13804: Try to cancel pending shutdowns if nodes are needed
[arvados.git] / services / nodemanager / arvnodeman / computenode / dispatch / __init__.py
index 3c708778d0c274b17c0d9c2c42b8c0b768da331b..bb83a193fa30bae46dc7a7f6979843eb65fd42d1 100644 (file)
@@ -1,80 +1,62 @@
 #!/usr/bin/env python
+# Copyright (C) The Arvados Authors. All rights reserved.
+#
+# SPDX-License-Identifier: AGPL-3.0
 
 from __future__ import absolute_import, print_function
 
 import functools
 import logging
 import time
+import re
 
 import libcloud.common.types as cloud_types
+from libcloud.common.exceptions import BaseHTTPError
+
 import pykka
 
 from .. import \
-    arvados_node_fqdn, arvados_node_mtime, arvados_timestamp, timestamp_fresh, arvados_node_missing
+    arvados_node_fqdn, arvados_node_mtime, arvados_timestamp, timestamp_fresh, \
+    arvados_node_missing, RetryMixin
 from ...clientactor import _notify_subscribers
 from ... import config
+from ... import status
+from .transitions import transitions
+
+QuotaExceeded = "QuotaExceeded"
 
-class ComputeNodeStateChangeBase(config.actor_class):
+class ComputeNodeStateChangeBase(config.actor_class, RetryMixin):
     """Base class for actors that change a compute node's state.
 
     This base class takes care of retrying changes and notifying
     subscribers when the change is finished.
     """
-    def __init__(self, logger_name, cloud_client, arvados_client, timer_actor,
+    def __init__(self, cloud_client, arvados_client, timer_actor,
                  retry_wait, max_retry_wait):
         super(ComputeNodeStateChangeBase, self).__init__()
-        self._later = self.actor_ref.proxy()
-        self._logger = logging.getLogger(logger_name)
-        self._cloud = cloud_client
+        RetryMixin.__init__(self, retry_wait, max_retry_wait,
+                            None, cloud_client, timer_actor)
+        self._later = self.actor_ref.tell_proxy()
         self._arvados = arvados_client
-        self._timer = timer_actor
-        self.min_retry_wait = retry_wait
-        self.max_retry_wait = max_retry_wait
-        self.retry_wait = retry_wait
         self.subscribers = set()
 
-    @staticmethod
-    def _retry(errors=()):
-        """Retry decorator for an actor method that makes remote requests.
-
-        Use this function to decorator an actor method, and pass in a
-        tuple of exceptions to catch.  This decorator will schedule
-        retries of that method with exponential backoff if the
-        original method raises a known cloud driver error, or any of the
-        given exception types.
-        """
-        def decorator(orig_func):
-            @functools.wraps(orig_func)
-            def retry_wrapper(self, *args, **kwargs):
-                start_time = time.time()
-                try:
-                    orig_func(self, *args, **kwargs)
-                except Exception as error:
-                    if not (isinstance(error, errors) or
-                            self._cloud.is_cloud_exception(error)):
-                        raise
-                    self._logger.warning(
-                        "Client error: %s - waiting %s seconds",
-                        error, self.retry_wait)
-                    self._timer.schedule(start_time + self.retry_wait,
-                                         getattr(self._later,
-                                                 orig_func.__name__),
-                                         *args, **kwargs)
-                    self.retry_wait = min(self.retry_wait * 2,
-                                          self.max_retry_wait)
-                else:
-                    self.retry_wait = self.min_retry_wait
-            return retry_wrapper
-        return decorator
+    def _set_logger(self):
+        self._logger = logging.getLogger("%s.%s" % (self.__class__.__name__, self.actor_urn[33:]))
+
+    def on_start(self):
+        self._set_logger()
 
     def _finished(self):
-        _notify_subscribers(self._later, self.subscribers)
+        if self.subscribers is None:
+            raise Exception("Actor tried to finish twice")
+        _notify_subscribers(self.actor_ref.proxy(), self.subscribers)
         self.subscribers = None
+        self._logger.info("finished")
 
     def subscribe(self, subscriber):
         if self.subscribers is None:
             try:
-                subscriber(self._later)
+                subscriber(self.actor_ref.proxy())
             except pykka.ActorDeadError:
                 pass
         else:
@@ -88,10 +70,22 @@ class ComputeNodeStateChangeBase(config.actor_class):
                   'slot_number': None,
                   'first_ping_at': None,
                   'last_ping_at': None,
+                  'properties': {},
                   'info': {'ec2_instance_id': None,
                            'last_action': explanation}},
             ).execute()
 
