Add UI editing for local DNS zones

Local zones were only editable as mounted files, so operators could not manage DNS entries from the console. Add a Local zones editor backed by a shared Kubernetes ConfigMap, validate master files before saving, scope the pod service account to that ConfigMap, and reload changed zones on every replica while flushing stale cache entries.

README.md

@@ -397,13 +397,12 @@ local traffic counted correctly — see STATUS.md for the change note.
   but there is no zone transfer, so nothing calls it.
 
 **Zone name from a path.** `localzone.Load` derives each file's origin with
-`zonefile.OriginFromPath`, which takes the base name and truncates it at the
+`zonefile.OriginFromPath`. Legacy names truncate at the first dot, so
-first dot: `zones/lan.zone` and `lan.zone` both become the origin `lan.`
+`zones/lan.zone` becomes `lan.`. The console marks fully-qualified zone names
-(the doc comment on that function says `ads.zone.`, which is wrong — see
+with `zone--`, so `zone--example.com.zone` becomes `example.com.`. An explicit
-[Known inconsistencies](#known-inconsistencies)). An explicit `$ORIGIN` inside
+`$ORIGIN` inside the file wins, because `Parse` starts from that derived origin
-the file wins, because `Parse` starts from that derived origin and the
+and the directive replaces it. Records that fall outside their own zone are
-directive replaces it. Records that fall outside their own zone are dropped
+dropped (`localzone.add` returns false).
-(`localzone.add` returns false).
 
 The practical consequence: a *relative* name is qualified with the file's base
 name, not with the zone you had in mind. In `local.example.zone` (origin
@@ -431,6 +430,15 @@ records mean and where they are matched:
 one-label and deeper wildcards, SRV, TXT). `deploy/zones/local.rpz.zone.example`
 is a policy zone.
 
+**Edit zones in the console.** Open **Local zones** to create a zone or edit its
+RFC 1035 master-file records. In Kubernetes, the editor stores each file in the
+`fancy-dns-zones` ConfigMap; both replicas watch the projected files and reload
+them automatically. The API validates every file and its record owners before
+saving. The pod's service account can read and patch only this ConfigMap. The
+ConfigMap's `data` is intentionally left out of the GitOps manifest so console
+edits persist across reconciliation. For a standalone install, manage zone
+files on disk and reload the configuration.
+
 ## Blocklists
 
 A source is compiled into rules, and every source is merged into one immutable
@@ -662,11 +670,12 @@ Things to know before you apply it:
 * **No zone transfer.** AXFR/IXFR are not implemented: the master-file parser
   knows the record types, but nothing serves or accepts a transfer, and
   `zonefile.SerialNext` is unused.
-* **No dynamic update.** An UPDATE message passes the engine's shape check
+* **No RFC 2136 dynamic update.** An UPDATE message passes the engine's shape check
   (`validate` tolerates `OpcodeUpdate`) and is then handled as an ordinary
-  query. There is no RFC 2136 handling, no journal and no NOTIFY. A local zone
+  query. There is no wire-protocol update handling, journal or NOTIFY. Local
-  only changes when the file changes and the config is reloaded (SIGHUP,
+  zones are editable from the console's **Local zones** page. Kubernetes pods
-  `POST /api/settings/reload`, or a restart).
+  reload changed zone files automatically; standalone file edits need a config
+  reload or restart.
 * **No HTTP/3** for DoH despite `dns.doh.transport.mode` / `alt_svc`; the
   listener is h2 with an h2c fallback.
 * **No certificate automation**: certificates are files on disk, one per
@@ -774,11 +783,6 @@ Found while writing this file; each is a to-do, not something fixed here.
 15. **`internal/config/config.go` (`Valkey.TLS`)** — `cluster.valkey.tls` is
     never applied; `internal/cluster/cluster.go:dial` builds a plain
     `redis.Client` with no `TLSConfig`.
-16. **`internal/zonefile/zonefile.go:525-526` — the `OriginFromPath` doc
-    comment is wrong.** It claims `"rpz/ads.zone"` and `"ads.zone"` both become
-    `"ads.zone."`; the code truncates at the first dot, so both become `"ads."`.
-    The behaviour is what `localzone.Load` and `blocklist.parseRPZFiles` rely
-    on — fix the comment.
 17. **`internal/zonefile/zonefile.go:1-8` and `:238-243` — the package comment
     advertises `$INCLUDE`, the parser rejects it** ("`$INCLUDE … is not
     supported; use blocklist.local_zones or a list source instead`"), and
@@ -790,10 +794,6 @@ Found while writing this file; each is a to-do, not something fixed here.
     Unprivileged use needs the same `sed` rewrite the CI smoke test does
     (`.github/workflows/ci.yml`, "Smoke test the real binary"), or a port you
     can bind.
-19. **`deploy/k8s/10-deployment.yaml` — the comment tells the reader to manage
-    zones "through the admin API (`/api/zones`)", which does not exist.** There
-    is no zone endpoint in `internal/api/api.go:routes`; local zones are edited
-    on disk.
 20. **`deploy/k8s/20-service.yaml` — the load-balancer comment says to leave
     the LB health check on the HTTP admin port, but the `fancy-dns-dns`
     LoadBalancer Service publishes only 53/UDP, 53/TCP and 853/TCP.** The admin

