1 . 監視対象サーバ Munin インストール

$ sudo apt-get install munin-node

2 . 監視対象サーバ設定

監視サーバアドレス 192.168.1.1 の例

$ sudo vi /etc/munin/munin-node.conf
allow ^192\.168\.1\.1$
$ sudo systemctl restart munin-node.service
$ sudo systemctl enable munin-node.service
$ sudo ufw allow from 192.168.1.1 to any port 4949

3 . 監視対象サーバ Nginx 設定

$ sudo vi /etc/nginx/sites-available/default
    location /nginx_status {
        stub_status on;
        access_log off;
        allow 127.0.0.1;
        allow ::1;
        deny all;
    }
$ sudo nginx -t && sudo nginx -s reload
$ curl http://localhost/nginx_status
Active connections: 1
server accepts handled requests
 1323 1323 2600
Reading: 0 Writing: 1 Waiting: 0
$ cd /etc/munin/plugins
$ sudo ln -s /usr/share/munin/plugins/nginx_request
$ sudo ln -s /usr/share/munin/plugins/nginx_status
$ sudo vi /etc/munin/plugin-conf.d/munin-node
[nginx*]
env.url http://localhost/nginx_status
$ sudo /etc/init.d/munin-node restart
$ tail /var/log/munin/munin-node.log

4 . 監視サーバ Munin インストール

$ sudo apt-get install munin munin-node spawn-fcgi

5 . 監視サーバ設定

$ sudo vi /etc/munin/munin.conf
dbdir   /var/lib/munin
htmldir /var/www/html/munin
logdir /var/log/munin
rundir  /var/run/munin
$ sudo /etc/init.d/munin restart
$ sudo /etc/init.d/munin-node restart
$ sudo -u munin munin-cron

6 . 監視サーバ Nginx 設定

$ sudo vi /etc/nginx/sites-available/munin.example.com
server {
        listen         80;
        listen    [::]:80;

        root /var/cache/munin/www/;
        index index.php index.html;
        server_name munin.example.com;
}
$ sudo ln -s /etc/nginx/sites-available/munin.example.com /etc/nginx/sites-enabled/
$ sudo nginx -t && sudo nginx -s reload

7 . 監視画面

ブラウザで http://munin.example.com へアクセス

8 . プラグイン状況確認

$ sudo munin-node-configure -suggest
Plugin                     | Used | Suggestions
------                     | ---- | -----------
acpi                       | no   | no [failed to find thermal zones below /sys/class/thermal/thermal_zone*]
amavis                     | no   | no
apache_accesses            | no   | no [LWP::UserAgent not found]
...