用snmp+mrtg可以很好的实现对局域网内服务器状态的监控。
现在就以用snmp+mrtg监控一台局域网内的redhat机器（IP：192.168.13.103）的网卡、内存、CPU、 DISKIO为例子，谈一下如何实现。
基本的法办就是用一台redhat监控机器（IP：192.168.13.105），通过snmpwalk命令去抓 目标服务器的状态数据，然后用mrtg画出图来。
1、首先我们要把目标snmpd.conf文件的配好。这是用snmpwalk命令 一抓取数据的关健。下面是目标机器（IP： 192.168.13.103）上的/etc/snmp/snmpd.conf文件部份内容，红色的部份是我对snmpd.conf所做的改动。
[root@wy1 root]# cat /etc/snmp/snmpd.conf
####
# First, map the community name "public" into a "security name"
# sec.name source community
com2sec notConfigUser default public #定义community名称为 public，映射到安全名 notConfigUser。
####
# Second, map the security name into a group name:
# groupName securityModel securityName
group notConfigGroup v1 notConfigUser #定义安全用户名notConfigUser映射到notConfigGroup组。
group notConfigGroup v2c notConfigUser
####
# Third, create a view for us to let the group have rights to: #定义一个view,来决定notConfigUser可以操作的范围。
# Make at least snmpwalk -v 1 localhost -c public system fast again. #定义可查看的snmp的范围。
# name incl/excl subtree mask(optional)
view systemview included .1.3.6.1.2.1.1
view systemview included .1.3.6.1.2.1.25.1.1
view all included .1
####
# Finally, grant the group read-only access to the systemview view. #给notConfigGroup组所定义view名 all 以只读权限。
# group context sec.model sec.level prefix read write notif
access notConfigGroup "" any noauth exact all none none
#access notConfigGroup "" any noauth exact mib2 none none
# -----------------------------------------------------------------------------
# Here is a commented out example configuration that allows less
# restrictive access.
# YOU SHOULD CHANGE THE "COMMUNITY" TOKEN BELOW TO A NEW KEYWORD ONLY
# KNOWN AT YOUR SITE. YOU *MUST* CHANGE THE NETWORK TOKEN BELOW TO
# SOMETHING REFLECTING YOUR LOCAL NETWORK ADDRESS SPACE.
## sec.name source community
#com2sec local localhost COMMUNITY
#com2sec mynetwork NETWORK/24 COMMUNITY
## group.name sec.model sec.name
#group MyRWGroup any local
#group MyROGroup any mynetwork
#
#group MyRWGroup any otherv3user
#...
## incl/excl subtree mask
#view all included .1 80
## -or just the mib2 tree-
#view mib2 included .iso.org.dod.internet.mgmt.mib-2 fc
#view mib2 included .iso.org.dod.internet.mgmt.mib-2 fc
## context sec.model sec.level prefix read write notif
#access MyROGroup "" any noauth 0 all none none
#access MyRWGroup "" any noauth 0 all all all
其实配制一个snmpd.conf文件不算太难，
（1）首选是定义一个共同体名(community)，这里是public，及可以访问这个public的用户名（sec name），这里是notConfigUser。Public相当于用户notConfigUser的密码：）
# sec.name source community
com2sec notConfigUser default public
（2）定义一个组名（groupName）这里是notConfigGroup，及组的安全级别，把notConfigGroup这个用户加到这个组中。
groupName securityModel securityName
group notConfigGroup v1 notConfigUser
group notConfigGroup v2c notConfigUser
（3）定义一个可操作的范围(view)名， 这里是all，范围是 .1
# name incl/excl subtree mask(optional)
view all included .1
