diff --git a/test/runner/injector/injector.py b/test/runner/injector/injector.py
index 054eba71c4c..8fb1f1166d2 100755
--- a/test/runner/injector/injector.py
+++ b/test/runner/injector/injector.py
@@ -31,6 +31,7 @@ import sys
 import pipes
 import logging
 import getpass
+import resource
 
 logger = logging.getLogger('injector')  # pylint: disable=locally-disabled, invalid-name
 # pylint: disable=locally-disabled, invalid-name
@@ -89,6 +90,17 @@ def main():
     try:
         logger.debug('Self: %s', __file__)
 
+        # to achieve a consistent nofile ulimit, set to 16k here, this can affect performance in subprocess.Popen when
+        # being called with close_fds=True on Python (8x the time on some environments)
+        nofile_limit = 16 * 1024
+        current_limit = resource.getrlimit(resource.RLIMIT_NOFILE)
+        new_limit = (nofile_limit, nofile_limit)
+        if current_limit > new_limit:
+            logger.debug('RLIMIT_NOFILE: %s -> %s', current_limit, new_limit)
+            resource.setrlimit(resource.RLIMIT_NOFILE, (nofile_limit, nofile_limit))
+        else:
+            logger.debug('RLIMIT_NOFILE: %s', current_limit)
+
         config_path = os.path.join(os.path.dirname(os.path.abspath(__file__)), 'injector.json')
 
         try:
diff --git a/test/runner/lib/cli.py b/test/runner/lib/cli.py
index b77e1af10c6..3d23a1673f6 100644
--- a/test/runner/lib/cli.py
+++ b/test/runner/lib/cli.py
@@ -4,6 +4,7 @@ from __future__ import absolute_import, print_function
 
 import errno
 import os
+import resource
 import sys
 
 from lib.util import (
@@ -84,6 +85,17 @@ def main():
         display.info_stderr = (isinstance(config, SanityConfig) and config.lint) or (isinstance(config, IntegrationConfig) and config.list_targets)
         check_startup()
 
+        # to achieve a consistent nofile ulimit, set to 16k here, this can affect performance in subprocess.Popen when
+        # being called with close_fds=True on Python (8x the time on some environments)
+        nofile_limit = 16 * 1024
+        current_limit = resource.getrlimit(resource.RLIMIT_NOFILE)
+        new_limit = (nofile_limit, nofile_limit)
+        if current_limit > new_limit:
+            display.info('RLIMIT_NOFILE: %s -> %s' % (current_limit, new_limit), verbosity=2)
+            resource.setrlimit(resource.RLIMIT_NOFILE, (nofile_limit, nofile_limit))
+        else:
+            display.info('RLIMIT_NOFILE: %s' % (current_limit, ), verbosity=2)
+
         try:
             args.func(config)
         except Delegate as ex: