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Integrate netdata monitor (on Linux server)

What's netdata

netdata (http://my-netdata.io) is a "Simple. Effective. Awesome!" monitor which can monitor almost everyting on your Linux/FreeBSD system. You can visit its website to check online demo.

We will show you how to install and configure netdata on iRedMail server (Linux) to monitor mail service related softwares.

Install packages required by netdata

netdata requires some tools to get stastics data from other softwares, let's install it first.

• On RHEL/CentOS:

yum install curl libmnl libuuid lm_sensors nc PyYAML zlib iproute MySQL-python python-psycopg2

• On Debian/Ubuntu:

apt-get install zlib1g libuuid1 libmnl0 curl lm-sensors iproute netcat python-mysqldb python-psycopg2

Install netdata

• Download the latest netdata from its github project page, and upload to iRedMail server: https://github.com/firehol/netdata/releases

  We use version 1.9.0 for example in this tutorial, the package we download is: https://github.com/firehol/netdata/releases/download/v1.9.0/netdata-latest.gz.run

  We assume you upload the package to /root/netdata-latest.gz.run.

• Install netdata:

cd /root/
chmod +x netdata-latest.gz.run
./netdata-latest.gz.run --accept

netdata installs its files under /opt/netdata/ by default, let's create symbol link of the configuration and log directories:

ln -s /opt/netdata/etc/netdata /etc/netdata
ln -s /opt/netdata/var/log/netdata /var/log/netdata

netdata will create required systemd script for service control, also logrotate config file, so there's not much we need to do after the package installation.

Configure netdata

Main config file of netdata is /etc/netdata/netdata.conf, it contains many parameters with detailed comments. Here's the config file used by iRedMail:

• It binds to address 127.0.0.1 and port 19999 by default. Since it doesn't have ACL control, we will run netdata behind Nginx to get ACL control done in Nginx.

[registry]
    enabled = no

[global]
    bind to = 127.0.0.1
    run as user = netdata
    default port = 19999
    update every = 3

[plugin:proc]
    # Disable IPVS check since iRedMail doesn't use ipvs by default
    /proc/net/ip_vs/stats = no

    # inbound packets dropped
    /proc/net/dev = no

netdata ships a lot modular config files to gather information of softwares running on the server, they have very good default settings and most config files don't need your attention at all. but some applications do require extra settings.

Monitor Nginx and php-fpm

We need to enable stub_status in Nginx to get detailed server info, also update php-fpm config file to enable similar feature.

• Create Nginx config snippet /etc/nginx/templates/stub_status.tmpl with content below:

location = /stub_status {
    stub_status on;
    access_log off;
    allow 127.0.0.1;
    deny all;
}

location = /status {
    include fastcgi_params;
    fastcgi_pass php_workers;
    fastcgi_param SCRIPT_FILENAME $fastcgi_script_name;
    access_log off;
    allow 127.0.0.1;
    deny all;
}

• Update default virtual host config file /etc/nginx/sites-enabled/00-default.conf, include new snippet config file stub_status.tmpl after the redirect_to_https.tmpl line like below:

server {
    ...
    include /etc/nginx/templates/redirect_to_https.tmpl;
    include /etc/nginx/templates/stub_status.tmpl;      # <- add this line
    ...
}

• Update php-fpm pool config file www.conf, enable parameter pm.status_path like below:
  • On RHEL/CentOS, it's /etc/php-fpm.d/www.conf
  • On Debian, it's /etc/php5/fpm/pool.d/www.conf
  • On Ubuntu, it's /etc/php/7.0/fpm/pool.d/www.conf (note: php version number may be different on your server)
  • On FreeBSD, it's /usr/local/etc/php-fpm.d/www.conf
  • On OpenBSD, it's /etc/php-fpm.conf

pm.status_path = /status

• Restart both php-fpm and Nginx service.

[TODO] Monitor Dovecot

Monitor MySQL/MariaDB server

netdata requires a SQL user (we use netdata here) with privilege USAGE to gather MySQL server information.

• Create the SQL user with a strong password (please replace <password> in command below by the real (and strong) password).

# mysql -u root
sql> GRANT USAGE ON *.* TO netdata@localhost IDENTIFIED BY '<password>';
sql> FLUSH PRIVILEGES;

• Create file /etc/netdata/python.d/mysql.conf with content below.

  Attention

  • This file already exists, feel free to remove all content in this file and copy content below as its new content.
  • Please replace <password> below by the real password.

tcp:
    name: 'local'
    host: '127.0.0.1'
    port: '3306'
    user: 'netdata'
    pass: '<password>'

Monitor PostgreSQL server

netdata requires a SQL user (we use netdata here) to gather PostgreSQL server information.

• Create the SQL user with a strong password (please replace <password> in command below by the real (and strong) password).

# su - postgres
$ psql
sql> CREATE USER netdata WITH ENCRYPTED PASSWORD '<password>' NOSUPERUSER NOCREATEDB NOCREATEROLE;

• Create file /etc/netdata/python.d/mysql.conf with content below.

  Attention

  • This file already exists, feel free to remove all content in this file and copy content below as its new content.
  • Please replace <password> below by the real password.

socket:
    name     : 'local'
    user     : 'netdata'
    password : '<password>'
    database : 'postgres'

Configure Nginx to forward requests to netdata

System tuning

To get better performance, netdata requires few sysctl settings. Please add lines below in /etc/sysctl.conf:

vm.dirty_expire_centisecs=60000
vm.dirty_background_ratio=80
vm.dirty_ratio=90

Also increase max open files limit.

mkdir -p /etc/systemd/system/netdata.service.d

Create file /etc/systemd/system/netdata.service.d/limits.conf:

[Service]
LimitNOFILE=30000

Reload systemd daemon:

systemctl daemon-reload