jakman85andClaude Opus 5
d1a6628a97
OPERATOR DECISION 2026-09-06: "use the VIP as intended — a virtual address to reach
the cluster and provide fault tolerant HA. Without a change it will not work in HA."
THE DEFECT. Cilium's kube-proxy replacement dialled a SINGLE NODE. Re-confirmed live
before changing anything: all three prod cilium-agent pods carried
KUBERNETES_SERVICE_HOST=192.168.2.10 — k3s-prod-1's own address — while the kube-vip
VIP 192.168.2.9 was Running on all three nodes with a held lease. Lose prod-1 and the
CNI's control-plane path is dead on an "HA" cluster. clusters/prod's own comment said
the value must be the VIP and NOT .10, then called it "Not yet decided" — I treated
that stale comment as an open question when the evidence already settled it.
SPLIT, NOT REPOINT, because k3s_api_host had two consumers with opposite needs:
k3s_api_host unchanged — the FOUNDER's IP: the cold-bootstrap join
target and a tls-san. infra/tofu/outputs.tf GENERATES this
name, so renaming would ripple into tofu and the runbooks.
k3s_apiserver_endpoint NEW = {{ kube_vip_address }} — the HA address; what Cilium
consumes. Derived, not restated, so an environment overrides
ONE line and the VIP, the SAN and the CNI endpoint move
together. Prod needed no new override.
THE SECOND HAZARD, WHICH MY BRIEF DID NOT NAME and the agent found: pointing Cilium at
the VIP breaks a COLD bootstrap for the same reason the join would — site.yml ran
node-baseline -> k3s -> cilium, so Cilium would install against an address nothing
announced yet. That is the 2026-09-01 deadlock shape. Fixed by SEQUENCE, not value:
site.yml now imports kube-vip.yml BETWEEN k3s and cilium. It cannot go earlier
(kube-vip is a k3s auto-deploy manifest, so it needs a cluster) and it works there
because the DaemonSet is hostNetwork with KUBERNETES_SERVICE_HOST=127.0.0.1 — needing
neither CNI nor kube-proxy. roles/kube_vip gained a read-only `wait_for` on the VIP so
a cold run stops THERE with a named cause instead of surfacing as unreachable agents.
Also fixed a pre-existing bug that only mattered once this play joined site.yml: the
role's read-only interface probe ran without `check_mode: false`, so under --check it
was skipped and the assert fired with a misleading "set kube_vip_interface explicitly".
VERIFIED BY ME, not just reported:
renders dev K3S_API_HOST=192.168.1.49 prod=192.168.2.9 (each environment's VIP)
cilium template consumes k3s_apiserver_endpoint, not k3s_api_host
cold join still `--server https://{{ k3s_api_host }}:6443` — the founder
order site.yml: node-baseline -> k3s -> kube-vip -> cilium -> verify -> flux
gate full CI gate PASS
Agent-side, additionally: in-memory render of cilium-values.yaml.j2 per host showing
k8sServiceHost=the VIP with the join still on the founder; k3s_tls_sans renders
['.10','.9','127.0.0.1','.11','.12'] so NO cert reissue and NO k3s restart is involved
— .9 already answers under full CA verification; and --check --diff of kube-vip.yml
against prod reported 6 ok / 0 changed, i.e. the role edits change nothing about the
kube-vip prod already runs.
ha-control-plane-as-code 92 -> 112 assertions, turning two escalations into machine
checks: the Cilium template must use the endpoint var; the endpoint must derive from
kube_vip_address and k3s_api_host must not; per environment K3S_API_HOST must equal
that environment's VIP and be none of its node IPs (the [parity] contract, now
machine-checked rather than a comment); site.yml must order k3s -> kube-vip -> cilium.
Every new assertion mutation-tested and bites. One honest negative recorded: reverting
only the BASE default is not caught, because both overlays patch the key — the check
reads effective per-environment values, so the base default is unguarded.
APPLY ORDER, and this is the operator's step — nothing was applied:
PROD FIRST, and it is the low-risk direction (prod is the broken one). Push and let
Flux reconcile platform/cilium: the value change rolls the cilium-agent DaemonSet
ONE NODE AT A TIME (maxUnavailable: 1 — the knob that bounded the 2026-09-01
incident), it will not proceed past an unready pod, existing datapath survives an
agent restart, and .9 is already live before the change lands.
DEV SEPARATELY, operator present. Same mechanics but live dev agents dial
192.168.1.50, and dev is mid-DNS-migration on dev-live. Do not fold it into that.
ANSIBLE: nothing to run for either live cluster; the Ansible half matters only for a
cold build. Remove the now-redundant standalone kube-vip.yml step from any runbook.
