icinga2/doc/3.05-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
configuration:

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

      check = "ping"
    }

    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. Each host gets its own host `check` defined as the `ping`
service too.

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" ]
      }
    }