Add worker reading extra_records_path from file (#2271)

* consolidate scheduled tasks into one goroutine Signed-off-by: Kristoffer Dalby <kristoffer@tailscale.com> * rename Tailcfg dns struct Signed-off-by: Kristoffer Dalby <kristoffer@tailscale.com> * add dns.extra_records_path option Signed-off-by: Kristoffer Dalby <kristoffer@tailscale.com> * prettier lint Signed-off-by: Kristoffer Dalby <kristoffer@tailscale.com> * go-fmt Signed-off-by: Kristoffer Dalby <kristoffer@tailscale.com> --------- Signed-off-by: Kristoffer Dalby <kristoffer@tailscale.com>
2024-12-17 21:47:32 +00:00 · 2024-12-13 07:52:40 +00:00 · 2024-12-13 07:52:40 +00:00 · 380fcdba17
commit 380fcdba17
parent 89a648c7dd
22 changed files with 388 additions and 81 deletions
--- a/.github/workflows/docs-deploy.yml
+++ b/.github/workflows/docs-deploy.yml
@ -12,8 +12,8 @@ on:
      # Stable release tags
      - v[0-9]+.[0-9]+.[0-9]+
    paths:
-      - 'docs/**'
-      - 'mkdocs.yml'
+      - "docs/**"
+      - "mkdocs.yml"
  workflow_dispatch:

 jobs:
--- a/.github/workflows/test-integration.yaml
+++ b/.github/workflows/test-integration.yaml
@ -43,6 +43,7 @@ jobs:
          - TestPolicyBrokenConfigCommand
          - TestDERPVerifyEndpoint
          - TestResolveMagicDNS
+          - TestResolveMagicDNSExtraRecordsPath
          - TestValidateResolvConf
          - TestDERPServerScenario
          - TestDERPServerWebsocketScenario
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@ -33,19 +33,19 @@ When automatic migration is enabled (`map_legacy_users: true`), Headscale will f
 - If `strip_email_domain: true` (the default): the Headscale username matches the "username" part of their email address.
 - If `strip_email_domain: false`: the Headscale username matches the _whole_ email address.

-On migration, Headscale will change the account's username to their `preferred_username`. **This could break any ACLs or policies which are configured to match by username.**
+  On migration, Headscale will change the account's username to their `preferred_username`. **This could break any ACLs or policies which are configured to match by username.**

-Like with Headscale v0.23.0 and earlier, this migration only works for users who haven't changed their email address since their last Headscale login.
+  Like with Headscale v0.23.0 and earlier, this migration only works for users who haven't changed their email address since their last Headscale login.

-A _successful_ automated migration should otherwise be transparent to users.
+  A _successful_ automated migration should otherwise be transparent to users.

-Once a Headscale account has been migrated, it will be _unavailable_ to be matched by the legacy process. An OIDC login with a matching username, but _non-matching_ `iss` and `sub` will instead get a _new_ Headscale account.
+  Once a Headscale account has been migrated, it will be _unavailable_ to be matched by the legacy process. An OIDC login with a matching username, but _non-matching_ `iss` and `sub` will instead get a _new_ Headscale account.

-Because of the way OIDC works, Headscale's automated migration process can _only_ work when a user tries to log in after the update. Mass updates would require Headscale implement a protocol like SCIM, which is **extremely** complicated and not available in all identity providers.
+  Because of the way OIDC works, Headscale's automated migration process can _only_ work when a user tries to log in after the update. Mass updates would require Headscale implement a protocol like SCIM, which is **extremely** complicated and not available in all identity providers.

-Administrators could also attempt to migrate users manually by editing the database, using their own mapping rules with known-good data sources.
+  Administrators could also attempt to migrate users manually by editing the database, using their own mapping rules with known-good data sources.

-Legacy account migration should have no effect on new installations where all users have a recorded `sub` and `iss`.
+  Legacy account migration should have no effect on new installations where all users have a recorded `sub` and `iss`.

