Exit serving container when process-based cron fails (#1560)

(cherry picked from commit 79b0e96)

Author: RobertLucian

Diff for: pkg/workloads/cortex/serve/init/script.py

@@ -15,6 +15,7 @@
 import os
 import time
 import json
+import sys
 
 from cortex.lib.type import (
     predictor_type_from_api_spec,
@@ -154,7 +155,7 @@ def main():
 
         # wait until the cron finishes its first pass
         if cron:
-            while not cron.ran_once():
+            while cron.is_alive() and not cron.ran_once():
                 time.sleep(0.25)
 
             # disable live reloading when the BatchAPI kind is used
@@ -173,6 +174,13 @@ def main():
     while cron and cron.is_alive():
         time.sleep(0.25)
 
+    # exit if cron has exited with errors
+    if cron and isinstance(cron.exitcode, int) and cron.exitcode != 0:
+        # if it was killed by a signal
+        if cron.exitcode < 0:
+            sys.exit(-cron.exitcode)
+        sys.exit(cron.exitcode)
+
 
 if __name__ == "__main__":
     main()