（4）定义notConfigUser这个组在all这个view范围内可做的操作，这时定义了notConfigUser组的成员可对.1这个范围做只读操作。
# group context sec.model sec.level prefix read write notif
access notConfigGroup "" any noauth exact all none none
ok,这样我们的snmpd.conf文件就基本配成了，用service snmpd restart重启snmpd服务。现在我们做一个测试，在监控机上打下面的命令：
[root@wy2 root]# snmpwalk -v 1 192.168.13.103 -c public system
SNMPv2-MIB::sysDescr.0 = STRING: Linux wy1 2.4.20-8smp #1 SMP Thu Mar 13 17:45:54 EST 2003 i686
SNMPv2-MIB::sysObjectID.0 = OID: NET-SNMP-MIB::netSnmpAgentOIDs.10
SNMPv2-MIB::sysUpTime.0 = Timeticks: (7565377) 21:00:53.77
SNMPv2-MIB::sysContact.0 = STRING: Root <root@wuying.com> (configure /etc/snmp/snmp.local.conf)
SNMPv2-MIB::sysName.0 = STRING: wy1
SNMPv2-MIB::sysLocation.0 = STRING: wy1.wuying.com (edit /etc/snmp/snmpd.conf)
SNMPv2-MIB::sysORLastChange.0 = Timeticks: (10) 0:00:00.10
``````````````````````
“Linux wy1 2.4.20-8smp”操作系统的信息已经出来了：）
现在我们在目标机上来写一些脚本来显标MEM、CPU、DiskIO
MEM数据的抓取脚本：
[root@wy1 root]# cat mfree.sh
#!/bin/sh
/usr/bin/free -m | grep Mem |awk '{print $4}'
/usr/bin/free -m | grep Mem |awk '{print $2}'
[root@wy1 root]# sh mfree.sh (上面一个数据是内存使用量，下面的是内存总量,M)
442
1006
CPU数据的抓取脚本
[root@wy1 root]# cat cpustat.sh
#!/bin/sh
idle=`sar -u 1 3 | grep Average | awk '{print $6}'`
used=`echo "101 - $idle" | bc -l -s`
echo $used
echo $idle
DiskIO数据的抓取脚本
[root@wy1 root]# cat iostat.sh （显示硬盘IO，k/s）
#!/bin/sh
used1=`sar -d 1 3 | tail -1 | awk '{print $4}'`
used2=`echo "$used1 / 2" | bc -l`
echo $used2
echo $used2
好现在我们已经能得到这数据了，怎么才能让监控主机通过snmpd得到这些数据呢？可以在目标主机的/etc/snmp/snmpd.conf文件下面加个这些行：
exec .1.3.6.1.4.1.2021.53 mfree /bin/sh /root/mfree.sh
exec .1.3.6.1.4.1.2021.54 cpustat /bin/sh /root/cpustat.sh
exec .1.3.6.1.4.1.2021.55 iostat /bin/sh /root/iostat.sh
service snmpd restart 重启目标主机上的snmpd服务。
这样在监控主机上运行:
[root@wy2 root]# snmpwalk -v 1 192.168.13.103 -c public .1.3.6.1.4.1.2021.53
UCD-SNMP-MIB::ucdavis.53.1.1 = INTEGER: 1
UCD-SNMP-MIB::ucdavis.53.2.1 = STRING: "mfree"
UCD-SNMP-MIB::ucdavis.53.3.1 = STRING: "/bin/sh /root/mfree.sh"
UCD-SNMP-MIB::ucdavis.53.100.1 = INTEGER: 0
UCD-SNMP-MIB::ucdavis.53.101.1 = STRING: "442"
UCD-SNMP-MIB::ucdavis.53.101.2 = STRING: "1006"
UCD-SNMP-MIB::ucdavis.53.102.1 = INTEGER: 0
其中UCD-SNMP-MIB::ucdavis.53.101.1 = STRING: "442" 中的442就是mfree.sh输出的第一个数据，1006是mfree.sh输出的第二个数据。OK，再做一下加工：
[root@wy2 root]# snmpwalk -v 1 192.168.13.103 -c public .1.3.6.1.4.1.2021.53 | grep 53.101 | awk -F\" '{print $2}'
443
1006
好，我们已经通过snmpd从监控主机上得到了目标主机上内存使用的这两个数据了：）,其它的两个脚本也一样：
CPU使用、空闲。
[root@wy2 root]# snmpwalk -v 1 192.168.13.103 -c public .1.3.6.1.4.1.2021.54 | grep 54.101 | awk -F\" '{print $2}'
1.17
99.83
DISK IO 状态：
[root@wy2 root]# snmpwalk -v 1 192.168.13.103 -c public .1.3.6.1.4.1.2021.55 | grep 55.101 | awk -F\" '{print $2}'
43.00000000000000000000
