Add more basic checks, including for mail

roles/icinga2_master/templates/zones.d/master/services.conf.j2

@@ -71,3 +71,39 @@ apply Service "users" {
     command_endpoint = host.name
     assign where true
 }
+
+apply Service "ntp" {
+    import "generic-service"
+    check_command = "ntp_time"
+    command_endpoint = host.name
+    assign where true
+}
+
+apply Service "mailq" {
+    import "generic-service"
+    check_command = "mailq"
+    command_endpoint = host.name
+    assign where true
+    vars.mailq_warning = 10
+    vars.mailq_critical = 20
+}
+
+apply Service "smtp" {
+    import "generic-service"
+    check_command = "smtp"
+    assign where host.name == "{{ relayhost }}"
+}
+
+apply Service "submission" {
+    import "generic-service"
+    check_command = "smtp"
+    assign where host.name == "{{ relayhost }}"
+    vars.smtp_port = 587
+    vars.smtp_starttls = true
+}
+
+apply Service "imaps" {
+    import "generic-service"
+    check_command = "simap"
+    assign where host.name == "{{ relayhost }}"
+}