Increase fs.file-max on gtw nodes

Change-Id: I0b1433cba76c18584cea269c0c6f17fdb5af4971
Related-Prod: PROD-31906
(cherry picked from commit f12f25ec83662ea26d899f27600e225d879146a8)
diff --git a/neutron/gateway/cluster.yml b/neutron/gateway/cluster.yml
index 2a4f4f4..58aaab8 100644
--- a/neutron/gateway/cluster.yml
+++ b/neutron/gateway/cluster.yml
@@ -11,6 +11,7 @@
       kernel:
         sysctl:
           fs.inotify.max_user_instances: 4096
+          fs.file-max: 400000
   neutron:
     gateway:
       dvr: ${_param:neutron_gateway_dvr}