+    @staticmethod
+    def _finish_on_exception(orig_func):
+        @functools.wraps(orig_func)
+        def finish_wrapper(self, *args, **kwargs):
+            try:
+                return orig_func(self, *args, **kwargs)
+            except Exception as error:
+                self._logger.error("Actor error %s", error)
+                self._finished()
+        return finish_wrapper
+
 
 class ComputeNodeSetupActor(ComputeNodeStateChangeBase):
     """Actor to create and set up a cloud compute node.
@@ -106,37 +100,96 @@ class ComputeNodeSetupActor(ComputeNodeStateChangeBase):
                  cloud_size, arvados_node=None,
                  retry_wait=1, max_retry_wait=180):
         super(ComputeNodeSetupActor, self).__init__(
-            'arvnodeman.nodeup', cloud_client, arvados_client, timer_actor,
+            cloud_client, arvados_client, timer_actor,
             retry_wait, max_retry_wait)
         self.cloud_size = cloud_size
         self.arvados_node = None
         self.cloud_node = None
+        self.error = None
         if arvados_node is None:
             self._later.create_arvados_node()
         else:
             self._later.prepare_arvados_node(arvados_node)
 
-    @ComputeNodeStateChangeBase._retry(config.ARVADOS_ERRORS)
+    @ComputeNodeStateChangeBase._finish_on_exception
+    @RetryMixin._retry(config.ARVADOS_ERRORS)
     def create_arvados_node(self):
-        self.arvados_node = self._arvados.nodes().create(body={}).execute()
+        self.arvados_node = self._arvados.nodes().create(
+            body={}, assign_slot=True).execute()
         self._later.create_cloud_node()
 
-    @ComputeNodeStateChangeBase._retry(config.ARVADOS_ERRORS)
+    @ComputeNodeStateChangeBase._finish_on_exception
+    @RetryMixin._retry(config.ARVADOS_ERRORS)
     def prepare_arvados_node(self, node):
-        self.arvados_node = self._clean_arvados_node(
-            node, "Prepared by Node Manager")
+        self._clean_arvados_node(node, "Prepared by Node Manager")
+        self.arvados_node = self._arvados.nodes().update(
+            uuid=node['uuid'], body={}, assign_slot=True).execute()
         self._later.create_cloud_node()
 
