Index: head/release/tools/ec2.conf
===================================================================
--- head/release/tools/ec2.conf
+++ head/release/tools/ec2.conf
@@ -113,6 +113,23 @@
 		-e '1,/^#server/s/^#server.*/server 169.254.169.123 iburst/' \
 		${DESTDIR}/etc/ntp.conf
 
+	# Provide a map for accessing Elastic File System mounts
+	cat > ${DESTDIR}/etc/autofs/special_efs <<'EOF'
+#!/bin/sh
+
+if [ $# -eq 0 ]; then
+        # No way to know which EFS filesystems exist and are
+        # accessible to this EC2 instance.
+        exit 0
+fi
+
+# Provide instructions on how to mount the requested filesystem.
+FS=$1
+REGION=`fetch -qo- http://169.254.169.254/latest/meta-data/placement/availability-zone | sed -e 's/[a-z]$//'`
+echo "-nfsv4,minorversion=1,oneopenown ${FS}.efs.${REGION}.amazonaws.com:/"
+EOF
+	chmod 755 ${DESTDIR}/etc/autofs/special_efs
+
 	# The first time the AMI boots, the installed "first boot" scripts
 	# should be allowed to run:
 	# * ec2_configinit (download and process EC2 user-data)