--- # ============================================================================ # Cilium Egress Gateway steering for `egress-class=vpn` pods — ADR-0015. # Serves: R-NET-04, R-NET-05, R-NET-06, R-NET-07. # R-NET-04 added 2026-09-06: this file IS the R-NET-04 datapath — the rule that selects between the # two egress paths. Omitting it made `run.sh --status` report R-NET-04 as "TEST-ONLY / impl none" # even though the implementation is right here. # # ########################################################################## # ## LIVE (2026-08-24): wired into kustomization.yaml, reconciled by Flux ## # ## and conformance-green (egress-class + vpn-killswitch pass on dev). ## # ########################################################################## # # This policy steers vpn-class pods out the gateway node's host `tun0` interface. It REQUIRES the # Ansible-managed host OpenVPN split-tunnel service on a node labeled # `homelab.keithjackson.dev/egress-gateway=true` — deploy that role BEFORE this policy reconciles, or # vpn-class pods are SNAT'd to a non-existent interface. The tunnel is live and validated end-to-end; # if tun0 is ever down, the host nftables kill-switch fails vpn-class CLOSED (see below). ADR-0015 # chose this mechanism (node tunnel + Cilium Egress Gateway); this file IS that datapath. # # --------------------------------------------------------------------------- # PREREQUISITES CONFIRMED (2026-08-24): # * Cilium Egress Gateway is ENABLED per ADR-0002 — platform/cilium/helmrelease.yaml and # platform/cilium/values.yaml both set (all [parity] with the Ansible bootstrap render): # egressGateway.enabled: true # bpf.masquerade: true (Egress Gateway REQUIRES eBPF masquerade) # kubeProxyReplacement: true # No Cilium HelmRelease change is needed for this policy. (If any of the three were false this # would be an ESCALATION, not a silent HelmRelease edit — they are all true, so we proceed.) # # INTERFACE CONTRACT (shared verbatim with the parallel Ansible host-tunnel role — ADR-0015): # * Gateway node label ...... homelab.keithjackson.dev/egress-gateway=true (applied by Ansible) # * Host tunnel interface .... tun0 (split-tunnel OpenVPN) # * Client selection ......... homelab.keithjackson.dev/egress-class=vpn (Kyverno-enforced) # --------------------------------------------------------------------------- apiVersion: cilium.io/v2 kind: CiliumEgressGatewayPolicy metadata: name: vpn-egress-steering annotations: homelab.keithjackson.dev/requirements: R-NET-04,R-NET-05,R-NET-06,R-NET-07 homelab.keithjackson.dev/adr: ADR-0015 spec: # --- Client selection (INVARIANTS 1 & 2) -------------------------------- # ONLY pods explicitly opted into the vpn class are matched. Default/internet-class pods and node # traffic are never selected, so they stay on the local/private-WAN path (invariant 1: default is # the local path). Because ONLY these flows are steered, tun0 never becomes a default route for the # node or for any other pod (invariant 2). The selector is intentionally cluster-wide (no namespace # scope) so the class label alone is the contract — every namespace's vpn-class pods route here. selectors: - podSelector: matchLabels: homelab.keithjackson.dev/egress-class: vpn # --- What gets tunneled (INVARIANT 1: only PUBLIC internet leaves via the VPN) ------------------ # destinationCIDRs is the full internet; excludedCIDRs carves out everything that must stay LOCAL: # all RFC1918 private ranges (which also cover the Cilium cluster-pool pod CIDR 10.0.0.0/8, the k3s # service/pod ranges, and the LAN 192.168.x/10.73.x node network). So intra-cluster east-west, # pod->service, and LAN traffic are NOT SNAT'd out tun0 — only genuinely public destinations are. # Excluded flows fall through to Cilium's normal local datapath (invariant 1). destinationCIDRs: - "0.0.0.0/0" # # BULK NFS (added to the record 2026-09-12, when plex/sonarr/radarr/nextcloud gained media # mounts): the export is 192.168.2.102:/mnt/Storage/plex on prod (192.168.1.9 on dev), both # inside 192.168.0.0/16 below, so NFS is excluded from the tunnel twice over. The FIRST reason # is the one that actually matters and needs no CIDR at all: an NFS PersistentVolume is mounted # by the NODE KERNEL in the host netns, not by the pod, so `selectors.podSelector` never # matches it and no pod-scoped egress steering can touch it. Verified after arming the prod # gateway: sonarr (k3s-prod-1) and radarr (k3s-prod-3, the gateway node itself) both still list # AND write the export, and the node's own mounts are intact. No RFC1918 destination needs # adding here for the media path. excludedCIDRs: - "10.0.0.0/8" # RFC1918 + Cilium cluster-pool pod CIDR (CLUSTER_POD_CIDR) + k3s service net - "172.16.0.0/12" # RFC1918 - "192.168.0.0/16" # RFC1918 (home LAN / node network family / the bulk NFS server) # --- Where it egresses -------------------------------------------------- # The gateway node (Ansible-labeled) SNATs matched traffic out its host split-tunnel `tun0`. # # CORRECTION 2026-09-12 — this comment used to say the host nftables kill-switch "is the # authoritative fail-closed backstop that DROPS this vpn-class traffic". It is not, and cannot # be. With `bpf.masquerade: true` the SNAT and egress happen in eBPF, which bpf_redirect()s the # skb to the egress device without invoking netfilter POSTROUTING, so the host nft rules never # see this traffic. Measured with a counters-only nft table on the gateway node while a # vpn-class pod egressed: 0 packets in forward and 0 in postrouting for both the pod CIDR and # the PIA range, versus 45166 packets on that same hook for WAN traffic (so the hook is live) # and 16 for a node-originated curl out tun0 (so the matching works). # WHAT ACTUALLY FAILS CLOSED: Cilium itself. When the cached egress interface/IP cannot be used # it drops the packet — tcpdump on both the WAN and tun0 during a tunnel stop AND during a # tunnel restart caught 0 packets leaving either device. vpn fails CLOSED (verified, no leak); # internet-class and node traffic are never selected and fail OPEN (invariants 3 & 4 hold). # The host nft table is retained, with counters, for the narrower case it CAN see: # node-originated traffic sourced from a tunnel address (proven on k3s-prod-3 — the drop rule's # counter moved 0 -> 3 packets when such a packet was routed at the WAN). # # SINGLE GATEWAY ONLY — there is NO failover, and a second labelled node is NOT a standby. # `egressGateway` (singular) resolves the nodeSelector to ONE node. Verbatim from the CRD # deployed on this cluster (`ciliumegressgatewaypolicies.cilium.io`, v2, Cilium 1.20.1 — # `kubectl get crd ciliumegressgatewaypolicies.cilium.io -o json`): # # "EgressGateway is the gateway node responsible for SNATing traffic. # In case multiple nodes are a match for the given set of labels, the first node # in lexical ordering based on their name will be selected." # # So labelling a second node does not create an active/standby pair — it just hands the role to # whichever node sorts FIRST BY NAME. A labelled `k3s-prod-1` would silently take the role from a # labelled `k3s-prod-3`, moving the tunnel (and the public egress IP) with no event and no alert. # LABEL EXACTLY ONE NODE. The plural `egressGateways` field (also present in 1.20) is NOT a fix: # it SHARDS endpoints across entries by CiliumEndpoint UID, so losing one entry's node blackholes # that shard and re-shards the rest (breaking live connections), and each shard exits from a # DIFFERENT public IP. Upstream: cilium/cilium#30157, cilium/cilium#18230. # ADR-0015's "Resilience: two egress-gateway nodes + Cilium Egress Gateway HA (gateway failover)" # is therefore NOT IMPLEMENTABLE on Cilium OSS — escalated for an ADR-0016 supersede; see # platform/vpn-egress/README.md and the DECISIONS-LOG entry of 2026-09-06. # # `interface: tun0` IS RESOLVED ONCE — the gateway node has to tell Cilium when tun0 changes. # Measured on k3s-dev-3 2026-09-12: Cilium caches an (egress IP, egress ifindex) pair from the # first resolution and does NOT re-resolve on a netlink change. `systemctl restart # vpn-egress-tunnel` re-creates tun0 with a NEW ifindex; the map kept the old one and vpn-class # egress was silently blackholed (tcpdump: 0 packets out the WAN, 0 out tun0 — fail-closed, but # dead). `egress-gateway-reconciliation-trigger-interval: 1s` does not cover link events. # Upstream: "it does not automatically respond to a change in the gateway node's network # configuration... You can force a fresh selection by re-applying the Egress Gateway policy." # The Ansible role closes this: roles/vpn_egress_gateway publishes # `homelab.keithjackson.dev/egress-uplink=-` on the gateway node on every # connect (plus a 2-minute convergence timer). That node update makes Cilium re-process this # policy and re-resolve the interface — verified: cached ifindex 1986 -> 1987 within 10s. # DO NOT "fix" this by having the node write to THIS object: it is Flux-managed, and a node # writing to GitOps state is a drift fight. Check the label, not this file, when debugging: # kubectl get nodes -L homelab.keithjackson.dev/egress-gateway,homelab.keithjackson.dev/egress-uplink egressGateway: nodeSelector: matchLabels: homelab.keithjackson.dev/egress-gateway: "true" interface: tun0 # --------------------------------------------------------------------------- # DONE (2026-08-24): enabled + validated + Gluetun retired. # * Host tun0 split-tunnel is up on the egress-gateway node; host nftables kill-switch in place. # * This file is wired into platform/vpn-egress/kustomization.yaml and reconciled by Flux. # * `egress-class` (R-NET-05/07) and `vpn-killswitch` (R-NET-06) conformance tests PASS live. # * The Gluetun Deployment was retired per ADR-0015 ("Gluetun is dropped as the gateway"). # ---------------------------------------------------------------------------