-    @ComputeNodeStateChangeBase._retry()
+    @ComputeNodeStateChangeBase._finish_on_exception
+    @RetryMixin._retry()
     def create_cloud_node(self):
-        self._logger.info("Creating cloud node with size %s.",
+        self._logger.info("Sending create_node request for node size %s.",
                           self.cloud_size.name)
-        self.cloud_node = self._cloud.create_node(self.cloud_size,
-                                                  self.arvados_node)
+        try:
+            self.cloud_node = self._cloud.create_node(self.cloud_size,
+                                                      self.arvados_node)
+        except BaseHTTPError as e:
+            if e.code == 429 or "RequestLimitExceeded" in e.message:
+                # Don't consider API rate limits to be quota errors.
+                # re-raise so the Retry logic applies.
+                raise
+
+            # The set of possible error codes / messages isn't documented for
+            # all clouds, so use a keyword heuristic to determine if the
+            # failure is likely due to a quota.
+            if re.search(r'(exceed|quota|limit)', e.message, re.I):
+                self.error = QuotaExceeded
+                self._logger.warning("Quota exceeded: %s", e)
+                self._finished()
+                return
+            else:
+                # Something else happened, re-raise so the Retry logic applies.
+                raise
+        except Exception as e:
+            raise
+
+        # The information included in the node size object we get from libcloud
+        # is inconsistent between cloud drivers.  Replace libcloud NodeSize
+        # object with compatible CloudSizeWrapper object which merges the size
+        # info reported from the cloud with size information from the
+        # configuration file.
+        self.cloud_node.size = self.cloud_size
+
         self._logger.info("Cloud node %s created.", self.cloud_node.id)
+        self._later.update_arvados_node_properties()
+
+    @ComputeNodeStateChangeBase._finish_on_exception
+    @RetryMixin._retry(config.ARVADOS_ERRORS)
+    def update_arvados_node_properties(self):
+        """Tell Arvados some details about the cloud node.
+
+        Currently we only include size/price from our request, which
+        we already knew before create_cloud_node(), but doing it here
+        gives us an opportunity to provide more detail from
+        self.cloud_node, too.
+        """
+        self.arvados_node['properties']['cloud_node'] = {
+            # Note this 'size' is the node size we asked the cloud
+            # driver to create -- not necessarily equal to the size
+            # reported by the cloud driver for the node that was
+            # created.
+            'size': self.cloud_size.id,
+            'price': self.cloud_size.price,
+        }
+        self.arvados_node = self._arvados.nodes().update(
+            uuid=self.arvados_node['uuid'],
+            body={'properties': self.arvados_node['properties']},
+        ).execute()
+        self._logger.info("%s updated properties.", self.arvados_node['uuid'])
         self._later.post_create()
 
-    @ComputeNodeStateChangeBase._retry()
+    @RetryMixin._retry()
     def post_create(self):
         self._cloud.post_create_node(self.cloud_node)
         self._logger.info("%s post-create work done.", self.cloud_node.id)
@@ -156,7 +209,7 @@ class ComputeNodeShutdownActor(ComputeNodeStateChangeBase):
     """
     # Reasons for a shutdown to be cancelled.
     WINDOW_CLOSED = "shutdown window closed"
-    NODE_BROKEN = "cloud failed to shut down broken node"
+    DESTROY_FAILED = "destroy_node failed"
 
     def __init__(self, timer_actor, cloud_client, arvados_client, node_monitor,
                  cancellable=True, retry_wait=1, max_retry_wait=180):
@@ -166,7 +219,7 @@ class ComputeNodeShutdownActor(ComputeNodeStateChangeBase):
         # eligible.  Normal shutdowns based on job demand should be
         # cancellable; shutdowns based on node misbehavior should not.
         super(ComputeNodeShutdownActor, self).__init__(
-            'arvnodeman.nodedown', cloud_client, arvados_client, timer_actor,
+            cloud_client, arvados_client, timer_actor,
             retry_wait, max_retry_wait)
         self._monitor = node_monitor.proxy()
         self.cloud_node = self._monitor.cloud_node.get()
@@ -174,7 +227,11 @@ class ComputeNodeShutdownActor(ComputeNodeStateChangeBase):
         self.cancel_reason = None
         self.success = None
 
+    def _set_logger(self):
+        self._logger = logging.getLogger("%s.%s.%s" % (self.__class__.__name__, self.actor_urn[33:], self.cloud_node.name))
+
     def on_start(self):
+        super(ComputeNodeShutdownActor, self).on_start()
         self._later.shutdown_node()
 
     def _arvados_node(self):
@@ -185,49 +242,66 @@ class ComputeNodeShutdownActor(ComputeNodeStateChangeBase):
             self.success = success_flag
         return super(ComputeNodeShutdownActor, self)._finished()
 
-    def cancel_shutdown(self, reason):
+    def cancel_shutdown(self, reason, **kwargs):
+        if not self.cancellable:
+            return False
+        if self.cancel_reason is not None:
+            # already cancelled
+            return False
         self.cancel_reason = reason
-        self._logger.info("Cloud node %s shutdown cancelled: %s.",
-                          self.cloud_node.id, reason)
+        self._logger.info("Shutdown cancelled: %s.", reason)
         self._finished(success_flag=False)
+        return True
 