 ##### What happens when automatic migration is disabled?

@ -95,6 +95,7 @@ This will also affect the way you [reference users in policies](https://github.c
 - Fixed missing `stable-debug` container tag [#2232](https://github.com/juanfont/headscale/pr/2232)
 - Loosened up `server_url` and `base_domain` check. It was overly strict in some cases. [#2248](https://github.com/juanfont/headscale/pull/2248)
 - CLI for managing users now accepts `--identifier` in addition to `--name`, usage of `--identifier` is recommended [#2261](https://github.com/juanfont/headscale/pull/2261)
+- Add `dns.extra_records_path` configuration option [#2262](https://github.com/juanfont/headscale/issues/2262)

 ## 0.23.0 (2024-09-18)

--- a/Dockerfile.integration
+++ b/Dockerfile.integration
@ -8,7 +8,7 @@ ENV GOPATH /go
 WORKDIR /go/src/headscale

 RUN apt-get update \
-  && apt-get install --no-install-recommends --yes less jq sqlite3 \
+  && apt-get install --no-install-recommends --yes less jq sqlite3 dnsutils \
  && rm -rf /var/lib/apt/lists/* \
  && apt-get clean
 RUN mkdir -p /var/run/headscale
--- a/5
+++ b/5
@ -44,7 +44,10 @@ fmt-prettier:
 	prettier --write '**/**.{ts,js,md,yaml,yml,sass,css,scss,html}'

 fmt-go:
-	golines --max-len=88 --base-formatter=gofumpt -w $(GO_SOURCES)
+	# TODO(kradalby): Reeval if we want to use 88 in the future.
+	# golines --max-len=88 --base-formatter=gofumpt -w $(GO_SOURCES)
+	gofumpt -l -w .
+	golangci-lint run --fix

 fmt-proto:
 	clang-format -i $(PROTO_SOURCES)
--- a/flake.nix
+++ b/flake.nix
@ -32,7 +32,7 @@

          # When updating go.mod or go.sum, a new sha will need to be calculated,
          # update this if you have a mismatch after doing a change to thos files.
-          vendorHash = "sha256-OPgL2q13Hus6o9Npcp2bFiDiBZvbi/x8YVH6dU5q5fg=";
+          vendorHash = "sha256-NyXMSIVcmPlUhE3LmEsYZQxJdz+e435r+GZC8umQKqQ=";

          subPackages = ["cmd/headscale"];

--- a/go.mod
+++ b/go.mod
@ -117,7 +117,7 @@ require (
 	github.com/docker/go-units v0.5.0 // indirect
 	github.com/dustin/go-humanize v1.0.1 // indirect
 	github.com/felixge/fgprof v0.9.5 // indirect
-	github.com/fsnotify/fsnotify v1.7.0 // indirect
+	github.com/fsnotify/fsnotify v1.8.0 // indirect
 	github.com/fxamacker/cbor/v2 v2.6.0 // indirect
 	github.com/gaissmai/bart v0.11.1 // indirect
 	github.com/glebarez/go-sqlite v1.22.0 // indirect
--- a/go.sum
+++ b/go.sum
@ -157,6 +157,8 @@ github.com/frankban/quicktest v1.14.6 h1:7Xjx+VpznH+oBnejlPUj8oUpdxnVs4f8XU8WnHk
 github.com/frankban/quicktest v1.14.6/go.mod h1:4ptaffx2x8+WTWXmUCuVU6aPUX1/Mz7zb5vbUoiM6w0=
 github.com/fsnotify/fsnotify v1.7.0 h1:8JEhPFa5W2WU7YfeZzPNqzMP6Lwt7L2715Ggo0nosvA=
 github.com/fsnotify/fsnotify v1.7.0/go.mod h1:40Bi/Hjc2AVfZrqy+aj+yEI+/bRxZnMJyTJwOpGvigM=
+github.com/fsnotify/fsnotify v1.8.0 h1:dAwr6QBTBZIkG8roQaJjGof0pp0EeF+tNV7YBP3F/8M=
+github.com/fsnotify/fsnotify v1.8.0/go.mod h1:8jBTzvmWwFyi3Pb8djgCCO5IBqzKJ/Jwo8TRcHyHii0=
 github.com/fxamacker/cbor/v2 v2.6.0 h1:sU6J2usfADwWlYDAFhZBQ6TnLFBHxgesMrQfQgk1tWA=
 github.com/fxamacker/cbor/v2 v2.6.0/go.mod h1:pxXPTn3joSm21Gbwsv0w9OSA2y1HFR9qXEeXQVeNoDQ=
 github.com/gaissmai/bart v0.11.1 h1:5Uv5XwsaFBRo4E5VBcb9TzY8B7zxFf+U7isDxqOrRfc=
--- a/hscontrol/app.go
+++ b/hscontrol/app.go
@ -27,6 +27,7 @@ import (
 	"github.com/juanfont/headscale/hscontrol/db"
 	"github.com/juanfont/headscale/hscontrol/derp"
 	derpServer "github.com/juanfont/headscale/hscontrol/derp/server"
+	"github.com/juanfont/headscale/hscontrol/dns"
 	"github.com/juanfont/headscale/hscontrol/mapper"
 	"github.com/juanfont/headscale/hscontrol/notifier"
 	"github.com/juanfont/headscale/hscontrol/policy"
@ -88,8 +89,9 @@ type Headscale struct {
 	DERPMap    *tailcfg.DERPMap
 	DERPServer *derpServer.DERPServer

