icinga2/doc/3.5-using-templates.md

Using Templates

Templates may be used to apply a set of similar settings to more than one object.

For example, rather than manually creating a ping service object for each of your hosts you can use templates to avoid having to copy & paste parts of your config:

template Host "linux-server" {
  services["ping"] = {
    check_command = "ping4"
  },

  check = "ping4"
}

object Host "my-server1" inherits "linux-server" {
  macros["address"] = "10.0.0.1"
}

object Host "my-server2" inherits "linux-server" {
  macros["address"] = "10.0.0.2"
}

In this example both my-server1 and my-server2 each get their own ping service check.

Objects as well as templates themselves can inherit from an arbitrary number of templates. Attributes inherited from a template can be overridden in the object if necessary.

Templates can also be used in service and notification definitions using the templates attribute:

template Service "weekend-service" {
  check_interval = 0.5m,
  check_period = "weekend"
}

object Host "my-server1" {
  services["backup"] {
    check_command = "backup-check",

templates = [ "weekend-service" ]
  }
}