Change cluster naming convention for e2e CI/PR jobs

scenarios/kubernetes_e2e.py

@@ -257,14 +257,21 @@ def start(self, args):
         check_env(env, self.command, *args)
 
 
-def cluster_name(cluster, build):
+def cluster_name(cluster):
     """Return or select a cluster name."""
     if cluster:
         return cluster
-    # Create a suffix based on the build number. Append a random string to it for
-    # avoiding potential conflicts across different jobs' runs (see issue #7592).
-    suffix = build if len(build) < 10 else hashlib.md5(build).hexdigest()[:10]
-    return 'e2e-%s-%s' % (suffix, os.urandom(3).encode('hex'))
+    # Create a suffix based on the build number and job name.
+    # This ensures no conflict across runs of different jobs (see #7592).
+    # For PR jobs, we use PR number instead of build number to ensure the
+    # name is constant across different runs of the presubmit on the PR.
+    # This helps clean potentially leaked resources from earlier run that
+    # could've got evicted midway (see #7673).
+    suffix = os.getenv('BUILD_NUMBER', 0)
+    suffix = os.getenv('PULL_NUMBER', suffix)
+    suffix = suffix if len(suffix) <= 10 else hashlib.md5(suffix).hexdigest()[:10]
+    suffix = suffix + '-' + hashlib.md5(os.getenv('JOB_NAME', '')).hexdigest()[:5]
+    return 'e2e-%s' % suffix
 
 
 # TODO(krzyzacy): Move this into kubetest
@@ -515,7 +522,7 @@ def main(args):
     if args.provider:
         runner_args.append('--provider=%s' % args.provider)
 
-    cluster = cluster_name(args.cluster, os.getenv('BUILD_NUMBER', 0))
+    cluster = cluster_name(args.cluster)
     runner_args.append('--cluster=%s' % cluster)
     runner_args.append('--gcp-network=%s' % cluster)
     runner_args.extend(args.kubetest_args)

scenarios/kubernetes_e2e_test.py

@@ -109,7 +109,8 @@ def test_name_filled(self):
         """Return the cluster name if set."""
         name = 'foo'
         build = '1984'
-        actual = kubernetes_e2e.cluster_name(name, build)
+        os.environ['BUILD_NUMBER'] = build
+        actual = kubernetes_e2e.cluster_name(name)
         self.assertTrue(actual)
         self.assertIn(name, actual)
         self.assertNotIn(build, actual)
@@ -118,15 +119,17 @@ def test_name_empty_short_build(self):
         """Return the build number if name is empty."""
         name = ''
         build = '1984'
-        actual = kubernetes_e2e.cluster_name(name, build)
+        os.environ['BUILD_NUMBER'] = build
+        actual = kubernetes_e2e.cluster_name(name)
         self.assertTrue(actual)
         self.assertIn(build, actual)
 
     def test_name_empty_long_build(self):
         """Return a short hash of a long build number if name is empty."""
         name = ''
         build = '0' * 63
-        actual = kubernetes_e2e.cluster_name(name, build)
+        os.environ['BUILD_NUMBER'] = build
+        actual = kubernetes_e2e.cluster_name(name)
         self.assertTrue(actual)
         self.assertNotIn(build, actual)
         if len(actual) > 32:  # Some firewall names consume half the quota