43.00000000000000000000
最 后是编辑监控主机上的mrtg.cfg文件，在Target[xxxx]中加入上面的命令，下面是我的mrtg.cfg文件，前面的两个 Target是我用/usr/bin/cfgmaker --global 'WorkDir: /home/httpd/mrtg/net' --
global 'Options[_]:growright,bits' --ifref=ip public@192.168.13.103 命令生 成的，
后面的是我跟据platinum 的"mrtg能做些什么"的贴子内的mrtg.cfg文件改的。（在精华里，大家可以看一下）。
[root@wy1 root]# cat /home/httpd/mrtg/103/mrtg.cfg
# Created by
# /usr/bin/cfgmaker --global 'WorkDir: /home/httpd/mrtg/net' --global 'Options[_]:growright,bits' --ifref=ip public@192.168.13.103
### Global Config Options
# for UNIX
# WorkDir: /home/http/mrtg
# or for NT
# WorkDir: c:\mrtgdata
### Global Defaults
# to get bits instead of bytes and graphs growing to the right
# Options[_]: growright, bits
WorkDir: /home/httpd/mrtg/103
Options[_]:growright,bits
Language: chinese
######################################################################
# System: wy1
# Description: Linux wy1 2.4.20-8smp #1 SMP Thu Mar 13 17:45:54 EST 2003 i686
# Contact: Root <root@wuying.com> (configure /etc/snmp/snmp.local.conf)
# Location: wy1.wuying.com (edit /etc/snmp/snmpd.conf)
######################################################################
### Interface 2 >> Descr: 'eth0' | Name: '' | Ip: '192.168.13.103' | Eth: '00-06-5b-19-9d-ea' ###
Target[192.168.13.103_192.168.13.103]: /192.168.13.103:public@192.168.13.103:
SetEnv[192.168.13.103_192.168.13.103]: MRTG_INT_IP="192.168.13.103" MRTG_INT_DESCR="eth0"
MaxBytes[192.168.13.103_192.168.13.103]: 1250000
Xsize[192.168.13.103_192.168.13.103]: 300
Ysize[192.168.13.103_192.168.13.103]: 100
#kmg[192.168.13.103_192.168.13.103]: K/s,M/s
#kilo[192.168.13.103_192.168.13.103]: 1024
Title[192.168.13.103_192.168.13.103]: Traffic for eth0 192.168.13.103 -- wy1
PageTop[192.168.13.103_192.168.13.103]: Traffic for eth0 192.168.13.103 -- wy1
#Options[192.168.13.103_192.168.13.103]: growright,gauge,nopercent
### Interface 3 >> Descr: 'eth1' | Name: '' | Ip: '172.16.0.188' | Eth: '00-06-5b-19-9d-e9' ###
Target[192.168.13.103_172.16.0.188]: /172.16.0.188:public@192.168.13.103:
SetEnv[192.168.13.103_172.16.0.188]: MRTG_INT_IP="172.16.0.188" MRTG_INT_DESCR="eth1"
Xsize[192.168.13.103_172.16.0.188]: 300
Ysize[192.168.13.103_172.16.0.188]: 100
MaxBytes[192.168.13.103_172.16.0.188]: 1250000
#ShortLegend[192.168.13.103_172.16.0.188]:
#kmg[192.168.13.103_172.16.0.188]: b/s,Kb/s
#kilo[192.168.13.103_172.16.0.188]: 1024
Title[192.168.13.103_172.16.0.188]: Traffic for eth1 172.16.0.188 -- wy1
PageTop[192.168.13.103_172.16.0.188]: Traffic for eth1 172.16.0.188 -- wy1
#Options[192.168.13.103_172.16.0.188]: growright,gauge,nopercent
###MEM status
Target[wy1_mem]:`snmpwalk -v 1 192.168.13.103 -c public .1.3.6.1.4.1.2021.53 | grep 53.101 | awk -F\" '{print $2}'`
#Targey[wy1_mem]: memTotalReal.0&memAvailReal.0:holdata@holdata.3322.org
