[MRG] Fix node affinity selector (#963)

[MRG] Fix node affinity selector

Author: betatim

binderhub/build.py

@@ -179,7 +179,7 @@ def get_affinity(self):
                         client.V1PreferredSchedulingTerm(
                             weight=100,
                             preference=client.V1NodeSelectorTerm(
-                                match_fields=[
+                                match_expressions=[
                                     client.V1NodeSelectorRequirement(
                                         key="kubernetes.io/hostname",
                                         operator="In",

binderhub/tests/test_build.py

@@ -102,7 +102,7 @@ def test_sticky_builds_affinity():
     assert affinity.pod_anti_affinity is None
 
     # One of the two nodes we have in our mock should be the preferred node
-    assert affinity.node_affinity.preferred_during_scheduling_ignored_during_execution[0].preference.match_fields[0].values[0] in ("node-a", "node-b")
+    assert affinity.node_affinity.preferred_during_scheduling_ignored_during_execution[0].preference.match_expressions[0].values[0] in ("node-a", "node-b")
 
 
 def test_git_credentials_passed_to_podspec_upon_submit():