Nagios Core 4 於 Debian Linux Stretch 架設

Nagios 3 的設定、架設等等，可以參考此篇：Nagios 安裝設定 於 Debian、Ubuntu Linux

上述是使用 Debian、Ubuntu Linux 官方包的 APT 套件架設，此篇介紹的是直接下載 Source code 來編譯架設。

Nagios Core 4 於 Debian Linux Stretch 架設

首先先說明為何要這麼費工手動編譯 Source code...

因為 Debian Linux Stretch 的 Nagios 3 不見了，而且要裝回 jessie 版的 Nagios 3 也因為套件衝突無法安裝，所以只好手動編譯來架設 Nagios 4。

先來看看 Nagios 3 和 Nagios 4 的差異

• What's New in Core 4 - Nagios
• difference between Nagios® Core™ 3.2.3 and Nagios® Core™ 4.0

Nagios 架設需要下述幾個套件：

• Nagios Core
• Nagios Plugins # 可以想成是 client，都是 check script
• Nagios NRPE # 監控遠端機器會需要這個套件

Nagios 4 Core 下載

• Downloading Nagios Core - Nagios

Nagios 4 Core 安裝架設

下述步驟參考自此篇：Nagios 4 安裝架設參考文件 PDF：Installing Nagios Core From Source

1. wget http://prdownloads.sourceforge.net/sourceforge/nagios/nagios-4.2.0.tar.gz # 可自行於官網下載最新版
2. sudo apt-get install build-essential libgd-dev php-gd
3. sudo useradd nagios
4. sudo groupadd nagcmd
5. sudo usermod -a -G nagcmd nagios
6. sudo usermod -a -G nagios,nagcmd www-data
7. tar zxvf nagios-4.2.0.tar.gz
8. cd nagios-4.2.0
9. ./configure --with-command-group=nagios --with-mail=/usr/sbin/sendmail --with-httpd-conf=/etc/apache2/
   • Nagios executable: nagios
   • Nagios user/group: nagios,nagios
   • Command user/group: nagios,nagios
   • Install ${prefix}: /usr/local/nagios
   • Install ${includedir}: /usr/local/nagios/include/nagios
   • Lock file: ${prefix}/var/nagios.lock
   • Check result directory: ${prefix}/var/spool/checkresults
   • Init directory: /etc/init.d
   • Apache conf.d directory: /etc/apache2/
   • Mail program: /usr/sbin/sendmail
   • IOBroker Method: epoll
   • Web Interface Options:
     • HTML URL: http://localhost/nagios/
     • CGI URL: http://localhost/nagios/cgi-bin/
     • Traceroute (used by WAP): /usr/bin/traceroute
   • config
     • /usr/local/nagios/etc
     • /etc/apache2/conf.d/nagios.conf

Nagios 4 Plugins 安裝架設

1. wget http://nagios-plugins.org/download/nagios-plugins-2 .1.2.tar.gz # 可自行於官網下載最新版
2. tar zxvf nagios-plugins-2.1.2.tar.gz
3. cd nagios-plugins-2.1.2
4. ./configure
5. make
6. # make check # 這個步驟可以跳過，此步驟要輸入很多東西，大概會花掉1hr
7. sudo make install
8. make installcheck

Nagios 4 NRPE 安裝架設

下述架設參考自下述：

• Nagios Enterprises NRPE 安裝文件 PDF：nrpe/NRPE.pdf at master · NagiosEnterprises/nrpe
• 官網：GitHub - NagiosEnterprises/nrpe: NRPE Agent

NRPE 安裝步驟

1. apt install libssl-dev # ./configure 遇到 configure: error: Cannot find ssl headers
2. git clone https://github.com/NagiosEnterprises/nrpe/
3. cd nrpe
4. ./configure
5. make all
6. make install-groups-users
7. make install
8. make install-config
9. make install-inetd
10. make install-init
11. systemctl enable nrpe
12. systemctl start nrpe
13. netstat -at | egrep "nrpe|5666"
14. /usr/local/nagios/libexec/check_nrpe -H localhost
    NRPE v3.0
15. cat /etc/systemd/system/multi-user.target.wants/nrpe.service # 確認 systemd 有 nrpe.service
16. sudo systemctl restart nrpe.service # 重新啟動看看
17. sudo ln -s /usr/local/nagios/etc /etc/nagios # 將設定檔丟到 /etc/nagios 方便 Debian 以前的設定習慣

測試

• /usr/local/nagios/libexec/check_nrpe -H 127.0.0.1
• /usr/local/nagios/libexec/check_nrpe -H 127.0.0.1 -c check_load

Nagios 幾個參數設定

增加 check_nrpe_1arg 的參數

• vim /etc/nagios/object/commands.cfg # 最下面增加下述
  define command {
  command_name check_nrpe_1arg
  command_line $USER1$/check_nrpe $ARG1$
  }

設定通知人、Email (ops)

• sudo vim /etc/nagios/objects/contacts.cfg # 找到 email 修改即可

Nagios 3 與 Nagios 4 Client V2 與 V3 版本相容的設定

1. tail -f /var/log/syslog # 可見到下述訊息
   Sep 1 08:31:01 yotta check_nrpe: Remote 192.168.1.108 accepted a Version 2 Packet
   Sep 1 08:31:05 yotta check_nrpe: Remote 192.168.1.101 does not support Version 3 Packets
   Sep 1 08:31:05 yotta check_nrpe: Remote 192.168.1.101 accepted a Version 2 Packet
2. 參考自：'check_nrpe' command definition
3. vim /etc/nagios/object/commands.cfg # 最下面增加下述# Remote 192.168.1.108 does not support Version 3 Packets
   define command {
   command_name check_nrpe_v2
   command_line $USER1$/check_nrpe -2 -H $HOSTADDRESS$ -p 5666 -c $ARG1$
   }

Nagios Remote Client 的架設、設定

Nagios 要監控的機器，需要安裝下述：

• Nagios Plugins # 可以想成是 client，都是 check script
• Nagios NRPE # 監控遠端機器會需要這個套件
• 這兩個套件的安裝步驟與上述都一樣(./configure、make ... 即可)
• 其它設定可參考內部設定檔的範例，或者此篇最上面的連結(Debian、Ubuntu Linux 架設那篇)

相關網頁

• Monitoring Linux Remote Hosts with nagios NRPE...
• Nagios - check host status with NRPE
• Nagios NRPE Addon Installation and Configuration - Debian Clusters
• How To Install Nagios On CentOS 6
• GitHub - NagiosEnterprises/nrpe: NRPE Agent
• NRPE - Nagios Remote Plugin Executor - Nagios Exchange
• How to Monitor Linux Server Using Nagios Core And NRPE
• network monitoring - nagios- nrpe installation error(configure: error: Cannot find ssl libraries)