-	polManOnce sync.Once
-	polMan     policy.PolicyManager
+	polManOnce     sync.Once
+	polMan         policy.PolicyManager
+	extraRecordMan *dns.ExtraRecordsMan

 	mapper       *mapper.Mapper
 	nodeNotifier *notifier.Notifier
@ -184,7 +186,7 @@ func NewHeadscale(cfg *types.Config) (*Headscale, error) {
 	}
 	app.authProvider = authProvider

-	if app.cfg.DNSConfig != nil && app.cfg.DNSConfig.Proxied { // if MagicDNS
+	if app.cfg.TailcfgDNSConfig != nil && app.cfg.TailcfgDNSConfig.Proxied { // if MagicDNS
 		// TODO(kradalby): revisit why this takes a list.

 		var magicDNSDomains []dnsname.FQDN
@ -196,11 +198,11 @@ func NewHeadscale(cfg *types.Config) (*Headscale, error) {
 		}

 		// we might have routes already from Split DNS
-		if app.cfg.DNSConfig.Routes == nil {
-			app.cfg.DNSConfig.Routes = make(map[string][]*dnstype.Resolver)
+		if app.cfg.TailcfgDNSConfig.Routes == nil {
+			app.cfg.TailcfgDNSConfig.Routes = make(map[string][]*dnstype.Resolver)
 		}
 		for _, d := range magicDNSDomains {
-			app.cfg.DNSConfig.Routes[d.WithoutTrailingDot()] = nil
+			app.cfg.TailcfgDNSConfig.Routes[d.WithoutTrailingDot()] = nil
 		}
 	}

@ -237,23 +239,38 @@ func (h *Headscale) redirect(w http.ResponseWriter, req *http.Request) {
 	http.Redirect(w, req, target, http.StatusFound)
 }

-// expireExpiredNodes expires nodes that have an explicit expiry set
-// after that expiry time has passed.
-func (h *Headscale) expireExpiredNodes(ctx context.Context, every time.Duration) {
-	ticker := time.NewTicker(every)
+func (h *Headscale) scheduledTasks(ctx context.Context) {
+	expireTicker := time.NewTicker(updateInterval)
+	defer expireTicker.Stop()

-	lastCheck := time.Unix(0, 0)
-	var update types.StateUpdate
-	var changed bool
+	lastExpiryCheck := time.Unix(0, 0)
+
+	derpTicker := time.NewTicker(h.cfg.DERP.UpdateFrequency)
+	defer derpTicker.Stop()
+	// If we dont want auto update, just stop the ticker
+	if !h.cfg.DERP.AutoUpdate {
+		derpTicker.Stop()
+	}
+
+	var extraRecordsUpdate <-chan []tailcfg.DNSRecord
+	if h.extraRecordMan != nil {
+		extraRecordsUpdate = h.extraRecordMan.UpdateCh()
+	} else {
+		extraRecordsUpdate = make(chan []tailcfg.DNSRecord)
+	}

