mirror of https://github.com/Icinga/icinga2.git
44 lines
1.6 KiB
Markdown
44 lines
1.6 KiB
Markdown
## <a id="dependencies"></a> Dependencies
|
|
|
|
Icinga 2 uses host and service [Dependency](#objecttype-dependency) objects either directly
|
|
defined or as inline definition as `dependencies` dictionary. The `parent_host_name` and `parent_service_name`
|
|
attributes are mandatory.
|
|
|
|
A service can depend on a host, and vice versa. A service has an implicit dependency (parent)
|
|
to its host. A host to host dependency acts implicit as host parent relation.
|
|
When dependencies are calculated, not only the immediate parent is taken into
|
|
account but all parents are inherited.
|
|
|
|
A common scenario is the Icinga 2 server behind a router. Checking internet
|
|
access by pinging the Google DNS server `google-dns` is a common method, but
|
|
will fail in case the `dsl-router` host is down. Therefore the example below
|
|
defines a host dependency which acts implicit as parent relation too.
|
|
|
|
Furthermore the host may be reachable but ping probes are dropped by the
|
|
router's firewall. In case the `dsl-router``ping4` service check fails, all
|
|
further checks for the `ping4` service on host `google-dns` service should
|
|
be suppressed. This is achieved by setting the `disable_checks` attribute to `true`.
|
|
|
|
object Host "dsl-router" {
|
|
address = "192.168.1.1"
|
|
}
|
|
|
|
object Host "google-dns" {
|
|
address = "8.8.8.8"
|
|
}
|
|
|
|
apply Service "ping4" {
|
|
import "generic-service"
|
|
|
|
check_command = "ping4"
|
|
|
|
assign where host.address
|
|
}
|
|
|
|
apply Dependency "internet" to Service {
|
|
parent_host_name = "dsl-router"
|
|
disable_checks = true
|
|
|
|
assign where host.name != "dsl-router"
|
|
}
|