-    def _stop_if_window_closed(orig_func):
+    def _cancel_on_exception(orig_func):
         @functools.wraps(orig_func)
-        def stop_wrapper(self, *args, **kwargs):
-            if (self.cancellable and
-                  (not self._monitor.shutdown_eligible().get())):
-                self._later.cancel_shutdown(self.WINDOW_CLOSED)
-                return None
-            else:
+        def finish_wrapper(self, *args, **kwargs):
+            try:
                 return orig_func(self, *args, **kwargs)
-        return stop_wrapper
+            except Exception as error:
+                self._logger.error("Actor error %s", error)
+                self._logger.debug("", exc_info=True)
+                self._later.cancel_shutdown("Unhandled exception %s" % error, try_resume=False)
+        return finish_wrapper
 
-    @_stop_if_window_closed
-    @ComputeNodeStateChangeBase._retry()
+    @_cancel_on_exception
     def shutdown_node(self):
-        if not self._cloud.destroy_node(self.cloud_node):
-            if self._cloud.broken(self.cloud_node):
-                self._later.cancel_shutdown(self.NODE_BROKEN)
-            else:
-                # Force a retry.
-                raise cloud_types.LibcloudError("destroy_node failed")
-        self._logger.info("Cloud node %s shut down.", self.cloud_node.id)
+        if self.cancel_reason is not None:
+            # already cancelled
+            return
+        if self.cancellable:
+            self._logger.info("Checking that node is still eligible for shutdown")
+            eligible, reason = self._monitor.shutdown_eligible().get()
+            if not eligible:
+                self.cancel_shutdown("No longer eligible for shut down because %s" % reason,
+                                     try_resume=True)
+                return
+        # If boot failed, count the event
+        if self._monitor.get_state().get() == 'unpaired':
+            status.tracker.counter_add('boot_failures')
+        self._destroy_node()
+
+    def _destroy_node(self):
+        self._logger.info("Starting shutdown")
         arv_node = self._arvados_node()
-        if arv_node is None:
-            self._finished(success_flag=True)
+        if self._cloud.destroy_node(self.cloud_node):
+            self.cancellable = False
+            self._logger.info("Shutdown success")
+            if arv_node:
+                self._later.clean_arvados_node(arv_node)
+            else:
+                self._finished(success_flag=True)
         else:
-            self._later.clean_arvados_node(arv_node)
+            self.cancel_shutdown(self.DESTROY_FAILED, try_resume=False)
 
-    @ComputeNodeStateChangeBase._retry(config.ARVADOS_ERRORS)
+    @ComputeNodeStateChangeBase._finish_on_exception
+    @RetryMixin._retry(config.ARVADOS_ERRORS)
     def clean_arvados_node(self, arvados_node):
         self._clean_arvados_node(arvados_node, "Shut down by Node Manager")
         self._finished(success_flag=True)
 
-    # Make the decorator available to subclasses.
-    _stop_if_window_closed = staticmethod(_stop_if_window_closed)
-
 
-class ComputeNodeUpdateActor(config.actor_class):
+class ComputeNodeUpdateActor(config.actor_class, RetryMixin):
     """Actor to dispatch one-off cloud management requests.
 
     This actor receives requests for small cloud updates, and
@@ -235,42 +309,24 @@ class ComputeNodeUpdateActor(config.actor_class):
     this to perform maintenance tasks on themselves.  Having a
     dedicated actor for this gives us the opportunity to control the
     flow of requests; e.g., by backing off when errors occur.
-
-    This actor is most like a "traditional" Pykka actor: there's no
-    subscribing, but instead methods return real driver results.  If
-    you're interested in those results, you should get them from the
-    Future that the proxy method returns.  Be prepared to handle exceptions
-    from the cloud driver when you do.
     """
-    def __init__(self, cloud_factory, max_retry_wait=180):
+    def __init__(self, cloud_factory, timer_actor, max_retry_wait=180):
         super(ComputeNodeUpdateActor, self).__init__()
+        RetryMixin.__init__(self, 1, max_retry_wait,
+                            None, cloud_factory(), timer_actor)
         self._cloud = cloud_factory()
-        self.max_retry_wait = max_retry_wait
-        self.error_streak = 0
-        self.next_request_time = time.time()
+        self._later = self.actor_ref.tell_proxy()
 