deploy/k8s/05-serviceaccount.yaml

@@ -1,7 +1,6 @@
-# A stable identity for the pods. The server never talks to the Kubernetes API
+# The UI edits the shared `fancy-dns-zones` ConfigMap. Its projected volume is
-# (blocklist replication goes through Valkey, not the API server), so the token
+# read-only; these narrowly scoped permissions let the API update only that
-# is not just unused but actively undesirable: automounting it would hand every
+# one ConfigMap so both DNS replicas receive the same records.
-# pod a credential it has no reason to hold.
 apiVersion: v1
 kind: ServiceAccount
 metadata:
@@ -9,4 +8,29 @@ metadata:
   namespace: dns
   labels:
     app.kubernetes.io/name: fancy-dns
-automountServiceAccountToken: false
+automountServiceAccountToken: true
+---
+apiVersion: rbac.authorization.k8s.io/v1
+kind: Role
+metadata:
+  name: fancy-dns-zones
+  namespace: dns
+rules:
+  - apiGroups: [""]
+    resources: ["configmaps"]
+    resourceNames: ["fancy-dns-zones"]
+    verbs: ["get", "patch"]
+---
+apiVersion: rbac.authorization.k8s.io/v1
+kind: RoleBinding
+metadata:
+  name: fancy-dns-zones
+  namespace: dns
+subjects:
+  - kind: ServiceAccount
+    name: fancy-dns
+    namespace: dns
+roleRef:
+  apiGroup: rbac.authorization.k8s.io
+  kind: Role
+  name: fancy-dns-zones

deploy/k8s/06-zones.yaml

@@ -0,0 +1,11 @@
+apiVersion: v1
+kind: ConfigMap
+metadata:
+  name: fancy-dns-zones
+  namespace: dns
+  labels:
+    app.kubernetes.io/name: fancy-dns
+    app.kubernetes.io/component: local-zones
+# Leave data unmanaged by GitOps. The Local zones page writes one
+# zone--<apex>.zone
+# key per zone through the API; server-side apply preserves those user fields.

deploy/k8s/10-deployment.yaml

@@ -27,6 +27,7 @@ spec:
       annotations:
         k8s-helper.io/git-url: "https://git.k6n.net/mats/fancy-dns"
         k8s-helper.io/git-ssh: "git@git.k6n.net:mats/fancy-dns.git"
+        dns.k6n.net/zones-api: "enabled"
         # A config change is a SIGHUP, not a restart: the server re-reads the
         # file and hot-swaps every component. This annotation is for
         # stakater/reloader-class controllers; without one, `kubectl rollout
@@ -152,15 +153,13 @@ spec:
         - name: config
           configMap:
             name: fancy-dns-config
-    # Local zones are ordinary master files; ship them in a ConfigMap or
+        # Local zones are ordinary master files. The API writes them to the
-    # edit them in the mounted volume. There is no zone API — the admin API
+        # shared ConfigMap, which projects one zone--<apex>.zone file per zone here.
-    # drives blocklists, the cache and the query log, not the zone files.
+        # The GitOps manifest creates the ConfigMap empty; the UI owns its data.
-        # the data volume. Optional because the glob in the config matches
-        # nothing cleanly.
         - name: zones
           configMap:
             name: fancy-dns-zones
-            optional: true
+            optional: false
         - name: tls
           secret:
             secretName: fancy-dns-tls

deploy/k8s/kustomization.yaml

@@ -11,6 +11,7 @@ namespace: dns
 resources:
   - 00-config.yaml
   - 05-serviceaccount.yaml
+  - 06-zones.yaml
   - 10-deployment.yaml
   - 20-service.yaml
   - 30-ingress.yaml

internal/api/api.go

@@ -71,6 +71,10 @@ type Hooks struct {
 	AddDomain func(ctx context.Context, in DomainInput) (any, error)
 	// DeleteDomain removes a rule and persists the change.
 	DeleteDomain func(ctx context.Context, name, action, list string) error
+	// LocalZones lists, saves and deletes UI-managed DNS master files.
+	LocalZones      func(ctx context.Context) ([]ZoneFile, error)
+	SaveLocalZone   func(ctx context.Context, name, content string) error
+	DeleteLocalZone func(ctx context.Context, name string) error
 	// GetACL returns the ACL groups.
 	GetACL func() any
 	// PutACL validates and persists new ACL groups.
@@ -119,6 +123,12 @@ type DomainInput struct {
 	Content string `json:"content,omitempty"`
 }
 
+// ZoneFile is a UI-managed authoritative master file.
+type ZoneFile struct {
+	Name    string `json:"name"`
+	Content string `json:"content"`
+}
+
 // LogQuery pages the query log.
 type LogQuery struct {
 	Limit       int
@@ -259,6 +269,9 @@ func (s *Server) routes(cfg *config.Config) *http.ServeMux {
 	mux.Handle("POST "+base+"domains", s.authed(s.handleDomainAdd, true))
 	mux.Handle("DELETE "+base+"domains/{name...}", s.authed(s.handleDomainDelete, true))
 	mux.Handle("GET "+base+"domains/check", s.authed(s.handleDomainCheck, false))
+	mux.Handle("GET "+base+"local-zones", s.authed(s.handleLocalZones, false))
+	mux.Handle("PUT "+base+"local-zones/{name}", s.authed(s.handleLocalZonePut, true))
+	mux.Handle("DELETE "+base+"local-zones/{name}", s.authed(s.handleLocalZoneDelete, true))
 	mux.Handle("GET "+base+"clients", s.authed(s.handleClients, false))
 	mux.Handle("PUT "+base+"clients", s.authed(s.handleClientsPut, true))
 	mux.Handle("GET "+base+"upstreams", s.authed(s.handleUpstreams, false))

internal/api/handlers.go

@@ -177,6 +177,52 @@ func (s *Server) handleDomainCheck(w http.ResponseWriter, r *http.Request) {
 	writeJSON(w, http.StatusOK, v)
 }
 
