一、获取交换机snmp信息

snmp服务IP（交换机IP）：172.20.2.83

snmp community：dfetest

二、部署 snmp_exporter

2.1 下载snmp_exporter

下载snmp_exporter安装包，下载地址：https://github.com/prometheus/snmp_exporter/releases

下载完成后，上传至机器的 /usr/local 目录下

解压安装包

#   tar -zvxf snmp_exporter-0.15.0.linux-arm64.tar.gz 
#   mv snmp_exporter-0.15.0.linux-arm64/ snmp_exporter

2.2 配置snmp_exporter

snmp_exporter的配置文件需要自己通过SNMP Exporter Config Generator 项目编译生成，

参考方法： https://github.com/prometheus/snmp_exporter/tree/master/generator#file-format

由于Prometheus使用go语言开发的，所以自己编译生成snmp_exporter的配置文件需要go环境，Linux中安装go环境可参考：https://www.cnblogs.com/guoxiangyue/p/11772717.html 中安装go环境章节

go环境安装以后，构建snmp exporter config Generator，执行以下操作：

#  yum -y install git
#  yum -y install gcc gcc-g++ make net-snmp net-snmp-utils net-snmp-libs net-snmp-devel
#  go get github.com/prometheus/snmp_exporter/generator
#  cd ${GOPATH-$HOME/go}/src/github.com/prometheus/snmp_exporter/generator
#  go build
#  make mibs

编译完成后，修改当前目录下的generator.yml 文件，generator.yml文件的配置可以参考 https://github.com/prometheus/snmp_exporter/tree/master/generator#file-format ，generator.yml文件中只需要注入snmp的community即可,下面仅修改了modules.if_mib.auth字段，其余与 File Format 中一致。

#  vim generator.yml

generator.yml 中module.if_mib.auth字段：

modules:
  # Default IF-MIB interfaces table with ifIndex.
  if_mib:
    walk: [sysUpTime, interfaces, ifXTable]
    version: 1
    auth:
      community: dfetest
    lookups:
      - source_indexes: [ifIndex]
        lookup: ifAlias
      - source_indexes: [ifIndex]
        lookup: ifDescr
      - source_indexes: [ifIndex]
        # Use OID to avoid conflict with Netscaler NS-ROOT-MIB.
        lookup: 1.3.6.1.2.1.31.1.1.1.1 # ifName
    overrides:
      ifAlias:
        ignore: true # Lookup metric
      ifDescr:
        ignore: true # Lookup metric
      ifName:
        ignore: true # Lookup metric
      ifType:
        type: EnumAsInfo

修改完成后，保存退出，执行以下操作，生成新的 snmp.yml 文件

#   export MIBDIRS=mibs
#   ./generator generate

将新生成的snmp.yml 替换掉原snmp_exporter中的snmp.yml

#   cp snmp.yml /usr/local/snmp_exporter

2.3 验证并设置snmp_exporter 服务开机启动

#   cd /usr/local/snmp_exporter
#   ./snmp_exporter

开启服务端口在9116上，浏览器访问 http://192.168.56.200:9116 , 在 Target 输入框中填入交换机IP地址，点击 submit 按钮，出现数据，在snmp_exporter 配置成功。

2.4 设置snmp_exporter 以服务方式，开机启动

Ctrl+C 结束掉 snmp_exporter 进程，创建 snmp_exporter 服务，让 snmp_exporter 以服务的方式，开机自启。

添加系统服务

#   vim /etc/systemd/system/snmp_exporter.service

将以下内容写入文件中

[Unit]
Description=node_exporter
After=network.target 

[Service]
ExecStart=/usr/local/snmp_exporter/snmp_exporter
Restart=on-failure

[Install]
WantedBy=multi-user.target

启动服务，设置开机自启

#  systemctl daemon-reload
#  systemctl enable snmp_exporter 
#  systemctl start snmp_exporter

三、修改Prometheus 配置

进入Prometheus的安装文件夹，打开Prometheus配置文件

#  cd /usr/local/prometheus
#  vim prometheus.yml

在scrape_configs标签下，添加以下内容，配置监控。params.module中可以配置需要抓取的模块，不配置表示全部抓取。

- job_name: 'snmp'
    scrape_interval: 10s
    static_configs:
     - targets:
       - 172.20.2.83  # 交换机IP地址
    metrics_path: /snmp
    # params:
     # module: [if_mib]
    relabel_configs:
      - source_labels: [__address__]
        target_label: __param_target
      - source_labels: [__param_target]
        target_label: instance
      - target_label: __address__
        replacement: 192.168.56.200:9116 # snmp_exporter 服务IP地址

以下是Prometheus.yml 文件全部内容

# my global config
global:
  scrape_interval:     15s # Set the scrape interval to every 15 seconds. Default is every 1 minute.
  evaluation_interval: 15s # Evaluate rules every 15 seconds. The default is every 1 minute.
  # scrape_timeout is set to the global default (10s).

# Alertmanager configuration
alerting:
  alertmanagers:
  - static_configs:
    - targets:
      # - alertmanager:9093

# Load rules once and periodically evaluate them according to the global 'evaluation_interval'.
rule_files:
  # - "first_rules.yml"
  # - "second_rules.yml"

# A scrape configuration containing exactly one endpoint to scrape:
# Here it's Prometheus itself.
scrape_configs:
  # The job name is added as a label `job=<job_name>` to any timeseries scraped from this config.
  - job_name: 'prometheus'

    # metrics_path defaults to '/metrics'
    # scheme defaults to 'http'.

    static_configs:
    - targets: ['localhost:9090']

  - job_name: 'Linux'
    static_configs:
    - targets: ['192.168.56.201:9100']
      labels:
        instance: Linux

  - job_name: 'Windows'
    static_configs:
    - targets: ['192.168.56.1:9182']
      labels:
        instance: Windows

  - job_name: 'snmp'
    scrape_interval: 10s
    static_configs:
     - targets:
       - 172.20.2.83  # 交换机IP地址
    metrics_path: /snmp
    # params:
     # module: [if_mib]
    relabel_configs:
      - source_labels: [__address__]
        target_label: __param_target
      - source_labels: [__param_target]
        target_label: instance
      - target_label: __address__
        replacement: 192.168.56.200:9116 # snmp_exporter 服务IP地址