[hotfix] Autoscaler's K8 support (#10766)

Co-authored-by: Richard Liaw <rliaw@berkeley.edu>

python/ray/autoscaler/command_runner.py

@@ -220,6 +220,9 @@ class KubernetesCommandRunner(CommandRunnerInterface):
                 cmd = _with_environment_variables(cmd, environment_variables)
             cmd = _with_interactive(cmd)
             final_cmd += cmd
+            # `kubectl exec` + subprocess w/ list of args has unexpected
+            # side-effects.
+            final_cmd = " ".join(final_cmd)
             logger.info(self.log_prefix + "Running {}".format(final_cmd))
             try:
                 if with_output:

python/ray/tests/test_command_runner.py

@@ -125,10 +125,7 @@ def test_kubernetes_command_runner():
         """\'true && source ~/.bashrc && export OMP_NUM_THREADS=1 PYTHONWARNINGS=ignore && (export var1=\'"\'"\'"quote between this \\" and this"\'"\'"\';export var2=\'"\'"\'"123"\'"\'"\';echo helloo)\'"""  # noqa: E501
     ]
 
-    # Much easier to debug this loop than the function call.
-    for x, y in zip(process_runner.calls[0], expected):
-        assert x == y
-    process_runner.assert_has_call("1.2.3.4", exact=expected)
+    assert process_runner.calls[0] == " ".join(expected)
 
 
 def test_docker_command_runner():