+func (s *Server) handleLocalZones(w http.ResponseWriter, r *http.Request) {
+	if s.hooks.LocalZones == nil {
+		writeError(w, http.StatusNotImplemented, "local zone editor is unavailable")
+		return
+	}
+	zones, err := s.hooks.LocalZones(r.Context())
+	if err != nil {
+		writeError(w, http.StatusInternalServerError, err.Error())
+		return
+	}
+	writeJSON(w, http.StatusOK, map[string]any{"zones": zones})
+}
+
+func (s *Server) handleLocalZonePut(w http.ResponseWriter, r *http.Request) {
+	if s.hooks.SaveLocalZone == nil {
+		writeError(w, http.StatusNotImplemented, "local zone editor is unavailable")
+		return
+	}
+	var in struct {
+		Content string `json:"content"`
+	}
+	if err := decodeJSON(r, &in); err != nil {
+		writeError(w, http.StatusBadRequest, "malformed request body")
+		return
+	}
+	name := r.PathValue("name")
+	if err := s.hooks.SaveLocalZone(r.Context(), name, in.Content); err != nil {
+		writeError(w, http.StatusBadRequest, err.Error())
+		return
+	}
+	writeJSON(w, http.StatusOK, map[string]any{"ok": true, "name": name})
+}
+
+func (s *Server) handleLocalZoneDelete(w http.ResponseWriter, r *http.Request) {
+	if s.hooks.DeleteLocalZone == nil {
+		writeError(w, http.StatusNotImplemented, "local zone editor is unavailable")
+		return
+	}
+	name := r.PathValue("name")
+	if err := s.hooks.DeleteLocalZone(r.Context(), name); err != nil {
+		writeError(w, http.StatusBadRequest, err.Error())
+		return
+	}
+	writeJSON(w, http.StatusOK, map[string]any{"ok": true, "name": name})
+}
+
 // handleDomainAdd adds an inline rule.
 func (s *Server) handleDomainAdd(w http.ResponseWriter, r *http.Request) {
 	if s.hooks.AddDomain == nil {

internal/app/app.go

@@ -25,6 +25,7 @@ import (
 	"git.k8s-git-k6n.net/mats/fancy-dns/internal/cluster"
 	"git.k8s-git-k6n.net/mats/fancy-dns/internal/config"
 	"git.k8s-git-k6n.net/mats/fancy-dns/internal/engine"
+	"git.k8s-git-k6n.net/mats/fancy-dns/internal/kubezones"
 	"git.k8s-git-k6n.net/mats/fancy-dns/internal/localzone"
 	"git.k8s-git-k6n.net/mats/fancy-dns/internal/metrics"
 	"git.k8s-git-k6n.net/mats/fancy-dns/internal/qlog"
@@ -61,6 +62,7 @@ type App struct {
 	logger  *qlog.Logger
 	aclH    *acl.Holder
 	local   *localzone.Holder
+	zones   *kubezones.Client
 	pool    *resolver.Pool
 	reverse *engine.ReverseCache
 	engine  *engine.Engine
@@ -75,6 +77,8 @@ type App struct {
 	// reloadMu serialises reload work, since SIGHUP, the API and the cluster
 	// can all trigger one at the same time.
 	reloadMu sync.Mutex
+	// zoneReloadMu serialises file-watcher and config-swap recompiles.
+	zoneReloadMu sync.Mutex
 
 	startedAt time.Time
 	// degraded is set when a background component failed; surfaced in health.
@@ -96,7 +100,11 @@ func New(opt Options) (*App, error) {
 		return nil, err
 	}
 	store := config.NewStore(cfg, opt.ConfigPath)
-	return &App{opt: opt, log: log, cfg: store, ver: opt.Version}, nil
+	zones, err := kubezones.InCluster()
+	if err != nil {
+		return nil, err
+	}
+	return &App{opt: opt, log: log, cfg: store, ver: opt.Version, zones: zones}, nil
 }
 
 // newLogger builds the structured logger from config plus CLI overrides.
@@ -322,6 +330,8 @@ func (a *App) startLocalZones(cfg *config.Config) {
 // reloadLocalZones recompiles the local zone store. A failure keeps the
 // previous store: serving stale local data beats serving nothing.
 func (a *App) reloadLocalZones() {
+	a.zoneReloadMu.Lock()
+	defer a.zoneReloadMu.Unlock()
 	cfg := a.cfg.Get()
 	if len(cfg.Block.LocalZones) == 0 {
 		a.local.Set(nil)
@@ -550,6 +560,7 @@ func (a *App) startCluster(ctx context.Context, cfg *config.Config) {
 // startBackground runs the periodic jobs: cache snapshots, upstream health
 // probes and the metrics gauge.
 func (a *App) startBackground(ctx context.Context, cfg *config.Config) {
+	go a.watchLocalZones(ctx)
 	// Cache snapshots.
 	if a.cstore != nil {
 		interval := cfg.Cache.Persist.Interval.D()

internal/app/hooks.go

@@ -16,6 +16,7 @@ import (
 	"git.k8s-git-k6n.net/mats/fancy-dns/internal/metrics"
 	"git.k8s-git-k6n.net/mats/fancy-dns/internal/qlog"
 	"git.k8s-git-k6n.net/mats/fancy-dns/internal/resolver"
+	"git.k8s-git-k6n.net/mats/fancy-dns/internal/zonefile"
 )
 