-    def _throttle_errors(orig_func):
-        @functools.wraps(orig_func)
-        def throttle_wrapper(self, *args, **kwargs):
-            throttle_time = self.next_request_time - time.time()
-            if throttle_time > 0:
-                time.sleep(throttle_time)
-            self.next_request_time = time.time()
-            try:
-                result = orig_func(self, *args, **kwargs)
-            except Exception as error:
-                self.error_streak += 1
-                self.next_request_time += min(2 ** self.error_streak,
-                                              self.max_retry_wait)
-                raise
-            else:
-                self.error_streak = 0
-                return result
-        return throttle_wrapper
+    def _set_logger(self):
+        self._logger = logging.getLogger("%s.%s" % (self.__class__.__name__, self.actor_urn[33:]))
+
+    def on_start(self):
+        self._set_logger()
 
-    @_throttle_errors
+    @RetryMixin._retry()
     def sync_node(self, cloud_node, arvados_node):
-        return self._cloud.sync_node(cloud_node, arvados_node)
+        if self._cloud.node_fqdn(cloud_node) != arvados_node_fqdn(arvados_node):
+            return self._cloud.sync_node(cloud_node, arvados_node)
 
 
 class ComputeNodeMonitorActor(config.actor_class):
@@ -281,16 +337,13 @@ class ComputeNodeMonitorActor(config.actor_class):
     for shutdown.
     """
     def __init__(self, cloud_node, cloud_node_start_time, shutdown_timer,
-                 cloud_fqdn_func, timer_actor, update_actor, cloud_client,
+                 timer_actor, update_actor, cloud_client,
                  arvados_node=None, poll_stale_after=600, node_stale_after=3600,
                  boot_fail_after=1800
     ):
         super(ComputeNodeMonitorActor, self).__init__()
-        self._later = self.actor_ref.proxy()
-        self._logger = logging.getLogger('arvnodeman.computenode')
-        self._last_log = None
+        self._later = self.actor_ref.tell_proxy()
         self._shutdowns = shutdown_timer
-        self._cloud_node_fqdn = cloud_fqdn_func
         self._timer = timer_actor
         self._update = update_actor
         self._cloud = cloud_client
@@ -301,73 +354,149 @@ class ComputeNodeMonitorActor(config.actor_class):
         self.boot_fail_after = boot_fail_after
         self.subscribers = set()
         self.arvados_node = None
+        self.consecutive_idle = 0
         self._later.update_arvados_node(arvados_node)
         self.last_shutdown_opening = None
         self._later.consider_shutdown()
 
+    def _set_logger(self):
+        self._logger = logging.getLogger("%s.%s.%s" % (self.__class__.__name__, self.actor_urn[33:], self.cloud_node.name))
+
+    def on_start(self):
+        self._set_logger()
+        self._timer.schedule(self.cloud_node_start_time + self.boot_fail_after, self._later.consider_shutdown)
+
     def subscribe(self, subscriber):
         self.subscribers.add(subscriber)
 
     def _debug(self, msg, *args):
-        if msg == self._last_log:
-            return
-        self._last_log = msg
         self._logger.debug(msg, *args)
 
