FEATURE: Allow non-frontend parents to be time servers

Also allow for non management of time

Author: anooprajendra

common/nodes/time-server.xml

@@ -12,6 +12,7 @@ https://github.com/Teradata/stacki/blob/master/LICENSE.txt
 <stack:script stack:stage="install-post">
 /opt/stack/bin/stack set attr attr=time.protocol value=chrony
 /opt/stack/bin/stack set appliance attr frontend attr=time.protocol value=chrony
+/opt/stack/bin/stack set appliance attr frontend attr=time.orphantype value=parent
 /opt/stack/bin/stack report host time &hostname; | /opt/stack/bin/stack report script | sh
 </stack:script>
 </stack:stack> 

common/src/stack/command/stack/commands/report/host/time/__init__.py

@@ -12,51 +12,91 @@
 from stack.exception import *
 
 ## DESIGN CONSIDERATIONS
-# The NTP system set up by default in Stacki has the
+# The timekeeping system set up by default in Stacki has the
 # following design considerations.
 #
-# 1. The Frontend syncs its own time from external servers. - stored in time.servers attribute
-# 2. The Frontend serves NTP to all backends on all networks that are PXE enabled.
-# 3. By default, the Backends sync time from the frontend.
+# 1. All servers in the cluster, can sync times from 2 sources. Any external server
+#    specified in the time.servers attribute, and any servers with time.orphantype value
+#    set to "parent"
+# 2. By default, the frontend is configured as a parent, and can serve time to the rest
+#    of the cluster.
+# 3. time.servers attribute should ideally be set for the frontend, so that it can pick
+#    up
 # 4. If the time.servers attribute is set for a backend host,
 #    then those servers are appended to the list of servers to
 #    sync from.
 # 5. If certain nodes are set as parent servers, they can form a time island, from which
 #    all other servers can sync
+# 6. If Stacki shouldn't be managing time at all, then the time.protocol attribute can
+#    be unset, and the admin can manage the time by themselves
 
 class Command(stack.commands.HostArgumentProcessor,
 	stack.commands.NetworkArgumentProcessor,
 	stack.commands.report.command):
 	"""
 	Create a time configuration report (NTP or chrony).
+	At a minimum at least one server in the cluster has to be designated as a "parent"
+	time server. This ensures that there's atleast one server in the cluster that can
+	serve time. By default, the stacki frontend is a parent timekeeper.
+	Ideally, a "parent" time server will also have the "time.servers" attribute set
+	to talk to an external time server, so that the cluster is in sync with the external
+	time-keeping entity.
 
 	Relevant Attributes:
 
 	time.servers -	Optional - Comma-separated list of servers (IP addresses
 			or resolvable names) that dictate the servers to use for time-keeping.
 			This list is in *addition* to the Stacki frontend.
 
-	time.orphantype - Optional - Only the value of "parent" affects the behaviour
-			if the NTP service. If a host is designated as a parent Orphan-type,
-			that means this host can co-ordinate time with other peers to maintain
+	time.orphantype - Required for at-least one host in the cluster.
+			Only the value of "parent" affects the behaviour
+			of the NTP service. If a host is designated as a
+			parent Orphan-type, that means this host can
+			co-ordinate time with other peers to maintain
 			time on the time island.
 
 	time.protocol - Optional - Can take the value of "chrony" or "ntp". Default
-			Stacki behaviour is to use chrony for the hosts.
+			Stacki behaviour is to use chrony for all hosts, except SLES 11 hosts.
+			SLES 11 hosts use NTP by default
 
 	<arg optional='0' type='string' name='host'>
 	Host name of machine
 	</arg>
 	
 	<example cmd='report host time backend-0-0'>
 	Create a time configuration file for backend-0-0.
+
+	*Configuration*
+	Scenario 1: Use Frontend for time keeping
+	If the desired behavior is to use the frontend as the primary, and only time server,
+	no configuration changes have to be made in Stacki. This is the default behavior.
+
+	Scenario 2: Use frontend for time keeping, in sync with an external time server.
+	Set time.servers attribute on the frontend to the IP Address, or Hostname of an external time server.
+	This will set the frontend to sync time against an external time server, and all other hosts to
+	sync time from the frontend.
+
+	Scenario 3: Sync time on all hosts using an external time server only.
+	Unset the frontend appliance attribute of time.orphantype. This will disable the frontend
+	from serving time.
+	Set the time.servers attribute for all hosts to the IP address, or Hostname of external
+	time server. This will require that all hosts can contact, and connect to the external time
+	server.
+
+	Scenario 4: Sync time on some hosts from external time servers, and create a time island.
+	Set some of the hosts' time.orphantype attribute to parent. Then set those hosts' time.servers
+	attribute to the IP address, or Hostname of external time server. The list of parent time servers
+	can include the frontend or not.
+
+	Scenario 5: Don't use Stacki to sync time.
+	To do this, make sure that the time.protocol attribute is not set for a host or a set of hosts.
 	</example>
 	"""
 