 // hooks builds the api.Hooks that connect the admin API to the live
@@ -37,6 +38,9 @@ func (a *App) hooks() api.Hooks {
 		ListDomains:       a.listDomains,
 		AddDomain:         a.addDomain,
 		DeleteDomain:      a.deleteDomain,
+		LocalZones:        a.listLocalZones,
+		SaveLocalZone:     a.saveLocalZone,
+		DeleteLocalZone:   a.deleteLocalZone,
 		GetACL:            a.getACL,
 		PutACL:            a.putACL,
 		GetUpstream:       a.getUpstreams,
@@ -52,6 +56,70 @@ func (a *App) hooks() api.Hooks {
 	}
 }
 
+func (a *App) listLocalZones(ctx context.Context) ([]api.ZoneFile, error) {
+	if a.zones == nil {
+		return nil, fmt.Errorf("local zone editor is available only in Kubernetes")
+	}
+	zones, err := a.zones.List(ctx)
+	if err != nil {
+		return nil, err
+	}
+	out := make([]api.ZoneFile, 0, len(zones))
+	for _, z := range zones {
+		out = append(out, api.ZoneFile{Name: z.Name, Content: z.Content})
+	}
+	sort.Slice(out, func(i, j int) bool { return out[i].Name < out[j].Name })
+	return out, nil
+}
+
+func (a *App) saveLocalZone(ctx context.Context, name, content string) error {
+	if a.zones == nil {
+		return fmt.Errorf("local zone editor is available only in Kubernetes")
+	}
+	apex := strings.ToLower(dns.Fqdn(strings.TrimSuffix(strings.TrimSpace(name), ".")))
+	_, valid := dns.IsDomainName(apex)
+	if !valid || apex == "." || len(apex) > 243 {
+		return fmt.Errorf("invalid zone name %q", name)
+	}
+	if strings.TrimSpace(content) == "" {
+		return fmt.Errorf("zone file cannot be empty")
+	}
+	parsed, err := zonefile.Parse(strings.NewReader(content), zonefile.Options{Origin: apex, File: name + ".zone"})
+	if err != nil {
+		return fmt.Errorf("invalid zone file: %w", err)
+	}
+	if len(parsed.Records) == 0 {
+		return fmt.Errorf("zone file must contain at least one record")
+	}
+	for _, record := range parsed.Records {
+		owner := strings.ToLower(dns.Fqdn(record.Name))
+		if owner != strings.ToLower(apex) && !strings.HasSuffix(owner, "."+strings.ToLower(apex)) {
+			return fmt.Errorf("record %q is outside zone %s", owner, apex)
+		}
+	}
+	if err := a.zones.Save(ctx, strings.TrimSuffix(apex, "."), content); err != nil {
+		return err
+	}
+	if a.cache != nil {
+		a.cache.Flush()
+	}
+	return nil
+}
+
+func (a *App) deleteLocalZone(ctx context.Context, name string) error {
+	if a.zones == nil {
+		return fmt.Errorf("local zone editor is available only in Kubernetes")
+	}
+	name = strings.TrimSuffix(strings.TrimSpace(name), ".")
+	if err := a.zones.Delete(ctx, name); err != nil {
+		return err
+	}
+	if a.cache != nil {
+		a.cache.Flush()
+	}
+	return nil
+}
+
 // health is the unauthenticated probe payload.
 func (a *App) health() any {
 	status := "ok"

internal/app/localzones_watch.go

@@ -0,0 +1,76 @@
+package app
+
+import (
+	"context"
+	"crypto/sha256"
+	"fmt"
+	"os"
+	"path/filepath"
+	"sort"
+	"time"
+)
+
+// watchLocalZones reloads projected ConfigMap files on every replica. A
+// Kubernetes ConfigMap volume swaps its ..data symlink atomically when the UI
+// edits a zone; polling the contents keeps both pods in sync without routing
+// DNS changes through a single pod.
+func (a *App) watchLocalZones(ctx context.Context) {
+	if a.zones == nil {
+		return
+	}
+	last, _ := a.localZoneFingerprint()
+	ticker := time.NewTicker(2 * time.Second)
+	defer ticker.Stop()
+	for {
+		select {
+		case <-ctx.Done():
+			return
+		case <-ticker.C:
+			next, err := a.localZoneFingerprint()
+			if err != nil {
+				a.log.Warn("local zone change check failed", "error", err)
+				continue
+			}
+			if next == last {
+				continue
+			}
+			a.reloadLocalZones()
+			if a.cache != nil {
+				a.cache.Flush()
+			}
+			last = next
+		}
+	}
+}
+
+func (a *App) localZoneFingerprint() (string, error) {
+	paths := make([]string, 0)
+	for _, configured := range a.cfg.Get().Block.LocalZones {
+		path := a.cfg.Get().AbsPath(configured)
+		if matches, err := filepath.Glob(path); err == nil && len(matches) > 0 {
+			paths = append(paths, matches...)
+			continue
+		}
+		if info, err := os.Stat(path); err == nil && info.IsDir() {
+			matches, err := filepath.Glob(filepath.Join(path, "*.zone"))
+			if err != nil {
+				return "", err
+			}
+			paths = append(paths, matches...)
+			continue
+		}
+	}
+	sort.Strings(paths)
+	h := sha256.New()
+	for _, path := range paths {
+		b, err := os.ReadFile(path)
+		if err != nil {
+			return "", fmt.Errorf("read %s: %w", path, err)
+		}
+		_, _ = h.Write([]byte(path))
+		_, _ = h.Write([]byte{0})
+		_, _ = h.Write(b)
+		_, _ = h.Write([]byte{0})
+	}
+	return fmt.Sprintf("%x", h.Sum(nil)), nil
+}

