Use timedatectl to enable/disable ntp

Command timedatectl is used to set server time. However, if
disable chronyd before set_servertime by systemctl, timedatectl
may not sync the status in time, then the set-time will fail as
`Failed to set time: Automatic time synchronization is enabled`.
This is because systemd checks synchronization status periodically
and update its own NTP flag (which is timedatectl replied on)
To let timedatectl update NTP flag instantly, use timedatectl
set-ntp true/false to enable/disable the NTP.

Signed-off-by: Changlei Li <changlei.li@cloud.com>

Author: changlei-li

ocaml/xapi/xapi_host_ntp.ml

@@ -72,16 +72,17 @@ let remove_dhcp_ntp_servers () =
            Sys.remove (!Xapi_globs.ntp_dhcp_dir // fname)
      )
 
-let restart_ntp_service () =
-  Xapi_systemctl.restart ~wait_until_success:false !Xapi_globs.ntp_service
-
 let enable_ntp_service () =
-  Xapi_systemctl.enable ~wait_until_success:false !Xapi_globs.ntp_service ;
-  Xapi_systemctl.start ~wait_until_success:false !Xapi_globs.ntp_service
+  Helpers.call_script !Xapi_globs.timedatectl ["set-ntp"; "true"] |> ignore
 
 let disable_ntp_service () =
-  Xapi_systemctl.stop ~wait_until_success:false !Xapi_globs.ntp_service ;
-  Xapi_systemctl.disable ~wait_until_success:false !Xapi_globs.ntp_service
+  Helpers.call_script !Xapi_globs.timedatectl ["set-ntp"; "false"] |> ignore
+
+let restart_ntp_service () =
+  (* Make sure the NTP service is enabled before restarting, and the timedatectl
+     ntp enabled status is consistent with the service state *)
+  enable_ntp_service () ;
+  Xapi_systemctl.restart ~wait_until_success:false !Xapi_globs.ntp_service
 
 let is_ntp_service_active () =
   Fe_systemctl.is_active ~service:!Xapi_globs.ntp_service

ocaml/xapi/xapi_host_ntp.mli

@@ -22,12 +22,12 @@ val clear_servers_in_conf : unit -> unit
 
 val promote_legacy_default_servers : unit -> unit
 
-val restart_ntp_service : unit -> unit
-
 val enable_ntp_service : unit -> unit
 
 val disable_ntp_service : unit -> unit
 
+val restart_ntp_service : unit -> unit
+
 val is_ntp_service_active : unit -> bool
 
 val get_servers_from_conf : unit -> string list