Add glue to get initialize-urandom installed

Here we are installing our python app, and setting up systemd.  Our
server should run after haveged and before unbound.

Change-Id: I4f9b24f217f271b64f324c922948c54c46cb1110
Signed-off-by: Paul Belanger <pabelanger@redhat.com>

nodepool/elements/initialize-urandom/element-deps

@@ -0,0 +1,2 @@
+dib-init-system
+install-static

nodepool/elements/initialize-urandom/init-scripts/systemd/initialize-urandom.service

@@ -0,0 +1,13 @@
+[Unit]
+Description=Quickly initialize the nonblocking kernel random number generator at boot.
+Before=network-pre.target
+Wants=network-pre.target
+
+[Service]
+Type=oneshot
+User=root
+ExecStart=/usr/local/bin/initialize-urandom.py
+RemainAfterExit=true
+
+[Install]
+WantedBy=multi-user.target

nodepool/elements/initialize-urandom/post-install.d/80-initialize-urandom

@@ -0,0 +1,17 @@
+#!/bin/bash
+
+if [ "${DIB_DEBUG_TRACE:-0}" -gt 0 ]; then
+    set -x
+fi
+set -eu
+set -o pipefail
+
+case "$DIB_INIT_SYSTEM" in
+    systemd)
+        systemctl enable initialize-urandom.service
+        ;;
+    *)
+        echo "Unsupported init system"
+        exit 1
+        ;;
+esac

nodepool/nodepool.yaml

@@ -793,6 +793,7 @@ diskimages:
       - openstack-repos
       - nodepool-base
       - cache-devstack
+      - initialize-urandom
       - cache-bindep
       - growroot
       - infra-package-needs