-    def in_state(self, *states):
-        # Return a boolean to say whether or not our Arvados node record is in
-        # one of the given states.  If state information is not
-        # available--because this node has no Arvados record, the record is
-        # stale, or the record has no state information--return None.
-        if (self.arvados_node is None) or not timestamp_fresh(
-              arvados_node_mtime(self.arvados_node), self.node_stale_after):
-            return None
+    def get_state(self):
+        """Get node state, one of ['unpaired', 'busy', 'idle', 'down']."""
+
+        # If this node is not associated with an Arvados node, return
+        # 'unpaired' if we're in the boot grace period, and 'down' if not,
+        # so it isn't counted towards usable nodes.
+        if self.arvados_node is None:
+            if timestamp_fresh(self.cloud_node_start_time,
+                               self.boot_fail_after):
+                return 'unpaired'
+            else:
+                return 'down'
+
         state = self.arvados_node['crunch_worker_state']
-        if not state:
-            return None
-        result = state in states
+
+        # If state information is not available because it is missing or the
+        # record is stale, return 'down'.
+        if not state or not timestamp_fresh(arvados_node_mtime(self.arvados_node),
+                                            self.node_stale_after):
+            state = 'down'
+
+        # There's a window between when a node pings for the first time and the
+        # value of 'slurm_state' is synchronized by crunch-dispatch.  In this
+        # window, the node will still report as 'down'.  Check that
+        # first_ping_at is truthy and consider the node 'idle' during the
+        # initial boot grace period.
+        if (state == 'down' and
+            self.arvados_node['first_ping_at'] and
+            timestamp_fresh(self.cloud_node_start_time,
+                            self.boot_fail_after) and
+            not self._cloud.broken(self.cloud_node)):
+            state = 'idle'
+
+        # "missing" means last_ping_at is stale, this should be
+        # considered "down"
+        if arvados_node_missing(self.arvados_node, self.node_stale_after):
+            state = 'down'
+
+        # Turns out using 'job_uuid' this way is a bad idea.  The node record
+        # is assigned the job_uuid before the job is locked (which removes it
+        # from the queue) which means the job will be double-counted as both in
+        # the wishlist and but also keeping a node busy.  This end result is
+        # excess nodes being booted.
+        #if state == 'idle' and self.arvados_node['job_uuid']:
+        #    state = 'busy'
+
+        # Update idle node times tracker
         if state == 'idle':
-            result = result and not self.arvados_node['job_uuid']
-        return result
+            status.tracker.idle_in(self.arvados_node['hostname'])
+        else:
+            status.tracker.idle_out(self.arvados_node['hostname'])
+
+        return state
+
+    def in_state(self, *states):
+        return self.get_state() in states
 
     def shutdown_eligible(self):
-        if not self._shutdowns.window_open():
-            return False
-        if self.arvados_node is None:
-            # Node is unpaired.
-            # If it hasn't pinged Arvados after boot_fail seconds, shut it down
-            return not timestamp_fresh(self.cloud_node_start_time, self.boot_fail_after)
-        missing = arvados_node_missing(self.arvados_node, self.node_stale_after)
-        if missing and self._cloud.broken(self.cloud_node):
-            # Node is paired, but Arvados says it is missing and the cloud says the node
-            # is in an error state, so shut it down.
-            return True
-        if missing is None and self._cloud.broken(self.cloud_node):
-            self._logger.warning(
-                "cloud reports broken node, but paired node %s never pinged "
-                "(bug?) -- skipped check for node_stale_after",
-                self.arvados_node['uuid'])
-        return self.in_state('idle')
+        """Determine if node is candidate for shut down.
+
+        Returns a tuple of (boolean, string) where the first value is whether
+        the node is candidate for shut down, and the second value is the
+        reason for the decision.
+        """
+
+        # Collect states and then consult state transition table whether we
+        # should shut down.  Possible states are:
+        # crunch_worker_state = ['unpaired', 'busy', 'idle', 'down']
+        # window = ["open", "closed"]
+        # boot_grace = ["boot wait", "boot exceeded"]
+        # idle_grace = ["not idle", "idle wait", "idle exceeded"]
+
+        if self.arvados_node and not timestamp_fresh(arvados_node_mtime(self.arvados_node), self.node_stale_after):
+            return (False, "node state is stale")
+
+        crunch_worker_state = self.get_state()
+
+        window = "open" if self._shutdowns.window_open() else "closed"
+
+        if timestamp_fresh(self.cloud_node_start_time, self.boot_fail_after):
+            boot_grace = "boot wait"
+        else:
+            boot_grace = "boot exceeded"
+
+        if crunch_worker_state == "idle":
+            # Must report as "idle" at least two consecutive times
+            if self.consecutive_idle < 2:
+                idle_grace = 'idle wait'
+            else:
+                idle_grace = 'idle exceeded'
+        else:
+            idle_grace = 'not idle'
+
+        node_state = (crunch_worker_state, window, boot_grace, idle_grace)
+        t = transitions[node_state]
+        if t is not None:
+            # yes, shutdown eligible
+            return (True, "node state is %s" % (node_state,))
+        else:
+            # no, return a reason
+            return (False, "node state is %s" % (node_state,))
 