 	for {
 		select {
 		case <-ctx.Done():
-			ticker.Stop()
+			log.Info().Caller().Msg("scheduled task worker is shutting down.")
 			return
-		case <-ticker.C:
+
+		case <-expireTicker.C:
+			var update types.StateUpdate
+			var changed bool
+
 			if err := h.db.Write(func(tx *gorm.DB) error {
-				lastCheck, update, changed = db.ExpireExpiredNodes(tx, lastCheck)
+				lastExpiryCheck, update, changed = db.ExpireExpiredNodes(tx, lastExpiryCheck)

 				return nil
 			}); err != nil {
@ -267,24 +284,8 @@ func (h *Headscale) expireExpiredNodes(ctx context.Context, every time.Duration)
 				ctx := types.NotifyCtx(context.Background(), "expire-expired", "na")
 				h.nodeNotifier.NotifyAll(ctx, update)
 			}
-		}
-	}
-}

-// scheduledDERPMapUpdateWorker refreshes the DERPMap stored on the global object
-// at a set interval.
-func (h *Headscale) scheduledDERPMapUpdateWorker(cancelChan <-chan struct{}) {
-	log.Info().
-		Dur("frequency", h.cfg.DERP.UpdateFrequency).
-		Msg("Setting up a DERPMap update worker")
-	ticker := time.NewTicker(h.cfg.DERP.UpdateFrequency)
-
-	for {
-		select {
-		case <-cancelChan:
-			return
-
-		case <-ticker.C:
+		case <-derpTicker.C:
 			log.Info().Msg("Fetching DERPMap updates")
 			h.DERPMap = derp.GetDERPMap(h.cfg.DERP)
 			if h.cfg.DERP.ServerEnabled && h.cfg.DERP.AutomaticallyAddEmbeddedDerpRegion {
@ -297,6 +298,19 @@ func (h *Headscale) scheduledDERPMapUpdateWorker(cancelChan <-chan struct{}) {
 				Type:    types.StateDERPUpdated,
 				DERPMap: h.DERPMap,
 			})
+
+		case records, ok := <-extraRecordsUpdate:
+			if !ok {
+				continue
+			}
+			h.cfg.TailcfgDNSConfig.ExtraRecords = records
+
+			ctx := types.NotifyCtx(context.Background(), "dns-extrarecord", "all")
+			h.nodeNotifier.NotifyAll(ctx, types.StateUpdate{
+				// TODO(kradalby): We can probably do better than sending a full update here,
+				// but for now this will ensure that all of the nodes get the new records.
+				Type: types.StateFullUpdate,
+			})
 		}
 	}
 }
@ -568,12 +582,6 @@ func (h *Headscale) Serve() error {
 		go h.DERPServer.ServeSTUN()
 	}

-	if h.cfg.DERP.AutoUpdate {
-		derpMapCancelChannel := make(chan struct{})
-		defer func() { derpMapCancelChannel <- struct{}{} }()
-		go h.scheduledDERPMapUpdateWorker(derpMapCancelChannel)
-	}
-
 	if len(h.DERPMap.Regions) == 0 {
 		return errEmptyInitialDERPMap
 	}
@ -591,9 +599,21 @@ func (h *Headscale) Serve() error {
 		h.ephemeralGC.Schedule(node.ID, h.cfg.EphemeralNodeInactivityTimeout)
 	}

-	expireNodeCtx, expireNodeCancel := context.WithCancel(context.Background())
-	defer expireNodeCancel()
-	go h.expireExpiredNodes(expireNodeCtx, updateInterval)
+	if h.cfg.DNSConfig.ExtraRecordsPath != "" {
+		h.extraRecordMan, err = dns.NewExtraRecordsManager(h.cfg.DNSConfig.ExtraRecordsPath)
+		if err != nil {
+			return fmt.Errorf("setting up extrarecord manager: %w", err)
+		}
+		h.cfg.TailcfgDNSConfig.ExtraRecords = h.extraRecordMan.Records()
+		go h.extraRecordMan.Run()
+		defer h.extraRecordMan.Close()
+	}
+
+	// Start all scheduled tasks, e.g. expiring nodes, derp updates and
+	// records updates
+	scheduleCtx, scheduleCancel := context.WithCancel(context.Background())
+	defer scheduleCancel()
+	go h.scheduledTasks(scheduleCtx)

 	if zl.GlobalLevel() == zl.TraceLevel {
 		zerolog.RespLog = true
@ -847,7 +867,7 @@ func (h *Headscale) Serve() error {
 					Str("signal", sig.String()).
 					Msg("Received signal to stop, shutting down gracefully")