NEW NAMED GAP, unwritten: the L2 test cannot assert the running agents' live
KUBERNETES_SERVICE_HOST, which is the drift the L0 check cannot see. Recorded in that
test's gap list.
Refs R-PLAT-01, R-NET-01, R-ENV-02.
Co-Authored-By: Claude Opus 5 <[email protected]>
79 lines
3.7 KiB
Django/Jinja
79 lines
3.7 KiB
Django/Jinja
# Cilium Helm values — rendered by the Ansible bootstrap (T-1.3).
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# PARITY CONTRACT (docs/02): the fields marked [parity] MUST equal the
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# platform/cilium HelmRelease values, or Flux and the bootstrap fight over the CNI.
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---
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# [parity] k3s kube-proxy is disabled → Cilium replaces it (ADR-0001/0002).
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kubeProxyReplacement: true
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# [parity] = k3s_apiserver_endpoint, THE HA CONTROL-PLANE VIP (kube_vip_address) — dev
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# 192.168.1.49, prod 192.168.2.9. NOT k3s_api_host, which is the FOUNDER'S OWN node IP:
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# pointing the CNI's kube-proxy replacement at one machine on a 3-server HA cluster means
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# losing that machine stops every service/policy update reaching the datapath, silently
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# (the existing datapath keeps working from Cilium's cache, so nothing looks broken). That
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# was the live state of prod until 2026-09-06 — all three cilium-agents carried
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# KUBERNETES_SERVICE_HOST=192.168.2.10 while kube-vip held .9. See group_vars/all.yml.
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#
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# [parity] The Flux side is platform/cilium/helmrelease.yaml's k8sServiceHost:
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# "${K3S_API_HOST}", whose per-environment value comes from clusters/<env>/kustomization.yaml.
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# THAT VALUE MUST EQUAL k3s_apiserver_endpoint for the SAME environment. If it does not,
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# Flux and this bootstrap render different control-plane paths and fight over the CNI.
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#
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# THE VIP MUST BE UP BEFORE THIS ROLE RUNS. playbooks/site.yml imports kube-vip.yml between
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# k3s.yml and cilium.yml for exactly this reason, and roles/kube_vip blocks until the VIP
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# answers. Rendering this against a VIP that nothing announces yet reproduces the
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# 2026-09-01 shape: agents that cannot reach the API server on a cold cluster.
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k8sServiceHost: "{{ k3s_apiserver_endpoint }}"
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k8sServicePort: {{ k3s_api_port }}
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# Ingress via Gateway API — no Traefik (docs/09, ADR-0002).
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gatewayAPI:
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enabled: true
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# Egress-class steering (ADR-0002; VPN model ADR-0013, Phase 2/3).
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egressGateway:
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enabled: true
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# Egress Gateway REQUIRES masquerade (ipv4 + eBPF). eBPF masquerade is the correct
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# pairing with kubeProxyReplacement. [parity] must match platform/cilium HelmRelease.
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enableIPv4Masquerade: true
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bpf:
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masquerade: true
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# Flow observability / isolation audit (ADR-0002).
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hubble:
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enabled: true
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relay:
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enabled: true
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ui:
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enabled: true
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# Ingress VIP announcement on the NAT LAN. IP pool / CiliumL2AnnouncementPolicy
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# (from the reserved 10.73.0.240-.250 range) is authored by WS-NET in Phase 2.
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l2announcements:
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enabled: true
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# k3s ships its own cgroup mount; point Cilium at it instead of auto-mounting.
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cgroup:
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autoMount:
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enabled: false
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hostRoot: /run/cilium/cgroupv2
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# Roll the cilium agent DaemonSet ONE node at a time. [parity] must match the
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# platform/cilium HelmRelease. The cilium 1.20.1 chart defaults this to 2, which on a
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# 3-node cluster lets one bad render take down two of three agents simultaneously —
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# exactly the 2026-09-01 incident, where k8sServiceHost: "" made the agent's `config`
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# init container fall back to the in-cluster ClusterIP 10.43.0.1:443. Only the Cilium
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# agent can translate that ClusterIP, and the agent in question was the one being
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# replaced: `dial tcp 10.43.0.1:443: i/o timeout`, deadlocked.
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# A CNI rollout has no healthy-peer fallback — the component being upgraded is the one
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# the upgrade needs to reach the API server. This bites hardest on a COLD BOOTSTRAP
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# (this role's job), where nothing healthy exists to recover from. With maxUnavailable: 1
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# the DaemonSet will not proceed past an unready pod, bounding damage to a single node.
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# Cost: Cilium upgrades serialise and take longer; at 3 nodes that is an acceptable trade.
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updateStrategy:
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type: RollingUpdate
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rollingUpdate:
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maxUnavailable: 1
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operator:
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replicas: {{ cilium_operator_replicas }}
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