internal/kubezones/client.go

@@ -0,0 +1,236 @@
+// Package kubezones stores UI-managed zone files in a Kubernetes ConfigMap.
+// The ConfigMap volume is shared by every fancy-dns replica, so UI edits do
+// not depend on which pod receives the request.
+package kubezones
+
+import (
+	"bytes"
+	"context"
+	"crypto/tls"
+	"crypto/x509"
+	"encoding/json"
+	"errors"
+	"fmt"
+	"io"
+	"net"
+	"net/http"
+	"net/url"
+	"os"
+	"strings"
+	"time"
+)
+
+const (
+	serviceAccountDir = "/var/run/secrets/kubernetes.io/serviceaccount"
+	defaultName       = "fancy-dns-zones"
+)
+
+// Zone is a ConfigMap key and its master-file contents.
+type Zone struct {
+	Name    string `json:"name"`
+	Content string `json:"content"`
+}
+
+// Client is a narrow client for the one ConfigMap the console may edit.
+type Client struct {
+	baseURL string
+	ns      string
+	name    string
+	http    *http.Client
+}
+
+// InCluster returns nil outside Kubernetes. The projected service account
+// token must be available; RBAC limits it to the fancy-dns-zones ConfigMap.
+func InCluster() (*Client, error) {
+	host := os.Getenv("KUBERNETES_SERVICE_HOST")
+	if host == "" {
+		return nil, nil
+	}
+	port := os.Getenv("KUBERNETES_SERVICE_PORT_HTTPS")
+	if port == "" {
+		port = "443"
+	}
+	ns := strings.TrimSpace(os.Getenv("POD_NAMESPACE"))
+	if ns == "" {
+		b, err := os.ReadFile(serviceAccountDir + "/namespace")
+		if err != nil {
+			return nil, fmt.Errorf("kube zones: read service account namespace: %w", err)
+		}
+		ns = strings.TrimSpace(string(b))
+	}
+	ca, err := os.ReadFile(serviceAccountDir + "/ca.crt")
+	if err != nil {
+		return nil, fmt.Errorf("kube zones: read service account CA: %w", err)
+	}
+	pool, err := x509.SystemCertPool()
+	if err != nil || pool == nil {
+		pool = x509.NewCertPool()
+	}
+	if !pool.AppendCertsFromPEM(ca) {
+		return nil, errors.New("kube zones: invalid service account CA")
+	}
+	name := os.Getenv("FANCYDNS_ZONE_CONFIGMAP")
+	if name == "" {
+		name = defaultName
+	}
+	return &Client{
+		baseURL: "https://" + net.JoinHostPort(host, port),
+		ns:      ns,
+		name:    name,
+		http: &http.Client{
+			Timeout: 10 * time.Second,
+			Transport: &http.Transport{
+				Proxy:           nil,
+				TLSClientConfig: &tls.Config{RootCAs: pool, ServerName: "kubernetes.default.svc"},
+			},
+		},
+	}, nil
+}
+
+func (c *Client) resourceURL() string {
+	return c.baseURL + "/api/v1/namespaces/" + url.PathEscape(c.ns) + "/configmaps/" + url.PathEscape(c.name)
+}
+
+// List returns all zone files stored in the managed ConfigMap.
+func (c *Client) List(ctx context.Context) ([]Zone, error) {
+	cm, _, err := c.get(ctx)
+	if err != nil {
+		return nil, err
+	}
+	out := make([]Zone, 0, len(cm.Data))
+	for name, content := range cm.Data {
+		if strings.HasPrefix(name, "zone--") && strings.HasSuffix(name, ".zone") {
+			out = append(out, Zone{Name: strings.TrimSuffix(strings.TrimPrefix(name, "zone--"), ".zone"), Content: content})
+		}
+	}
+	return out, nil
+}
+
+// Save updates or adds one zone file. Kubernetes resourceVersion makes the
+// update conditional and retrying resource-version conflicts. Separate zone
+// edits merge safely; when two editors change the same zone, the last save
+// wins.
+func (c *Client) Save(ctx context.Context, name, content string) error {
+	return c.change(ctx, filename(name), &content)
+}
+
+// Delete removes one zone file.
+func (c *Client) Delete(ctx context.Context, name string) error {
+	return c.change(ctx, filename(name), nil)
+}
+
+func filename(name string) string { return "zone--" + strings.TrimSuffix(name, ".") + ".zone" }
+
+func (c *Client) change(ctx context.Context, name string, content *string) error {
+	if !validKey(name) {
+		return errors.New("zone filename must be a DNS name ending in .zone")
+	}
+	if content != nil && len(*content) > 512*1024 {
+		return errors.New("zone file exceeds 512 KiB")
+	}
+	for attempt := 0; attempt < 3; attempt++ {
+		_, rv, err := c.get(ctx)
+		if err != nil {
+			return err
+		}
+		var value any
+		if content == nil {
+			value = nil
+		} else {
+			value = *content
+		}
+		body, err := json.Marshal(map[string]any{
+			"metadata": map[string]string{"resourceVersion": rv},
+			"data":     map[string]any{name: value},
+		})
+		if err != nil {
+			return err
+		}
+		req, err := http.NewRequestWithContext(ctx, http.MethodPatch, c.resourceURL(), bytes.NewReader(body))
+		if err != nil {
+			return err
+		}
+		if err := c.authorize(req); err != nil {
+			return err
+		}
+		req.Header.Set("Content-Type", "application/merge-patch+json")
+		resp, err := c.http.Do(req)
+		if err != nil {
+			return fmt.Errorf("kube zones: update ConfigMap: %w", err)
+		}
+		_, _ = io.Copy(io.Discard, io.LimitReader(resp.Body, 4096))
+		resp.Body.Close()
+		if resp.StatusCode == http.StatusConflict {
+			continue
+		}
+		if resp.StatusCode < 200 || resp.StatusCode >= 300 {
+			return fmt.Errorf("kube zones: update ConfigMap: Kubernetes returned %s", resp.Status)
+		}
+		return nil
+	}
+	return errors.New("kube zones: concurrent edits; reload and try again")
+}
+
+type configMap struct {
+	Metadata struct {
+		ResourceVersion string `json:"resourceVersion"`
+	} `json:"metadata"`
+	Data map[string]string `json:"data"`
+}
+
+func (c *Client) get(ctx context.Context) (configMap, string, error) {
+	req, err := http.NewRequestWithContext(ctx, http.MethodGet, c.resourceURL(), nil)
+	if err != nil {
+		return configMap{}, "", err
+	}
+	if err := c.authorize(req); err != nil {
+		return configMap{}, "", err
+	}
+	resp, err := c.http.Do(req)
+	if err != nil {
+		return configMap{}, "", fmt.Errorf("kube zones: read ConfigMap: %w", err)
+	}
+	defer resp.Body.Close()
+	if resp.StatusCode < 200 || resp.StatusCode >= 300 {
+		return configMap{}, "", fmt.Errorf("kube zones: read ConfigMap: Kubernetes returned %s", resp.Status)
+	}
+	var cm configMap
+	if err := json.NewDecoder(io.LimitReader(resp.Body, 2*1024*1024)).Decode(&cm); err != nil {
+		return configMap{}, "", fmt.Errorf("kube zones: decode ConfigMap: %w", err)
+	}
+	if cm.Data == nil {
+		cm.Data = map[string]string{}
+	}
+	return cm, cm.Metadata.ResourceVersion, nil
+}
+
+func (c *Client) authorize(req *http.Request) error {
+	token, err := os.ReadFile(serviceAccountDir + "/token")
+	if err != nil {
+		return fmt.Errorf("kube zones: read service account token: %w", err)
+	}
+	req.Header.Set("Authorization", "Bearer "+strings.TrimSpace(string(token)))
+	return nil
+}
+
+func validKey(name string) bool {
+	if !strings.HasPrefix(name, "zone--") || !strings.HasSuffix(name, ".zone") ||
+		strings.ContainsAny(name, `/\\`) || len(name) > 253 {
+		return false
+	}
+	name = strings.TrimSuffix(strings.TrimPrefix(name, "zone--"), ".zone")
+	if name == "" || strings.HasPrefix(name, ".") || strings.HasSuffix(name, ".") {
+		return false
+	}
+	for _, label := range strings.Split(name, ".") {
+		if len(label) == 0 || len(label) > 63 || label[0] == '-' || label[len(label)-1] == '-' {
+			return false
+		}
+		for _, r := range label {
+			if !(r >= 'a' && r <= 'z' || r >= '0' && r <= '9' || r == '-') {
+				return false
+			}
+		}
+	}
+	return true
+}