-				expireNodeCancel()
+				scheduleCancel()
 				h.ephemeralGC.Close()

 				// Gracefully shut down servers
--- a/hscontrol/auth.go
+++ b/hscontrol/auth.go
@ -390,7 +390,6 @@ func (h *Headscale) handleAuthKey(
 			http.Error(writer, "Internal server error", http.StatusInternalServerError)
 			return
 		}
-
 	}

 	err = h.db.Write(func(tx *gorm.DB) error {
--- a/hscontrol/db/db_test.go
+++ b/hscontrol/db/db_test.go
@ -373,6 +373,5 @@ func TestConstraints(t *testing.T) {

 			tt.run(t, db.DB.Debug())
 		})
-
 	}
 }
--- a/hscontrol/dns/extrarecords.go
+++ b/hscontrol/dns/extrarecords.go
@ -0,0 +1,155 @@
+package dns
+
+import (
+	"crypto/sha256"
+	"encoding/json"
+	"fmt"
+	"os"
+	"sync"
+
+	"github.com/fsnotify/fsnotify"
+	"github.com/rs/zerolog/log"
+	"tailscale.com/tailcfg"
+	"tailscale.com/util/set"
+)
+
+type ExtraRecordsMan struct {
+	mu      sync.RWMutex
+	records set.Set[tailcfg.DNSRecord]
+	watcher *fsnotify.Watcher
+	path    string
+
+	updateCh chan []tailcfg.DNSRecord
+	closeCh  chan struct{}
+	hashes   map[string][32]byte
+}
+
+// NewExtraRecordsManager creates a new ExtraRecordsMan and starts watching the file at the given path.
+func NewExtraRecordsManager(path string) (*ExtraRecordsMan, error) {
+	watcher, err := fsnotify.NewWatcher()
+	if err != nil {
+		return nil, fmt.Errorf("creating watcher: %w", err)
+	}
+
+	fi, err := os.Stat(path)
+	if err != nil {
+		return nil, fmt.Errorf("getting file info: %w", err)
+	}
+
+	if fi.IsDir() {
+		return nil, fmt.Errorf("path is a directory, only file is supported: %s", path)
+	}
+
+	records, hash, err := readExtraRecordsFromPath(path)
+	if err != nil {
+		return nil, fmt.Errorf("reading extra records from path: %w", err)
+	}
+
+	er := &ExtraRecordsMan{
+		watcher: watcher,
+		path:    path,
+		records: set.SetOf(records),
+		hashes: map[string][32]byte{
+			path: hash,
+		},
+		closeCh:  make(chan struct{}),
+		updateCh: make(chan []tailcfg.DNSRecord),
+	}
+
+	err = watcher.Add(path)
+	if err != nil {
+		return nil, fmt.Errorf("adding path to watcher: %w", err)
+	}
+
+	log.Trace().Caller().Strs("watching", watcher.WatchList()).Msg("started filewatcher")
+
+	return er, nil
+}
+
+func (e *ExtraRecordsMan) Records() []tailcfg.DNSRecord {
+	e.mu.RLock()
+	defer e.mu.RUnlock()
+
+	return e.records.Slice()
+}
+
+func (e *ExtraRecordsMan) Run() {
+	for {
