How To Add Remote Linux Machines into Icinga 2 Server

Setup Master with Clients

On the master node, create a new configuration directory using the following command.

mkdir -p /etc/icinga2/zones.d/master

We will now define the client nodes and apply service checks using the command endpoint execution method on them.

centos.itzgeek.local:

vi /etc/icinga2/zones.d/master/centos.itzgeek.local.conf

Add the following in the above file.

// Endpoints & Zones
object Endpoint "centos.itzgeek.local" {
}
object Zone "centos.itzgeek.local" {
     endpoints = [ "centos.itzgeek.local" ]
     parent = "master"
}
// Host Objects
object Host "centos.itzgeek.local" {
    check_command = "hostalive"
    address = "192.168.1.20"
    vars.client_endpoint = name //follows the convention that host name == endpoint name
// Custom Optional check - START
    vars.local_disks["/app Filesystem"] = {
       disk_partitions = "/app"
  }
    vars.local_http_vhosts["http"] = {
       http_uri = "/"
  }
    vars.local_tcp_port["tcp"] ={
       tcp_port = "23"
       service_name = "Telnet Check"
       port_number = "Port 23"
  }
// Custom Optional Check - END
}

Ubuntu.itzgeek.local:

vi /etc/icinga2/zones.d/master/ubuntu.itzgeek.local.conf

Simple monitoring check for Ubuntu.

// Endpoints & Zones
object Endpoint "ubuntu.itzgeek.local" {
}
object Zone "ubuntu.itzgeek.local" {
     endpoints = [ "ubuntu.itzgeek.local" ]
     parent = "master"
}
// Host Objects
object Host "ubuntu.itzgeek.local" {
    check_command = "hostalive"
    address = "192.168.1.30"
    vars.client_endpoint = name //follows the convention that host name == endpoint name
}

Since we have disabled inclusion of the conf.d directory during the setup icinga2 node wizard, we have to add services using command endpoint checks.

vi /etc/icinga2/zones.d/master/services.conf

Add the following basic services and few custom services.

// Ping Check
apply Service "Ping" {
  check_command = "ping4"
  assign where host.address // check is executed on the master node
}
// System Load
apply Service "System Load" {
  check_command = "load"
  command_endpoint = host.vars.client_endpoint // Check executed on client node
  assign where host.vars.client_endpoint
}
// System Process Count
apply Service "Process" {
  check_command = "procs"
  command_endpoint = host.vars.client_endpoint
  assign where host.vars.client_endpoint
}
// Logged in User Count
apply Service "Users" {
  check_command = "users"
  command_endpoint = host.vars.client_endpoint
  assign where host.vars.client_endpoint
}
// Disk Usage Check
apply Service "Disk" {
  check_command = "disk"
  command_endpoint = host.vars.client_endpoint
  assign where host.vars.client_endpoint
}
// Disk Usage Check for Specific Partition
apply Service for (disk => config in host.vars.local_disks) {
  check_command = "disk"
  vars += config
  command_endpoint = host.vars.client_endpoint
  assign where host.vars.client_endpoint
}
// System Swap Check
apply Service "SWAP" {
  check_command = "swap"
  command_endpoint = host.vars.client_endpoint
  assign where host.vars.client_endpoint
}
// SSH Service Check
apply Service "SSH Service" {
  check_command = "ssh"
  command_endpoint = host.vars.client_endpoint
  assign where host.vars.client_endpoint
}
// FTP Service Check
apply Service "FTP Service" {
  check_command = "ftp"
  command_endpoint = host.vars.client_endpoint
  assign where host.vars.client_endpoint
}
// Icinga 2 Service Check
apply Service "Icinga2 Service" {
  check_command = "icinga"
  command_endpoint = host.vars.client_endpoint
  assign where host.vars.client_endpoint
}
// Apache VirtualHost Check
apply Service for (http_vhost => config in host.vars.local_http_vhosts) {
  check_command = "http"
  vars += config
  command_endpoint = host.vars.client_endpoint
  assign where host.vars.client_endpoint
}
// TCP Port Check
apply Service for (tcp_port => config in host.vars.local_tcp_port) {
  check_command = "tcp"
  vars += config
  display_name = + vars.service_name + " - " + vars.port_number
  command_endpoint = host.vars.client_endpoint
  assign where host.vars.client_endpoint
}

You can read more about service monitoring here.

Validate the configuration.

icinga2 daemon -C

Restart Icinga 2 on the master node.

### For Systemd Systems ###
systemctl restart icinga2

### For SysVinit Systems ###
service icinga2 restart

Monitor Remote Linux Machines with Icinga 2

Now, you should be able to see both machines in Icinga Web 2 dashboard.

Dashboard >> Overview >> Hosts.

Click on the client machine to get the details of a particular node.

You can click on Services tab to see the status of checked services.

centos.itzgeek.local:

ubuntu.itzgeek.local:

Hope this article series helped you to setup Icinga 2 on your environment.

That’s All.