internal/web/dist/index.html

@@ -5,8 +5,8 @@
     <link rel="icon" type="image/svg+xml" href="/favicon.svg" />
     <meta name="viewport" content="width=device-width, initial-scale=1.0" />
     <title>web</title>
-    <script type="module" crossorigin src="/assets/index-D_F84V7q.js"></script>
+    <script type="module" crossorigin src="/assets/index-B-5PHdii.js"></script>
-    <link rel="stylesheet" crossorigin href="/assets/index-CZ8p4VMZ.css">
+    <link rel="stylesheet" crossorigin href="/assets/index-YXlSytfO.css">
   </head>
   <body>
     <div id="root"></div>

internal/zonefile/zonefile.go

@@ -577,13 +577,20 @@ func ParseFiles(paths []string, originFor func(string) string) (*Zone, error) {
 	return z, nil
 }
 
-// OriginFromPath derives a zone origin from a file path: "rpz/ads.zone" and
+// OriginFromPath derives a zone origin from a file path. Legacy names such as
-// "ads.zone" both become "ads.zone.".
+// "rpz/ads.zone" and "ads.zone" become "ads."; UI-managed names use the
+// "zone--" marker so "zone--example.com.zone" becomes "example.com.".
 func OriginFromPath(p string) string {
 	base := p
 	if i := strings.LastIndexByte(base, '/'); i >= 0 {
 		base = base[i+1:]
 	}
+	// The UI stores fully-qualified zone names with a marker so they do not
+	// collide with the legacy filename convention where "local.example.zone"
+	// means the "local." zone.
+	if strings.HasPrefix(base, "zone--") && strings.HasSuffix(base, ".zone") {
+		return ensureDot(strings.TrimSuffix(strings.TrimPrefix(base, "zone--"), ".zone"))
+	}
 	if i := strings.IndexByte(base, '.'); i > 0 {
 		base = base[:i]
 	}

