big update based on real wokr

rig/ctrl/addons/metallb.sh

@@ -3,6 +3,7 @@
 # The pool is derived from the kind Docker network at install time.
 # Notes: docs/notes/addons.md
 set -euo pipefail
+ADDON_DIR="$(cd "$(dirname "$0")" && pwd)"   # its manifest sits beside it
 cd "${RIG_CTRL:-$(dirname "$0")/..}"
 
 source ./lib/config.sh
@@ -61,27 +62,7 @@ $K rollout status daemonset/speaker -n metallb-system --timeout=240s
 # on a race that resolves itself in seconds.
 echo "  configuring the address pool"
 for attempt in 1 2 3 4 5 6 7 8 9 10; do
-    if $K apply -f - >/dev/null 2>&1 <<YAML
-apiVersion: metallb.io/v1beta1
-kind: IPAddressPool
-metadata:
-  name: default
-  namespace: metallb-system
-spec:
-  addresses:
-    - ${pool_start}-${pool_end}
----
-# Layer 2 mode: one node answers ARP for each address. No BGP peer needed, which
-# is what makes this work on a laptop.
-apiVersion: metallb.io/v1beta1
-kind: L2Advertisement
-metadata:
-  name: default
-  namespace: metallb-system
-spec:
-  ipAddressPools:
-    - default
-YAML
+    if render_manifest "$ADDON_DIR/metallb.yaml" | $K apply -f - >/dev/null 2>&1
     then
         echo "  pool ready: ${pool_start}-${pool_end}"
         exit 0