[5 Mins Docker] Install Open Source System and Network Monitoring Application – Nagios Core

sudo bash -c 'echo "SystemMaxUse=100M" >> /etc/systemd/journald.conf'
sudo systemctl restart systemd-journald

sudo sh -c 'truncate -s 0 /var/lib/docker/containers/*/*-json.log'

cat > /etc/docker/daemon.json << EOF
{
    "log-driver": "json-file",
    "log-opts": {
        "max-size": "20m",
        "max-file": "3"
    },
    "ipv6": true,
    "fixed-cidr-v6": "fd00:dead:beef:c0::/80",
    "eixperimental":true,
    "ip6tables":true
}
EOF

cat <<EOF > /etc/docker/daemon.json
{
  "live-restore": true,
  "storage-driver": "overlay2",
  "log-opts": {
    "max-size": "10m"
  }
}
EOF

systemctl restart docker

Limit number of log files:

cat /etc/logrotate.d/rsyslog

/var/log/syslog
/var/log/mail.info
/var/log/mail.warn
/var/log/mail.err
/var/log/mail.log
/var/log/daemon.log
/var/log/kern.log
/var/log/auth.log
/var/log/user.log
/var/log/lpr.log
/var/log/cron.log
/var/log/debug
/var/log/messages
{
    rotate 4
    weekly
    missingok
    notifempty
    compress
    delaycompress
    sharedscripts
    postrotate
        /usr/lib/rsyslog/rsyslog-rotate
    endscript
}

You can change 4 to some other value, such as 1, so that only one file is stored.

cfg_dir=/opt/nagios/etc/servers

mkdir /opt/nagios/etc/servers

nano /opt/nagios/etc/servers/servers.cfg

define host {
    use                      linux-server
    host_name                DNS01
    alias                    DNS01
    address                  8.8.8.8
    max_check_attempts       5
    check_period             24x7
    notification_interval    30
    notification_period      24x7
}
define service {
    use                    generic-service
    host_name              DNS01
    service_description    PING
    check_command          check_ping!100.0,20%!500.0,60%
}

define service {
    use                      generic-service
    host_name                DNS01
    service_description      SSH
    check_command            check_ssh
    notifications_enabled    1
}

define service {
    use                      generic-service
    host_name                DNS01
    service_description      HTTP
    check_command            check_http
    notifications_enabled    1
}

nagios -v /opt/nagios/etc/nagios.cfg

Docker restart nagios4

Manual install Nagios

sudo apt-get update
sudo apt-get install -y autoconf gcc libc6 make wget unzip apache2 php libapache2-mod-php7.4 libgd-dev

sudo apt-get install openssl libssl-dev

Donload Nagios Core

cd /tmp
wget -O nagioscore.tar.gz https://github.com/NagiosEnterprises/nagioscore/archive/nagios-4.4.14.tar.gz
tar xzf nagioscore.tar.gz

Check the releases page for latest Nagios available.

NAGIOS_VER=$(curl -s https://api.github.com/repos/NagiosEnterprises/nagioscore/releases/latest|grep tag_name|cut -d '"' -f 4)
curl -SL https://github.com/NagiosEnterprises/nagioscore/releases/download/$NAGIOS_VER/$NAGIOS_VER.tar.gz | tar -xzf -

The command will download and extract the Nagios core archive to your current working directory.

Compile

Change to created Nagios folder.

cd $NAGIOS_VER

cd /tmp/nagioscore-nagios-4.4.14/
sudo ./configure --with-httpd-conf=/etc/apache2/sites-enabled
sudo make all

Create User And Group

This creates the nagios user and group. The www-data user is also added to the nagios group.

sudo make install-groups-users
sudo usermod -a -G nagios www-data

Install Binaries

This step installs the binary files, CGIs, and HTML files.

sudo make install

Install Service / Daemon

This installs the service or daemon files and also configures them to start on boot.

sudo make install-daemoninit

Information on starting and stopping services will be explained further on.

Install Command Mode

This installs and configures the external command file.

sudo make install-commandmode

Install Configuration Files

This installs the *SAMPLE* configuration files. These are required as Nagios needs some configuration files to allow it to start.

sudo make install-config

Install Apache Config Files

This installs the Apache web server configuration files and configures Apache settings.

sudo make install-webconf
sudo a2enmod rewrite
sudo a2enmod cgi

Install the Exfoliation theme for the Nagios web interface.

sudo make install-exfoliation

If you want to use classic Nagios theme, run:

make install-classicui

Create Nagios Web User

A user is required for the access to Nagios web console.

$ sudo htpasswd -c /usr/local/nagios/etc/htpasswd.users nagiosadmin
New password: 
Re-type new password: 
Adding password for user nagiosadmin

The htpasswd has been used to generate the password and write it to the /usr/local/nagios/etc/htpasswd.users file.

Install Nagios Plugins

Nagios plugins are used to extend Nagios monitoring features. Let’s ensure they are installed. Check for the latest release of Nagios plugins from Github releases page.

cd ~/
VER=$( curl -s https://api.github.com/repos/nagios-plugins/nagios-plugins/releases/latest|grep tag_name|cut -d '"' -f 4|sed 's/release-//')
curl -SL https://github.com/nagios-plugins/nagios-plugins/releases/download/release-$VER/nagios-plugins-$VER.tar.gz | tar -xzf -

Change to the plugins source directory:

cd nagios-plugins-$VER

Compile and install Nagios plugins by running commands below.

./configure --with-nagios-user=nagios --with-nagios-group=nagios
make
sudo make install

Verify installation and start service

Confirm that your Nagios installation was successful on Ubuntu Linux machine.

sudo /usr/local/nagios/bin/nagios -v /usr/local/nagios/etc/nagios.cfg

Start and enable nagios service to start at boot.

sudo systemctl  enable --now nagios

References