Fix image preload

Signed-off-by: Tyler Gu <[email protected]>

acto/post_process/simple_crash_test.py

@@ -5,6 +5,7 @@
 import os
 import queue
 import re
+import subprocess
 import sys
 import threading
 import time
@@ -150,6 +151,15 @@ def post_process(self, workdir: str, num_workers: int = 1):
         cluster.configure_cluster(self.config.num_nodes, self.config.kubernetes_version)
         deploy = Deploy(DeployMethod.YAML, self.config.deploy.file, self.config.deploy.init).new()
 
+        # Build an archive to be preloaded
+        images_archive = os.path.join(workdir, 'images.tar')
+        if len(self.context['preload_images']) > 0:
+            # first make sure images are present locally
+            for image in self.context['preload_images']:
+                subprocess.run(['docker', 'pull', image])
+            subprocess.run(['docker', 'image', 'save', '-o', images_archive] +
+                           list(self.context['preload_images']))
+
         ################## Operation sequence crash test ######################
         workqueue = multiprocessing.Queue()
         for trial, steps in self._trial_to_steps.items():