+		select {
+		case <-e.closeCh:
+			return
+		case event, ok := <-e.watcher.Events:
+			if !ok {
+				log.Error().Caller().Msgf("file watcher event channel closing")
+				return
+			}
+
+			log.Trace().Caller().Str("path", event.Name).Str("op", event.Op.String()).Msg("extra records received filewatch event")
+			if event.Name != e.path {
+				continue
+			}
+			e.updateRecords()
+
+		case err, ok := <-e.watcher.Errors:
+			if !ok {
+				log.Error().Caller().Msgf("file watcher error channel closing")
+				return
+			}
+			log.Error().Caller().Err(err).Msgf("extra records filewatcher returned error: %q", err)
+		}
+	}
+}
+
+func (e *ExtraRecordsMan) Close() {
+	e.watcher.Close()
+	close(e.closeCh)
+}
+
+func (e *ExtraRecordsMan) UpdateCh() <-chan []tailcfg.DNSRecord {
+	return e.updateCh
+}
+
+func (e *ExtraRecordsMan) updateRecords() {
+	records, newHash, err := readExtraRecordsFromPath(e.path)
+	if err != nil {
+		log.Error().Caller().Err(err).Msgf("reading extra records from path: %s", e.path)
+		return
+	}
+
+	e.mu.Lock()
+	defer e.mu.Unlock()
+
+	// If there has not been any change, ignore the update.
+	if oldHash, ok := e.hashes[e.path]; ok {
+		if newHash == oldHash {
+			return
+		}
+	}
+
+	oldCount := e.records.Len()
+
+	e.records = set.SetOf(records)
+	e.hashes[e.path] = newHash
+
+	log.Trace().Caller().Interface("records", e.records).Msgf("extra records updated from path, count old: %d, new: %d", oldCount, e.records.Len())
+	e.updateCh <- e.records.Slice()
+}
+
+// readExtraRecordsFromPath reads a JSON file of tailcfg.DNSRecord
+// and returns the records and the hash of the file.
+func readExtraRecordsFromPath(path string) ([]tailcfg.DNSRecord, [32]byte, error) {
+	b, err := os.ReadFile(path)
+	if err != nil {
+		return nil, [32]byte{}, fmt.Errorf("reading path: %s, err: %w", path, err)
+	}
+
+	var records []tailcfg.DNSRecord
+	err = json.Unmarshal(b, &records)
+	if err != nil {
+		return nil, [32]byte{}, fmt.Errorf("unmarshalling records, content: %q: %w", string(b), err)
+	}
+
+	hash := sha256.Sum256(b)
+
+	return records, hash, nil
+}
--- a/hscontrol/mapper/mapper.go
+++ b/hscontrol/mapper/mapper.go
@ -116,11 +116,11 @@ func generateDNSConfig(
 	cfg *types.Config,
 	node *types.Node,
 ) *tailcfg.DNSConfig {
-	if cfg.DNSConfig == nil {
+	if cfg.TailcfgDNSConfig == nil {
 		return nil
 	}

