8.1 KiB
8.1 KiB
Architecture
Status: the operator is built through Step 4 (reconciler) of docs/plans/2026-08-07-1747-proxy-operator.md. This document currently covers the event/reconcile flow; the components table and the Decisions section arrive with Step 10, and the diagrams below grow as the health engine, lease store, discovery API, and orphan GC land.
Event flow: cluster events → reconciler functions
Which functions run in response to which Kubernetes cluster events, as
wired in internal/controller/proxy_controller.go.
1. How cluster events reach the reconciler
KUBERNETES CLUSTER EVENTS (wiring: SetupWithManager,
───────────────────────── proxy_controller.go)
Proxy CR created / spec edited / Secret created / updated / deleted
status patched / delete requested │
│ │
watch: For(&crawlv1alpha1.Proxy{}) watch: Watches(&corev1.Secret{}, ...)
│ │
│ r.proxiesForSecret(ctx, secret)
│ │ r.List(Proxies in secret's namespace)
│ │ keeps those whose
│ │ spec.cloudInit.secretRef.name matches
│ ▼
│ [reconcile.Request per matching Proxy]
▼ │
┌─────────────────────────────────────────────────┴──┐
│ controller-runtime workqueue │◄── RequeueAfter timers
│ (dedup by namespace/name, rate-limited, │ (from prior reconciles)
│ MaxConcurrentReconciles: 3) │◄── error backoff retries
└──────────────────────────┬──────────────────────────┘
▼
ProxyReconciler.Reconcile(ctx, req)
The Secret watch makes rotating a cloud-init Secret a first-class event: it re-enqueues every Proxy referencing that Secret, which is how secret rotation triggers VM replacement even though the Proxy spec is untouched.
2. Inside Reconcile — dispatch and the single status write
Reconcile(ctx, req)
│ r.Get(ctx, req.NamespacedName, &p) ── fetch the Proxy (NotFound → done)
│ base := p.DeepCopy() ── snapshot for the diff
│ defer patchStatusIfChanged(ctx, base, &p) ──────────────────────────┐
│ │
├─ p.DeletionTimestamp set ──► reconcileDelete(ctx, &p) │
├─ p.Spec.Mode == External ──► reconcileExternal(ctx, &p) │
└─ otherwise (Managed) ──────► reconcileManaged(ctx, &p) │
▼
patchStatusIfChanged (status.go)
│ p.Status.ObservedGeneration = p.Generation
│ p.Status.Phase = computePhase(&p)
│ equality.Semantic.DeepEqual(base, p)?
└─ changed → r.Status().Patch(...) ◄── the ONLY
unchanged → no API call status write
3. reconcileManaged — the state machine
reconcileManaged(ctx, p)
│
├─ controllerutil.AddFinalizer? ──► r.Update ──► return {} (watch event re-triggers)
├─ permanent-failure latch (FindStatusCondition == PermanentError
│ at this generation) ──► return {} (silent until spec edit)
├─ r.Providers[p.Spec.Provider] missing ──► setProvisioned(PermanentError) → Failed
│
├─ resolveCloudInit(ctx, p) ──► r.Get(Secret) if secretRef (error → CloudInitError + backoff)
├─ hash := specHash(p, cloudInit) (spechash.go)
│
├─ status.providerID == "" ─────────► prov.Create(CreateRequest{Name: NameFromUID(p.UID), ...})
│ │ setSpecHash → r.Update (annotation)
│ └ stage providerID + Provisioned=False/Provisioning
│ ──► RequeueAfter: ProvisioningPoll
│
├─ annotation != hash, annotation == "" ──► adopt: setSpecHash → r.Update
│ ──► RequeueAfter: RequeueNow
├─ annotation != hash, annotation != "" ──► replaceInstance:
│ prov.Get ─ NotFound → setSpecHash, clear ID/IP
│ │ ──► RequeueNow (next pass creates)
│ └ exists → prov.Delete, Provisioned=False/Replacing
│ ──► RequeueAfter: DeletionPoll
│
└─ annotation == hash ──► prov.Get(providerID)
├─ ErrNotFound ──► clear ID/IP ──► RequeueNow (next pass creates)
├─ Provisioning ──► Provisioned=False ──► ProvisioningPoll
├─ Running ──► status.ip = inst.IP,
│ Provisioned=True/Created ──► DriftPoll
└─ Stopped/Termin. ──► prov.Delete (cattle) ──► DeletionPoll
any provider error ──► providerFailure(p, err) ── provider.Class(err):
├─ ErrQuotaExceeded ──► condition QuotaExceeded ──► RequeueAfter: QuotaRetry (nil error)
├─ ErrPermanent ──► condition PermanentError ──► phase Failed, no retry
└─ ErrTransient ──► return err ──► workqueue exponential backoff
4. reconcileDelete and reconcileExternal
reconcileDelete(ctx, p) reconcileExternal(ctx, p)
├─ no finalizer ──► return {} │ status.ip = spec.endpoint.host
├─ providerID == "" ──► RemoveFinalizer │ setProvisioned(True/ExternalEndpoint)
│ → r.Update → object actually deleted └─ return {} (no finalizer, no
├─ prov.Get → ErrNotFound ──► RemoveFinalizer provider calls ever;
│ → r.Update → object actually deleted the health engine —
└─ exists ──► prov.Delete Step 5 — drives the rest)
→ Provisioned=False/Deleting
──► RequeueAfter: DeletionPoll (poll until gone)
5. What provider calls do back in the cluster (kubernetes pod provider)
prov.Create ──► buildPod (pure) ──► client.Create(corev1.Pod) ─┐ these cause Pod events,
prov.Get ──► client.Get(Pod) → phase/IP → InstanceState │ but the operator does NOT
prov.Delete ──► client.Delete(Pod, tolerate NotFound) │ watch Pods — it observes
prov.ListByTag ─► client.List(Pods by labels, all namespaces) ─┘ them by polling prov.Get
on each RequeueAfter tick
The reconciler never watches provider-side resources (Pods now, GCP VMs
later). All instance-state observation is poll-based through the
Provider interface, so the same flow works identically for a cloud API
that has no watch mechanism at all.