X-Git-Url: https://git.arvados.org/arvados.git/blobdiff_plain/c0f33379c7fd062fc097ecef92808334e821cb6b..87e1614724027f6a9da3f3dfaa163bd8bea4ce62:/services/nodemanager/arvnodeman/computenode/__init__.py

diff --git a/services/nodemanager/arvnodeman/computenode/__init__.py b/services/nodemanager/arvnodeman/computenode/__init__.py
index b47866d2d4..6e46bc0f4c 100644
--- a/services/nodemanager/arvnodeman/computenode/__init__.py
+++ b/services/nodemanager/arvnodeman/computenode/__init__.py
@@ -31,7 +31,17 @@ def timestamp_fresh(timestamp, fresh_time):
     return (time.time() - timestamp) < fresh_time
 
 def arvados_node_missing(arvados_node, fresh_time):
-    return not timestamp_fresh(arvados_timestamp(arvados_node["last_ping_at"]), fresh_time)
+    """Indicate if cloud node corresponding to the arvados
+    node is "missing".
+
+    If True, this means the node has not pinged the API server within the timeout
+    period.  If False, the ping is up to date.  If the node has never pinged,
+    returns None.
+    """
+    if arvados_node["last_ping_at"] is None:
+        return None
+    else:
+        return not timestamp_fresh(arvados_timestamp(arvados_node["last_ping_at"]), fresh_time)
 
 class ShutdownTimer(object):
     """Keep track of a cloud node's shutdown windows.