 	def getNTPPeers(self, host):
 
 		peerlist = []
-		parents = [ h for h in self.attrs if ( self.attrs[h].get('time.orphantype') == 'parent' and h != host and h != self.frontend ) ]
+		parents = [ h for h in self.attrs if ( self.attrs[h].get('time.orphantype') == 'parent' and h != host) ]
 		if parents:
 			op = self.call('list.host.interface', parents + ['expanded=true'])
 			networks = self.getNTPNetworkNames(host)
@@ -65,6 +105,7 @@ def getNTPPeers(self, host):
 			for i in n:
 				if i not in peerlist:
 					peerlist.append(i)
+
 		return peerlist
 
 	def getNTPNetworkNames(self, host):
@@ -82,7 +123,8 @@ def getNTPNetworkNames(self, host):
 		if ntp_net_extra:
 			for net in ntp_net_extra.split(','):
 				if net not in stacki_networks:
-					raise CommandError(self, f"Network {net} is unknown to Stacki. Fix 'time.networks' attribute for host {host}")
+					raise CommandError(self, f"Network {net} is unknown to Stacki\n" + \
+						"Fix 'time.networks' attribute for host {host}")
 				networks.append(net)
 		return networks
 
@@ -103,20 +145,11 @@ def getNTPServers(self, host):
 		if timeservers:
 			timeservers = timeservers.split(",")
 
-		if self.appliance == 'frontend':
-			if not timeservers:
-				timeservers = [self.attrs[host].get('Kickstart_PublicNTPHost')]
-		else:
-			n = []
-			output = self.call('list.host.interface', [ host , 'expanded=true'])
-			for o in output:
-				if o['network'] in self.frontend_ntp_addrs:
-					n.append(self.frontend_ntp_addrs[o['network']])
-			if not timeservers:
-				timeservers = n
-			else:
-				timeservers = n + timeservers
+		if not timeservers:
+			timeservers = []
 
+		for peer in self.getNTPPeers(host):
+			timeservers.append(peer)
 		return timeservers
 
 	def set_timezone(self, host):
@@ -163,12 +196,17 @@ def run(self, params, args):
 			self.appliance  = self.attrs[host].get('appliance')
 			self.osversion  = self.attrs[host].get('os.version')
 
+			if protocol == None:
+				continue
+
 			if self.osversion == '11.x':
 				protocol = 'ntp'
 
 			self.timeservers = self.getNTPServers(host)
 			if len(self.timeservers) == 0:
-				raise CommandError(self, f'No time servers specified for host {host}. Check network interface assignments')
+				if not 'time.orphantype' in self.attrs[host] or not self.attrs[host]['time.orphantype'] == 'parent':
+					raise CommandError(self, f'No time servers specified for host {host}\n' +
+						'Check time.* attributes, and network interface assignments')
 
 			self.runImplementation('time_%s' % protocol, (host))
 

common/src/stack/command/stack/commands/report/host/time/imp_time_chrony.py

@@ -93,7 +93,8 @@ def run(self, host):
 		else:
 			self.client(host)
 
-		self.owner.addOutput(host, "/usr/sbin/chronyd -q 'server %s iburst'" % self.owner.timeservers[0])
+		if self.owner.timeservers:
+			self.owner.addOutput(host, "/usr/sbin/chronyd -q 'server %s iburst'" % self.owner.timeservers[0])
 
 		self.owner.addOutput(host, "systemctl enable chronyd")
 		self.owner.addOutput(host, 'systemctl start chronyd')

common/src/stack/command/stack/commands/report/host/time/imp_time_ntp.py

@@ -125,7 +125,8 @@ def run(self, host):
 		#
 		# set the clock right now
 		#
-		self.owner.addOutput(host, '/usr/sbin/ntpdate %s' % self.owner.timeservers[0])
+		if self.owner.timeservers:
+			self.owner.addOutput(host, '/usr/sbin/ntpdate %s' % self.owner.timeservers[0])
 		# Restart the NTPD service
 		if self.owner.osversion == '11.x':
 			self.owner.addOutput(host, 'service ntp start')