web/src/App.tsx

@@ -19,6 +19,7 @@ import Dashboard from './pages/Dashboard.tsx'
 import Domains from './pages/Domains.tsx'
 import Login from './pages/Login.tsx'
 import Logs from './pages/Logs.tsx'
+import LocalZones from './pages/LocalZones.tsx'
 import NotFound from './pages/NotFound.tsx'
 import Settings from './pages/Settings.tsx'
 import Upstreams from './pages/Upstreams.tsx'
@@ -50,6 +51,7 @@ function AppRoutes() {
       <Route path="/" element={<Dashboard />} />
       <Route path="/blocklists" element={<Blocklists />} />
       <Route path="/domains" element={<Domains />} />
+      <Route path="/local-zones" element={<LocalZones />} />
       <Route path="/clients" element={<Clients />} />
       <Route path="/upstreams" element={<Upstreams />} />
       <Route path="/logs" element={<Logs />} />

web/src/components/layout/AppShell.tsx

@@ -4,6 +4,7 @@ import { NavLink, useLocation, useNavigate } from 'react-router-dom'
 import type { LucideIcon } from 'lucide-react'
 import {
   Database,
+  FileCode2,
   Globe,
   LayoutDashboard,
   ListChecks,
@@ -37,6 +38,7 @@ const NAV: NavItem[] = [
   { to: '/', label: 'Dashboard', icon: LayoutDashboard, end: true },
   { to: '/blocklists', label: 'Blocklists', icon: ListChecks },
   { to: '/domains', label: 'Domains', icon: Globe },
+  { to: '/local-zones', label: 'Local zones', icon: FileCode2 },
   { to: '/clients', label: 'Clients', icon: Users },
   { to: '/upstreams', label: 'Upstreams', icon: Network },
   { to: '/logs', label: 'Logs', icon: ScrollText },

web/src/lib/api.ts

@@ -21,6 +21,7 @@ import type {
   FlushCacheResponse,
   LoginInput,
   LoginResponse,
+  LocalZonesResponse,
   LogFilters,
   LogItem,
   LogsResponse,
@@ -319,6 +320,21 @@ export function getSettings(): Promise<SettingsResponse> {
   return apiFetch<SettingsResponse>('/api/settings')
 }
 
+export function getLocalZones(): Promise<LocalZonesResponse> {
+  return apiFetch<LocalZonesResponse>('/api/local-zones')
+}
+
+export function saveLocalZone(name: string, content: string): Promise<OkResponse> {
+  return apiFetch<OkResponse>(`/api/local-zones/${encodeURIComponent(name)}`, {
+    method: 'PUT',
+    body: JSON.stringify({ content }),
+  })
+}
+
+export function deleteLocalZone(name: string): Promise<OkResponse> {
+  return apiFetch<OkResponse>(`/api/local-zones/${encodeURIComponent(name)}`, { method: 'DELETE' })
+}
+
 export function putSettings(yaml: string): Promise<SaveSettingsResponse> {
   return apiFetch<SaveSettingsResponse>('/api/settings', {
     method: 'PUT',

web/src/lib/types.ts

@@ -512,6 +512,17 @@ export interface SettingsResponse {
   writable: boolean
 }
 
+// --- GET /api/local-zones -------------------------------------------------
+
+export interface ZoneFile {
+  name: string
+  content: string
+}
+
+export interface LocalZonesResponse {
+  zones: ZoneFile[]
+}
+
 export interface SaveSettingsResponse {
   ok: boolean
   version: number

