下的maps文件更详细些

for line in file('/proc/%d/smaps' % int(pid),'r'):
if re.findall('Private_',line):

  #统计Private内存信息量
mem+=int(re.findall('(\d+)',line)[0])
return mem

#根据实例名获取进程ID

pid=(os.popen("ps aux|grep "+dom0.name()+" | grep -v 'grep' | awk '{print $2}'").readlines()[0])
memstatus=get_memory(pid)
memusage='%.2f' % (int(memstatus)*100.0/int(dom0.info()[2]))
print memusage

验证方法： 能够SSH到相应的虚拟实例上，若是是Linux 系统能够用free -m指令查看内存使用率

 

   3 对磁盘的监控

   建立虚拟机应用实例时，会生成相应的XML文件来代表实例的信息

   def get_devices(dom,path,devs):#该函数用于获取XML中某节点的值

tree=ElementTree.fromstring(dom.XMLDesc(0))#将XML文件转换为XML树对象
devices=[]
for target in tree.findall(path):
dev=target.get(devs)
if not dev in devices:
devices.append(dev)
return devices

 

def get_blockStats(dom):#获取磁盘状态信息函数 包含磁盘读入的总比特数和写出的总比特数
block_status={}
disks=get_devices(dom,"devices/disk/target","dev")
for block in disks:
block_status[block]=dom.blockStats(block)
return block_status

 

block_status0={}
block_status1={}
block_status0=get_blockStats(dom0)
time.sleep(2)
block_status1=get_blockStats(dom0)
block_info=[]
for block in get_devices(dom0,"devices/disk/source","file"):
block_info.append(dom0.blockInfo(block,0))#获取磁盘信息 其中0为默认传入的参数
for domBlockInfo in block_info:
print "logical size in bytes :%s" % domBlockInfo[0]
print "highest allocated extent in bytes :%s" % domBlockInfo[1]
print "physical size in bytes :%s" % domBlockInfo[2]
print "disk usage :%s" % str(domBlockInfo[1]/1.0/domBlockInfo[0]*100)[:5]
for block in get_devices(dom0,"devices/disk/target","dev"):
print "rd_speed :%s" % str((block_status1[block][1]-block_status0[block][1])/2048)
print "wr_speed :%s" % str((block_status1[block][3]-block_status0[block][3])/2048)

验证方法： 能够SSH到相应的虚拟实例上，若是是Linux 系统能够用df -h指令查看磁盘使用率

 

    4 对网络的监控

def get_nicInfo(nics):#获取网络信息包括Receive的总比特数和Transmit的总比特数
net_status={}

#经过 cat /proc/net/dev 命令查看网络信息
for nic in nics:
net_status[nic]=[os.popen("cat /proc/net/dev |grep -w '"+nic+"' |awk '{print $10}'").readlines()[0][:-1],os.popen("cat /proc/net/dev |grep -w '"+nic+"' |awk '{print $2}'").readlines()[0][:-1]]
return net_status
net_status0={}
net_status1={}

#获取网卡名称
nics=get_devices(dom0,"devices/interface/target","dev")
net_status0=get_nicInfo(nics)
time.sleep(2)
net_status1=get_nicInfo(nics)
for nic in nics:
print "netcard_name :%s" % nic
print "transmit_speed :%s" % str((int(net_status1[nic][0])-int(net_status0[nic][0]))/2048)
print "receive_speed :%s" % str((int(net_status1[nic][1])-int(net_status0[nic][1]))/2048)

 

初次写博，请各位大神手下留情，请轻喷！

参考：

Libvirt 官网API定义

virDomainBlockInfo

struct virDomainBlockInfo {

unsigned long long	capacity	logical size in bytes of the block device backing image
unsigned long long	allocation	highest allocated extent in bytes of the block device backing image
unsigned long long	physical	physical size in bytes of the container of the backing image

}

 

virDomainBlockStatsStruct

struct virDomainBlockStatsStruct {

long long	rd_req	number of read requests
long long	rd_bytes	number of read bytes
long long	wr_req	number of write requests
long long	wr_bytes	number of written bytes
long long	errs	In Xen this returns the mysterious 'oo_req'.

}

 

http://libvirt.org/html/libvirt-libvirt.html