Only sysctl reserverd ports when available.

Only set the keystone reserved ports when available, on some system
(like when running under containers) where this sysfs interface is not
exposed we are almost pretty sure these ports would be exclusive for our
devstack.

Change-Id: I06d7d227ae94d564c91c16119e4bbbcc6564a280
diff --git a/tools/fixup_stuff.sh b/tools/fixup_stuff.sh
index 1732ecc..b8beb01 100755
--- a/tools/fixup_stuff.sh
+++ b/tools/fixup_stuff.sh
@@ -50,17 +50,24 @@
 # exception into the Kernel for the Keystone AUTH ports.
 keystone_ports=${KEYSTONE_AUTH_PORT:-35357},${KEYSTONE_AUTH_PORT_INT:-35358}
 
-# Get any currently reserved ports, strip off leading whitespace
-reserved_ports=$(sysctl net.ipv4.ip_local_reserved_ports | awk -F'=' '{print $2;}' | sed 's/^ //')
+# only do the reserved ports when available, on some system (like containers)
+# where it's not exposed we are almost pretty sure these ports would be
+# exclusive for our devstack.
+if sysctl net.ipv4.ip_local_reserved_ports >/dev/null 2>&1; then
+    # Get any currently reserved ports, strip off leading whitespace
+    reserved_ports=$(sysctl net.ipv4.ip_local_reserved_ports | awk -F'=' '{print $2;}' | sed 's/^ //')
 
-if [[ -z "${reserved_ports}" ]]; then
-    # If there are no currently reserved ports, reserve the keystone ports
-    sudo sysctl -w net.ipv4.ip_local_reserved_ports=${keystone_ports}
+    if [[ -z "${reserved_ports}" ]]; then
+        # If there are no currently reserved ports, reserve the keystone ports
+        sudo sysctl -w net.ipv4.ip_local_reserved_ports=${keystone_ports}
+    else
+        # If there are currently reserved ports, keep those and also reserve the
+        # keystone specific ports. Duplicate reservations are merged into a single
+        # reservation (or range) automatically by the kernel.
+        sudo sysctl -w net.ipv4.ip_local_reserved_ports=${keystone_ports},${reserved_ports}
+    fi
 else
-    # If there are currently reserved ports, keep those and also reserve the
-    # keystone specific ports. Duplicate reservations are merged into a single
-    # reservation (or range) automatically by the kernel.
-    sudo sysctl -w net.ipv4.ip_local_reserved_ports=${keystone_ports},${reserved_ports}
+    echo_summary "WARNING: unable to reserve keystone ports"
 fi