fix(ntp): use `pool` instead of `server` directive

2.Common_services/2.NTP/0_setup.py

@@ -9,9 +9,9 @@ def setup(interactive=True):
     if utils.get_conf('NTP_SERVER'):
         for server in utils.get_conf('NTP_SERVER').split(','):
             if server.strip():
-                servers += 'server %s\n' % server.strip()
+                servers += 'pool %s\n' % server.strip()
     if not servers:
-        servers = 'server ntp.ubuntu.com\n'
+        servers = 'pool ntp.ubuntu.com\n'
     cmds = [
         # NTP
         'DEBIAN_FRONTEND=noninteractive apt-get install -y ntp',
@@ -19,6 +19,6 @@ def setup(interactive=True):
         dict(line='write', template='%s/ntp.conf' % dir_path, target='/etc/ntp.conf', params=(
             ('{{ servers }}', servers),
         )),
-        'service ntp restart',
+        'systemctl restart ntp.service',
     ]
     utils.run_commands(cmds)