Xsize[wy1_mem]: 300
Ysize[wy1_mem]: 100
Ytics[wy1_mem]: 7
MaxBytes[wy1_mem]: 1006
Title[wy1_mem]:Memory State of WY1 IP 192.168.13.103 Server
PageTop[wy1_mem]:Memory State of WY1 IP 192.168.13.103 Server
ShortLegend[wy1_mem]: MB
kmg[wy1_mem]: MB
kilo[wy1_mem]:1024
YLegend[wy1_mem]: Memory Usage
Legend1[wy1_mem]: 可用内存
Legend2[wy1_mem]: 总内存量
Legend3[wy1_mem]: 可用内存
Legend4[wy1_mem]: 总内存量
LegendI[wy1_mem]: 可用内存
LegendO[wy1_mem]: 总内存量
Options[wy1_mem]: growright,gauge,nopercent
###cpu status
Target[wy1_CPU]:`snmpwalk -v 1 192.168.13.103 -c public .1.3.6.1.4.1.2021.54 | grep 54.101 | awk -F\" '{print $2}'`
#Targey[wy1_CPU]: memTotalReal.0&memAvailReal.0:holdata@holdata.3322.org
Xsize[wy1_CPU]: 300
Ysize[wy1_CPU]: 100
Ytics[wy1_CPU]: 7
MaxBytes[wy1_CPU]: 100
Title[wy1_CPU]:CPU State of WY1 IP 192.168.13.103 Server
PageTop[wy1_CPU]:CPU State of WY1 IP 192.168.13.103 Server
ShortLegend[wy1_CPU]:
kmg[wy1_CPU]: %
#kilo[wy1_CPU]:1024
YLegend[wy1_CPU]: CPU Usage
Legend1[wy1_CPU]: 已用CPU:
Legend2[wy1_CPU]: 可用CPU:
LegendI[wy1_CPU]: 已用CPU:
LegendO[wy1_CPU]: 可用CPU:
Options[wy1_CPU]: growright,gauge,nopercent
###iostat
###cpu status
Target[wy1_IO]:`snmpwalk -v 1 192.168.13.103 -c public .1.3.6.1.4.1.2021.55 | grep 55.101 | awk -F\" '{print $2}'`
#Targey[wy1_IO]: memTotalReal.0&memAvailReal.0:holdata@holdata.3322.org
Xsize[wy1_IO]: 300
Ysize[wy1_IO]: 100
Ytics[wy1_IO]: 7
MaxBytes[wy1_IO]: 10000
Title[wy1_IO]: DISK IO State of WY1 IP 192.168.13.103 Server
PageTop[wy1_IO]:DISK IO State of WY1 IP 192.168.13.103 Server
ShortLegend[wy1_IO]:
kmg[wy1_IO]: K/s,M/s
kilo[wy1_IO]:1024
YLegend[wy1_IO]: DISK IO SPEED
Legend1[wy1_IO]: IO速度:
Legend2[wy1_IO]: IO速度:
LegendI[wy1_IO]: IO速度:
LegendO[wy1_IO]: IO速度:
Options[wy1_IO]: growright,gauge,nopercent
用indexmaker -o /home/httpd/mrtg/103/index.html /home/httpd/mrtg/103/mrtg.cfg 生成网页，在crontab 中加入*/5 * * * * mrtg /home/httpd/mrtg/103/mrtg.cfg
OK， 这样我们就能通过mrtg生成的图来监控我们linux的机器的状态了。在IE中打入http: //192.168.13.105/mrtg/103,mrtg的监控网页就出来啦
（/home/httpd/是我appache的主目录）。当然我们也 能用snmpwalk命令来得到安装有snmp服务的win2000机器的状态的数据：
如：
[root@wy1 103]# snmpwalk -v 1 192.168.1.5 -c public HOST-RESOURCES-MIB::hrStorage
HOST-RESOURCES-MIB::hrMemorySize.0 = INTEGER: 3800424 KBytes
HOST-RESOURCES-MIB::hrStorageIndex.1 = INTEGER: 1
HOST-RESOURCES-MIB::hrStorageIndex.2 = INTEGER: 2
HOST-RESOURCES-MIB::hrStorageIndex.3 = INTEGER: 3
HOST-RESOURCES-MIB::hrStorageIndex.4 = INTEGER: 4
HOST-RESOURCES-MIB::hrStorageIndex.5 = INTEGER: 5
HOST-RESOURCES-MIB::hrStorageIndex.6 = INTEGER: 6
HOST-RESOURCES-MIB::hrStorageType.1 = OID: HOST-RESOURCES-TYPES::hrStorageRemovableDisk
HOST-RESOURCES-MIB::hrStorageType.2 = OID: HOST-RESOURCES-TYPES::hrStorageFixedDisk
HOST-RESOURCES-MIB::hrStorageType.3 = OID: HOST-RESOURCES-TYPES::hrStorageFixedDisk
