diff --git a/fdroidserver/build.py b/fdroidserver/build.py
index 740d7f2c..16901e78 100644
--- a/fdroidserver/build.py
+++ b/fdroidserver/build.py
@@ -23,6 +23,7 @@ import shutil
 import glob
 import subprocess
 import re
+import resource
 import tarfile
 import traceback
 import time
@@ -1120,6 +1121,19 @@ def main():
     if not apps:
         raise FDroidException("No apps to process.")
 
+    # make sure enough open files are allowed to process everything
+    soft, hard = resource.getrlimit(resource.RLIMIT_NOFILE)
+    if len(apps) > soft:
+        try:
+            soft = len(apps) * 2
+            if soft > hard:
+                soft = hard
+            resource.setrlimit(resource.RLIMIT_NOFILE, (soft, hard))
+            logging.debug(_('Set open file limit to {integer}')
+                          .format(integer=soft))
+        except (OSError, ValueError) as e:
+            logging.warning(_('Setting open file limit failed: ') + str(e))
+
     if options.latest:
         for app in apps.values():
             for build in reversed(app.builds):
diff --git a/jenkins-build-all b/jenkins-build-all
index 2abac58c..d41d920f 100755
--- a/jenkins-build-all
+++ b/jenkins-build-all
@@ -31,7 +31,6 @@ else
         echo "No virtualization is used."
 fi
 sudo /bin/chmod -R a+rX /var/lib/libvirt/images
-ulimit -n 2048
 echo 'maximum allowed number of open file descriptors: ' `ulimit -n`
 ls -ld /var/lib/libvirt/images
 ls -l /var/lib/libvirt/images || echo no access