Configure MetalLB BGP service network

apps/metallb/Chart.yaml

@@ -1,7 +1,7 @@
 # An "umbrella" chart: it declares a dependency on the upstream MetalLB
-# chart below, AND carries two templates of its own
-# (apps/metallb/templates/) — the IPAddressPool and L2Advertisement that
-# configure it. Argo CD detects this as a Helm source because a Chart.yaml
+# chart below, AND carries three templates of its own
+# (apps/metallb/templates/) — the IPAddressPool, BGPPeer, and
+# BGPAdvertisement that configure it. Argo CD detects this as a Helm source because a Chart.yaml
 # exists at this path, resolves the dependency, and syncs the combined
 # rendered output as one Application — exactly like any other app in
 # apps/. This is the real, working example of the Helm-based app pattern

apps/metallb/templates/bgpadvertisement.yaml

@@ -0,0 +1,23 @@
+# BGPAdvertisement tells MetalLB to announce allocated Service addresses as
+# routes to the MikroTik peer defined in bgppeer.yaml. Unlike Layer 2 mode,
+# the workers do not need an interface inside 10.10.60.0/24: the router learns
+# that each allocated address is reachable through the Kubernetes nodes.
+#
+# `aggregationLength: 32` advertises only addresses that a Service actually
+# owns, as individual IPv4 host routes. Advertising the whole /24 would make
+# the router send every address in the pool toward the cluster, including
+# unallocated ones.
+#
+# Sync wave 1 defers this custom resource until the MetalLB chart's CRDs and
+# controllers from wave 0 are available.
+apiVersion: metallb.io/v1beta1
+kind: BGPAdvertisement
+metadata:
+  name: default
+  namespace: metallb-system
+  annotations:
+    argocd.argoproj.io/sync-wave: "1"
+spec:
+  ipAddressPools:
+    - default-pool
+  aggregationLength: 32

apps/metallb/templates/bgppeer.yaml

@@ -0,0 +1,27 @@
+# Establishes one external BGP session from each labelled worker to the
+# MikroTik RB5009. BGP (Border Gateway Protocol) lets the workers advertise
+# service IP routes from the dedicated 10.10.60.0/24 range even though their
+# own interfaces remain in 10.10.10.0/24.
+#
+# The node selector deliberately excludes the Raspberry Pi control planes.
+# Both workers share private ASN 64520 and peer with the router's private ASN
+# 64512. The router supports ECMP, so it can retain equal-cost routes through
+# both workers when both advertise the same Service address.
+#
+# No BGP password is used on this trusted internal network. Never add one in
+# plaintext here: this repository is public, so authentication would require
+# a separately managed Kubernetes Secret.
+apiVersion: metallb.io/v1beta2
+kind: BGPPeer
+metadata:
+  name: mikrotik
+  namespace: metallb-system
+  annotations:
+    argocd.argoproj.io/sync-wave: "1"
+spec:
+  myASN: 64520
+  peerASN: 64512
+  peerAddress: 10.10.10.1
+  nodeSelectors:
+    - matchLabels:
+        node-role.kubernetes.io/worker: worker

apps/metallb/templates/ipaddresspool.yaml

@@ -1,14 +1,10 @@
-# Tells MetalLB which IP addresses it's allowed to hand out to Services.
-# Pick a small range on your LAN that nothing else will ever assign —
-# especially your router's DHCP server. MetalLB doesn't coordinate with
-# your router or DHCP server at all; it just answers network requests for
-# whatever address a Service claims from this range. If it overlaps your
-# DHCP range, you'll eventually get two devices claiming the same IP.
+# Tells MetalLB which IP addresses it may assign to LoadBalancer Services.
+# This is a dedicated routed service range, not the nodes' 10.10.10.0/24 LAN
+# and not a DHCP pool. BGPAdvertisement announces only addresses actually in
+# use, while the MikroTik accepts those routes from the two workers.
 #
-# >> Ask Claude to help you pick this range before editing it — it needs
-#    to know your LAN's subnet and DHCP range, which it can't guess.
-#    A typical home LAN answer looks like "my router hands out
-#    192.168.1.100–192.168.1.199, so let's use 192.168.1.240–192.168.1.250."
+# The first and last few addresses remain reserved for future network use.
+# Argo CD takes .10 and the demo app takes .11; .12-.250 remain available.
 #
 # This file lives under apps/metallb/templates/ alongside MetalLB's own
 # Helm-installed resources, rather than as a separate app, because it
@@ -26,4 +22,4 @@ metadata:
     argocd.argoproj.io/sync-wave: "1"
 spec:
   addresses:
-    - 192.168.1.240-192.168.1.250 # EDIT ME — replace with your chosen range
+    - 10.10.60.10-10.10.60.250

apps/metallb/templates/l2advertisement.yaml

@@ -1,19 +0,0 @@
-# L2Advertisement is what actually makes addresses from the pool reachable:
-# it tells MetalLB to answer ARP requests for whichever address a Service
-# was given, from whichever node currently hosts that Service. This is
-# "Layer 2 mode" — the simplest of MetalLB's two modes, and the right
-# choice here since it needs no cooperation from your router (the
-# alternative, BGP mode, does — worth knowing exists if you outgrow a
-# single L2 segment, not needed for this setup).
-# Same sync-wave reasoning as ipaddresspool.yaml — deferred to wave "1" so
-# it applies after MetalLB's own chart resources are up.
-apiVersion: metallb.io/v1beta1
-kind: L2Advertisement
-metadata:
-  name: default
-  namespace: metallb-system
-  annotations:
-    argocd.argoproj.io/sync-wave: "1"
-spec:
-  ipAddressPools:
-    - default-pool