Add CheckCommand "dns"

Refs #6487

Author: gvegidy

doc/6-configuring-icinga-2.md

@@ -2079,6 +2079,19 @@ snmp_community  | **Optional.** The SNMP community. Defaults to "public".
 
 #### <a id="plugin-check-command-dhcp"></a> dhcp
 
+Check command object for the `check_dns` plugin.
+
+Custom Attributes:
+
+Name                 | Description
+---------------------|--------------
+dns_lookup           | **Optional.** The hostname or IP to query the dns for. Defaults to $host_name$.
+dns_server           | **Optional.** The DNS server to query. Defaults to the server configured in the OS.
+dns_expected_answer  | **Optional.** The answer to look for. A hostname must end with a dot.
+dns_authorative      | **Optional.** Expect the server to send an authorative answer.
+
+#### <a id="plugin-check-command-dns"></a> dns
+
 Check command object for the `check_dhcp` plugin.
 
 Custom Attributes:

itl/command-plugins.conf

@@ -423,6 +423,24 @@ object CheckCommand "dhcp" {
 	vars.dhcp_unicast = false
 }
 
+object CheckCommand "dns" {
+	import "plugin-check-command"
+
+	command = PluginDir + "/check_dns"
+
+	arguments = {
+		"-H" = "$dns_lookup$",
+		"-s" = "$dns_server$",
+		"-a" = "$dns_expected_answer$",
+		"-A" = {
+			set_if = "$dns_authorative$"
+		}
+	}
+
+	vars.dns_lookup = "$host_name$"
+	vars.dns_expected_answer = "$address$"
+}
+
 object CheckCommand "nscp" {
 	import "plugin-check-command"