HOST-RESOURCES-MIB::hrStorageType.4 = OID: HOST-RESOURCES-TYPES::hrStorageFixedDisk
HOST-RESOURCES-MIB::hrStorageType.5 = OID: HOST-RESOURCES-TYPES::hrStorageCompactDisc
HOST-RESOURCES-MIB::hrStorageType.6 = OID: HOST-RESOURCES-TYPES::hrStorageVirtualMemory
HOST-RESOURCES-MIB::hrStorageDescr.1 = STRING: A:\
HOST-RESOURCES-MIB::hrStorageDescr.2 = STRING: C:\ Label: Serial Number 581e89fe
HOST-RESOURCES-MIB::hrStorageDescr.3 = STRING: D:\ Label:New Volume Serial Number 1cde6e55
HOST-RESOURCES-MIB::hrStorageDescr.4 = STRING: E:\ Label:DATA_BAK Serial Number 30d29147
HOST-RESOURCES-MIB::hrStorageDescr.5 = STRING: F:\
HOST-RESOURCES-MIB::hrStorageDescr.6 = STRING: Virtual Memory
HOST-RESOURCES-MIB::hrStorageAllocationUnits.1 = INTEGER: 0 Bytes
HOST-RESOURCES-MIB::hrStorageAllocationUnits.2 = INTEGER: 4096 Bytes
HOST-RESOURCES-MIB::hrStorageAllocationUnits.3 = INTEGER: 4096 Bytes
HOST-RESOURCES-MIB::hrStorageAllocationUnits.4 = INTEGER: 4096 Bytes
HOST-RESOURCES-MIB::hrStorageAllocationUnits.5 = INTEGER: 0 Bytes
HOST-RESOURCES-MIB::hrStorageAllocationUnits.6 = INTEGER: 65536 Bytes
HOST-RESOURCES-MIB::hrStorageSize.1 = INTEGER: 0
HOST-RESOURCES-MIB::hrStorageSize.2 = INTEGER: 2050287
HOST-RESOURCES-MIB::hrStorageSize.3 = INTEGER: 15703529
HOST-RESOURCES-MIB::hrStorageSize.4 = INTEGER: 53263499
HOST-RESOURCES-MIB::hrStorageSize.5 = INTEGER: 0
HOST-RESOURCES-MIB::hrStorageSize.6 = INTEGER: 89444
HOST-RESOURCES-MIB::hrStorageUsed.1 = INTEGER: 0
HOST-RESOURCES-MIB::hrStorageUsed.2 = INTEGER: 1233681
HOST-RESOURCES-MIB::hrStorageUsed.3 = INTEGER: 591593
HOST-RESOURCES-MIB::hrStorageUsed.4 = INTEGER: 23583930
HOST-RESOURCES-MIB::hrStorageUsed.5 = INTEGER: 0
HOST-RESOURCES-MIB::hrStorageUsed.6 = INTEGER: 50611
HOST-RESOURCES-MIB::hrStorageAllocationFailures.1 = Counter32: 0
HOST-RESOURCES-MIB::hrStorageAllocationFailures.2 = Counter32: 0
HOST-RESOURCES-MIB::hrStorageAllocationFailures.3 = Counter32: 0
HOST-RESOURCES-MIB::hrStorageAllocationFailures.4 = Counter32: 0
HOST-RESOURCES-MIB::hrStorageAllocationFailures.5 = Counter32: 0
HOST-RESOURCES-MIB::hrStorageAllocationFailures.6 = Counter32: 0
上面显示的是192.168.1.5这台win2000SERVER的磁盘信息，可以看到盘符、每个分区的空间总量、使用量等。其它的相应建值还有：
Diskused: HOST-RESOURCES-MIB::hrStorageUsed
CPU: HOST-RESOURCES-MIB::hrProcessorLoad
RUN Proc: HOST-RESOURCES-MIB::hrSWRunName
SYS Uptime: HOST-RESOURCES-MIB::hrSystemUptime SNMPv2-MIB::sysUpTime
SYS Date: HOST-RESOURCES-MIB::hrSystemDate
SYS Device: HOST-RESOURCES-MIB::hrDeviceDescr
SYS Descr: SNMPv2-MIB::sysDescr
SYS Name: SNMPv2-MIB::sysName
netcard speed: IF-MIB::ifSpeed
netcard physcal address: IF-MIB::ifPhysAddress
这样我们就可以用一台linux主机通过snmp+mrtg来监控多台局域网内的linux/win2000SERVER了：）。
现在我最关心的是如何让snmp包穿过防火墙，（我用snmpwalk试了一下，抓不到公司在IDC防火墙后的SERVER的snmp数据）。
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