web/src/pages/LocalZones.tsx

@@ -0,0 +1,168 @@
+/** Edit the authoritative zone files shared by the DNS replicas. */
+
+import { useEffect, useMemo, useState } from 'react'
+import { FileCode2, Plus, Save, Trash2 } from 'lucide-react'
+
+import { deleteLocalZone, getLocalZones, saveLocalZone } from '../lib/api'
+import { useWhoami } from '../lib/session.ts'
+import { useApi, useAsyncAction } from '../hooks/useApi'
+import { Button, Card, CardBody, Input, Textarea, useToast } from '../components/ui'
+import { LoadingBlock, PageError, PageHeader } from '../components/layout'
+
+const EXAMPLE = '$ORIGIN example.net.\n$TTL 300\n@ IN A 192.0.2.10\nwww IN CNAME @\n'
+
+function validApex(value: string): boolean {
+  const apex = value.trim().replace(/\.$/, '')
+  if (apex === '' || apex.length > 242) return false
+  return apex.split('.').every((label) =>
+    label.length > 0 && label.length <= 63 && /^[a-z0-9](?:[a-z0-9-]*[a-z0-9])?$/i.test(label),
+  )
+}
+
+export default function LocalZones() {
+  const { canWrite } = useWhoami()
+  const { toast } = useToast()
+  const { data, error, loading, refetch } = useApi(() => getLocalZones(), [])
+  const [selected, setSelected] = useState<string | null>(null)
+  const [draft, setDraft] = useState<{ name: string; content: string } | null>(null)
+  const [creating, setCreating] = useState(false)
+  const [newName, setNewName] = useState('')
+  const save = useAsyncAction(async (input: { name: string; content: string }) =>
+    saveLocalZone(input.name, input.content),
+  )
+  const remove = useAsyncAction(async (name: string) => deleteLocalZone(name))
+
+  const zones = data?.zones ?? []
+  const active = useMemo(() => zones.find((zone) => zone.name === selected) ?? null, [zones, selected])
+
+  useEffect(() => {
+    if (selected === null && zones.length > 0 && !creating && draft === null) setSelected(zones[0].name)
+  }, [creating, draft, selected, zones])
+
+  useEffect(() => {
+    if (active !== null && draft === null) setDraft({ name: active.name, content: active.content })
+    if (active === null && selected !== null && !creating) setDraft(null)
+  }, [active, creating, draft, selected])
+
+  const startNew = (): void => {
+    setSelected(null)
+    setDraft(null)
+    setNewName('')
+    setCreating(true)
+  }
+
+  const beginCreate = (): void => {
+    const name = newName.trim().replace(/\.$/, '').toLowerCase()
+    if (!validApex(name)) {
+      toast({ title: 'Enter a valid DNS zone name', tone: 'danger' })
+      return
+    }
+    if (zones.some((zone) => zone.name === name)) {
+      toast({ title: 'That zone already exists', tone: 'danger' })
+      return
+    }
+    setSelected(null)
+    setDraft({ name, content: `$ORIGIN ${name}.\n$TTL 300\n` })
+    setCreating(false)
+  }
+
+  const onSave = async (): Promise<void> => {
+    if (draft === null || !validApex(draft.name)) return
+    const result = await save.run(draft)
+    if (result === null) {
+      toast({ title: 'Could not save zone', description: save.error ?? undefined, tone: 'danger' })
+      return
+    }
+    setSelected(draft.name.trim().replace(/\.$/, '').toLowerCase())
+    setDraft(null)
+    await refetch()
+    toast({ title: 'Zone saved', description: 'The DNS pods will load the updated file.', tone: 'ok' })
+  }
+
+  const onDelete = async (): Promise<void> => {
+    if (selected === null) return
+    if (!window.confirm(`Delete the ${selected} zone and all of its records?`)) return
+    const result = await remove.run(selected)
+    if (result === null) {
+      toast({ title: 'Could not delete zone', description: remove.error ?? undefined, tone: 'danger' })
+      return
+    }
+    setSelected(null)
+    setDraft(null)
+    await refetch()
+    toast({ title: 'Zone deleted', tone: 'ok' })
+  }
+
+  if (loading) return <LoadingBlock />
+  if (error !== null) return <PageError error={error} onRetry={() => void refetch()} />
+
+  const changed = draft !== null && (active === null || draft.name !== active.name || draft.content !== active.content)
+
+  return (
+    <div className="space-y-4">
+      <PageHeader
+        title="Local zones"
+        description="Add authoritative DNS records shared across replicas. Missing names under a zone apex return NXDOMAIN; for a single-host override, use that hostname as the apex."
+        actions={<Button icon={Plus} onClick={startNew} disabled={!canWrite}>New zone</Button>}
+      />
+
+      <div className="grid gap-4 xl:grid-cols-[minmax(220px,0.7fr)_minmax(0,2fr)]">
+        <Card title="Zones" subtitle={`${zones.length} master files`} padded={false}>
+          <div className="space-y-1 p-2">
+            {zones.length === 0 && <p className="px-3 py-5 text-sm text-fg-subtle">No local zones yet.</p>}
+            {zones.map((zone) => (
+              <button
+                key={zone.name}
+                type="button"
+                onClick={() => { setCreating(false); setDraft(null); setSelected(zone.name) }}
+                className={`flex w-full items-center gap-2 rounded-lg px-3 py-2 text-left text-sm transition-colors ${selected === zone.name ? 'bg-accent-soft text-accent' : 'text-fg-muted hover:bg-surface-2 hover:text-fg'}`}
+              >
+                <FileCode2 size={15} aria-hidden="true" />
+                <span className="truncate font-mono">{zone.name}.</span>
+              </button>
+            ))}
+          </div>
+        </Card>
+
+        <Card
+          title={draft?.name ? `${draft.name}.zone` : 'Zone file'}
+          subtitle="RFC 1035 master-file syntax. The zone apex is used as the default origin."
+          padded={false}
+          actions={selected !== null && draft !== null && canWrite ? (
+            <Button variant="danger" icon={Trash2} onClick={() => void onDelete()} loading={remove.pending}>Delete zone</Button>
+          ) : undefined}
+        >
+          {creating ? (
+            <CardBody className="space-y-3">
+              <Input label="Zone apex" placeholder="example.net" value={newName} onChange={(event) => setNewName(event.currentTarget.value)} autoFocus />
+              <Button variant="primary" icon={Plus} onClick={beginCreate}>Create zone</Button>
+            </CardBody>
+          ) : draft === null ? (
+            <CardBody><p className="text-sm text-fg-subtle">Choose a zone or create one to add records.</p></CardBody>
+          ) : (
+            <div className="space-y-3 p-4">
+              <div className="flex flex-wrap items-end justify-between gap-3">
+                <div className="min-w-56 flex-1">
+                  <Input label="Zone apex" value={draft.name} disabled={active !== null} onChange={(event) => setDraft({ ...draft, name: event.currentTarget.value })} />
+                </div>
+                <Button variant="primary" icon={Save} onClick={() => void onSave()} loading={save.pending} disabled={!canWrite || !changed || !validApex(draft.name)}>Save records</Button>
+              </div>
+              <Textarea
+                monospace
+                rows={20}
+                spellCheck={false}
+                aria-label="DNS zone records"
+                value={draft.content}
+                onChange={(event) => setDraft({ ...draft, content: event.currentTarget.value })}
+                placeholder={EXAMPLE}
+                className="min-h-[420px] font-mono text-xs leading-6"
+              />
+              <p className="text-xs text-fg-subtle">Example: <code>@ IN A 192.0.2.10</code> or <code>www IN CNAME @</code>. Invalid records are rejected before saving.</p>
+              {!canWrite && <p className="text-xs text-warn">Your account is read-only.</p>}
+            </div>
+          )}
+        </Card>
+      </div>
+    </div>
+  )
+}