     def consider_shutdown(self):
-        next_opening = self._shutdowns.next_opening()
-        if self.shutdown_eligible():
-            self._debug("Node %s suggesting shutdown.", self.cloud_node.id)
-            _notify_subscribers(self._later, self.subscribers)
-        elif self._shutdowns.window_open():
-            self._debug("Node %s shutdown window open but node busy.",
-                        self.cloud_node.id)
-        elif self.last_shutdown_opening != next_opening:
-            self._debug("Node %s shutdown window closed.  Next at %s.",
-                        self.cloud_node.id, time.ctime(next_opening))
-            self._timer.schedule(next_opening, self._later.consider_shutdown)
-            self.last_shutdown_opening = next_opening
+        try:
+            eligible, reason = self.shutdown_eligible()
+            next_opening = self._shutdowns.next_opening()
+            if eligible:
+                self._debug("Suggesting shutdown because %s", reason)
+                _notify_subscribers(self.actor_ref.proxy(), self.subscribers)
+            else:
+                self._debug("Not eligible for shut down because %s", reason)
+
+                if self.last_shutdown_opening != next_opening:
+                    self._debug("Shutdown window closed.  Next at %s.",
+                                time.strftime('%Y-%m-%d %H:%M:%S', time.localtime(next_opening)))
+                    self._timer.schedule(next_opening, self._later.consider_shutdown)
+                    self.last_shutdown_opening = next_opening
+        except Exception:
+            self._logger.exception("Unexpected exception")
 
     def offer_arvados_pair(self, arvados_node):
         first_ping_s = arvados_node.get('first_ping_at')
         if (self.arvados_node is not None) or (not first_ping_s):
             return None
-        elif ((arvados_node['ip_address'] in self.cloud_node.private_ips) and
+        elif ((arvados_node['info'].get('ec2_instance_id') == self._cloud.node_id(self.cloud_node)) and
               (arvados_timestamp(first_ping_s) >= self.cloud_node_start_time)):
             self._later.update_arvados_node(arvados_node)
             return self.cloud_node.id
@@ -380,8 +509,11 @@ class ComputeNodeMonitorActor(config.actor_class):
             self._later.consider_shutdown()
 
     def update_arvados_node(self, arvados_node):
-        # If the cloud node's FQDN doesn't match what's in the Arvados node
-        # record, make them match.
+        """Called when the latest Arvados node record is retrieved.
+
+        Calls the updater's sync_node() method.
+
+        """
         # This method is a little unusual in the way it just fires off the
         # request without checking the result or retrying errors.  That's
         # because this update happens every time we reload the Arvados node
@@ -390,7 +522,9 @@ class ComputeNodeMonitorActor(config.actor_class):
         # the logic to throttle those effective retries when there's trouble.
         if arvados_node is not None:
             self.arvados_node = arvados_node
-            if (self._cloud_node_fqdn(self.cloud_node) !=
-                  arvados_node_fqdn(self.arvados_node)):
-                self._update.sync_node(self.cloud_node, self.arvados_node)
+            self._update.sync_node(self.cloud_node, self.arvados_node)
+            if self.arvados_node['crunch_worker_state'] == "idle":
+                self.consecutive_idle += 1
+            else:
+                self.consecutive_idle = 0
             self._later.consider_shutdown()