CentOS Linux release 7.3.1611
NET-SNMP version: 5.7.2

YUM 安装

yum install -y net-snmp net-snmp-utils

使用snmptranslate命令，检查snmp工具是否可以使用
[root@test~]# snmptranslate -To | head
.1.3
.1.3.6
.1.3.6.1
.1.3.6.1.1
.1.3.6.1.2
.1.3.6.1.2.1
.1.3.6.1.2.1.1
.1.3.6.1.2.1.1.1
.1.3.6.1.2.1.1.2
.1.3.6.1.2.1.1.3

使用snmpwalk命令，查看本机localhost的主机名： 主机名

[root@test~]# snmpwalk -v 2c -c public localhost sysName.0
SNMPv2-MIB::sysName.0 = STRING: test

---

二、配置snmp服务

以上安装完成后，使用的是snmp的默认配置，通过这些默认配置，我们只能获取主机的部分信息。但一些其他的重要信息，无法获取。如主机的CPU使用情况，内存使用情况等。

[root@test~]# snmpwalk -v 2c -c public localhost 1.3.6.1.4.1.2021.11.11.0  
snmpwalk -v 2c -c public localhost 1.3.6.1.4.1.2021.11.ssCpuIdle

UCD-SNMP-MIB::ssCpuIdle.0 = No more variables left in this MIB View (It is past the end of the MIB tree)

如上，无法获取CPU的空闲率（注：1.3.6.1.4.1.2021.11.11.0是主机CPU空闲率的oid）。

这时候，若要获取主机的一些重要信息，则要修改snmp的默认配置。

配置方法：修改/etc/snmp/snmpd.conf文件

1、修改查看设备节点的权限
在该文件中，找到如下位置：

# Third, create a view for us to let the group have rights to:

# Make at least  snmpwalk -v 1 localhost -c public system fast again.
#       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：定义了可以查看哪些节点设备的信息。

snmp默认配置只能查看.1.3.6.1.2.1.1和.1.3.6.1.2.1.25.1.1节点下的设备信息，而主机CPU和内存等设备都不在这些节点下，所以无法获取这些数据。

因此，可以修改这个配置，如下：

# Third, create a view for us to let the group have rights to:

# Make at least  snmpwalk -v 1 localhost -c public system fast again.
#       name           incl/excl     subtree         mask(optional)
view    systemview    included   .1
view    systemview    included   .1.3.6.1.2.1.1
view    systemview    included   .1.3.6.1.2.1.25.1.1

在此处添加了一行：

view systemview included .1

表示可以查看.1节点下的所有设备信息。

2、修改Process checks的配置
找到如下位置：
###############################################################################
# Process checks.
#
# The following are examples of how to use the agent to check for
# processes running on the host. The syntax looks something like:
#
# proc NAME [MAX=0] [MIN=0]
#
# NAME: the name of the process to check for. It must match
# exactly (ie, http will not find httpd processes).
# MAX: the maximum number allowed to be running. Defaults to 0.
# MIN: the minimum number to be running. Defaults to 0.

#
#  Examples (commented out by default):
#

#  Make sure mountd is running
proc mountd

#  Make sure there are no more than 4 ntalkds running, but 0 is ok too.
proc ntalkd 4

#  Make sure at least one sendmail, but less than or equal to 10 are running.
proc sendmail 10 1

将

proc mountd

proc ntalkd 4

proc sendmail 10 1

三行前的“#”号去掉，取消注释

3、修改Executables/scripts配置
找到如下位置：

###############################################################################
# Executables/scripts
#

#
#  You can also have programs run by the agent that return a single
#  line of output and an exit code.  Here are two examples.
#
#  exec NAME PROGRAM [ARGS ...]
#
#  NAME:     A generic name. The name must be unique for each exec statement.
#  PROGRAM:  The program to run.  Include the path!
#  ARGS:     optional arguments to be passed to the program

# a simple hello world

exec echotest /bin/echo hello world

# Run a shell script containing:
#
# #!/bin/sh
# echo hello world
# echo hi there
# exit 35
#
# Note:  this has been specifically commented out to prevent
# accidental security holes due to someone else on your system writing
# a /tmp/shtest before you do.  Uncomment to use it.
#
#exec shelltest /bin/sh /tmp/shtest

将

exec echotest /bin/echo hello world

的“#”号去掉，取消注释。

4、修改disk checks配置
找到如下位置：

###############################################################################
# disk checks
#

# The agent can check the amount of available disk space, and make
# sure it is above a set limit.  

# disk PATH [MIN=100000]
#
# PATH:  mount path to the disk in question.
# MIN:   Disks with space below this value will have the Mib's errorFlag set.
#        Default value = 100000.

# Check the / partition and make sure it contains at least 10 megs.

disk / 10000

# % snmpwalk -v 1 localhost -c public .1.3.6.1.4.1.2021.9
# enterprises.ucdavis.diskTable.dskEntry.diskIndex.1 = 0
# enterprises.ucdavis.diskTable.dskEntry.diskPath.1 = "/" Hex: 2F 
# enterprises.ucdavis.diskTable.dskEntry.diskDevice.1 = "/dev/dsk/c201d6s0"
# enterprises.ucdavis.diskTable.dskEntry.diskMinimum.1 = 10000
# enterprises.ucdavis.diskTable.dskEntry.diskTotal.1 = 837130
# enterprises.ucdavis.diskTable.dskEntry.diskAvail.1 = 316325
# enterprises.ucdavis.diskTable.dskEntry.diskUsed.1 = 437092
# enterprises.ucdavis.diskTable.dskEntry.diskPercent.1 = 58
# enterprises.ucdavis.diskTable.dskEntry.diskErrorFlag.1 = 0
# enterprises.ucdavis.diskTable.dskEntry.diskErrorMsg.1 = ""

将

disk / 10000

一行前的“#”号去掉，取消注释。

5、修改load average checks配置
找到如下位置：

###############################################################################
# load average checks
#

# load [1MAX=12.0] [5MAX=12.0] [15MAX=12.0]
#
# 1MAX:   If the 1 minute load average is above this limit at query
#         time, the errorFlag will be set.
# 5MAX:   Similar, but for 5 min average.
# 15MAX:  Similar, but for 15 min average.

# Check for loads:
load 12 14 14

将 #load 12 14 14

一行前的“#”号去掉，取消注释。

6、保存修改，重启snmp服务

7、验证修改配置后的snmp服务

如上，通过本机localhost获取到CPU的空闲率为99%。

snmpwalk -v 2c -c public localhost 1.3.6.1.4.1.2021.11.11.0
UCD-SNMP-MIB::ssCpuIdle.0 = INTEGER: 99