-	dnsConfig := cfg.DNSConfig.Clone()
+	dnsConfig := cfg.TailcfgDNSConfig.Clone()

 	addNextDNSMetadata(dnsConfig.Resolvers, node)

--- a/hscontrol/mapper/mapper_test.go
+++ b/hscontrol/mapper/mapper_test.go
@ -117,7 +117,7 @@ func TestDNSConfigMapResponse(t *testing.T) {

 			got := generateDNSConfig(
 				&types.Config{
-					DNSConfig: &dnsConfigOrig,
+					TailcfgDNSConfig: &dnsConfigOrig,
 				},
 				nodeInShared1,
 			)
@ -349,7 +349,7 @@ func Test_fullMapResponse(t *testing.T) {
 			derpMap: &tailcfg.DERPMap{},
 			cfg: &types.Config{
 				BaseDomain:          "",
-				DNSConfig:           &tailcfg.DNSConfig{},
+				TailcfgDNSConfig:    &tailcfg.DNSConfig{},
 				LogTail:             types.LogTailConfig{Enabled: false},
 				RandomizeClientPort: false,
 			},
@ -381,7 +381,7 @@ func Test_fullMapResponse(t *testing.T) {
 			derpMap: &tailcfg.DERPMap{},
 			cfg: &types.Config{
 				BaseDomain:          "",
-				DNSConfig:           &tailcfg.DNSConfig{},
+				TailcfgDNSConfig:    &tailcfg.DNSConfig{},
 				LogTail:             types.LogTailConfig{Enabled: false},
 				RandomizeClientPort: false,
 			},
@ -424,7 +424,7 @@ func Test_fullMapResponse(t *testing.T) {
 			derpMap: &tailcfg.DERPMap{},
 			cfg: &types.Config{
 				BaseDomain:          "",
-				DNSConfig:           &tailcfg.DNSConfig{},
+				TailcfgDNSConfig:    &tailcfg.DNSConfig{},
 				LogTail:             types.LogTailConfig{Enabled: false},
 				RandomizeClientPort: false,
 			},
--- a/hscontrol/mapper/tail_test.go
+++ b/hscontrol/mapper/tail_test.go
@ -187,7 +187,7 @@ func TestTailNode(t *testing.T) {
 			polMan, _ := policy.NewPolicyManagerForTest(tt.pol, []types.User{}, types.Nodes{tt.node})
 			cfg := &types.Config{
 				BaseDomain:          tt.baseDomain,
-				DNSConfig:           tt.dnsConfig,
+				TailcfgDNSConfig:    tt.dnsConfig,
 				RandomizeClientPort: false,
 			}
 			got, err := tailNode(
--- a/hscontrol/oidc.go
+++ b/hscontrol/oidc.go
@ -447,7 +447,7 @@ func (a *AuthProviderOIDC) createOrUpdateUserFromClaim(

 	// This check is for legacy, if the user cannot be found by the OIDC identifier
 	// look it up by username. This should only be needed once.
-	// This branch will presist for a number of versions after the OIDC migration and
+	// This branch will persist for a number of versions after the OIDC migration and
 	// then be removed following a deprecation.
 	// TODO(kradalby): Remove when strip_email_domain and migration is removed
 	// after #2170 is cleaned up.
@ -536,7 +536,7 @@ func renderOIDCCallbackTemplate(

 // TODO(kradalby): Reintroduce when strip_email_domain is removed
 // after #2170 is cleaned up
-// DEPRECATED: DO NOT USE
+// DEPRECATED: DO NOT USE.
 func getUserName(
 	claims *types.OIDCClaims,
 	stripEmaildomain bool,
--- a/hscontrol/types/config.go
+++ b/hscontrol/types/config.go
@ -72,7 +72,14 @@ type Config struct {
 	ACMEURL   string
 	ACMEEmail string

-	DNSConfig *tailcfg.DNSConfig
+	// DNSConfig is the headscale representation of the DNS configuration.
+	// It is kept in the config update for some settings that are
+	// not directly converted into a tailcfg.DNSConfig.
+	DNSConfig DNSConfig
+
+	// TailcfgDNSConfig is the tailcfg representation of the DNS configuration,
+	// it can be used directly when sending Netmaps to clients.
+	TailcfgDNSConfig *tailcfg.DNSConfig

 	UnixSocket           string
 	UnixSocketPermission fs.FileMode
@ -90,11 +97,12 @@ type Config struct {
 }

 type DNSConfig struct {
-	MagicDNS      bool   `mapstructure:"magic_dns"`
-	BaseDomain    string `mapstructure:"base_domain"`
-	Nameservers   Nameservers
-	SearchDomains []string            `mapstructure:"search_domains"`
-	ExtraRecords  []tailcfg.DNSRecord `mapstructure:"extra_records"`
+	MagicDNS         bool   `mapstructure:"magic_dns"`
+	BaseDomain       string `mapstructure:"base_domain"`
+	Nameservers      Nameservers
+	SearchDomains    []string            `mapstructure:"search_domains"`
+	ExtraRecords     []tailcfg.DNSRecord `mapstructure:"extra_records"`
+	ExtraRecordsPath string              `mapstructure:"extra_records_path"`
 }

 type Nameservers struct {
@ -253,7 +261,6 @@ func LoadConfig(path string, isFile bool) error {
 	viper.SetDefault("dns.nameservers.global", []string{})
 	viper.SetDefault("dns.nameservers.split", map[string]string{})
 	viper.SetDefault("dns.search_domains", []string{})
-	viper.SetDefault("dns.extra_records", []tailcfg.DNSRecord{})

 	viper.SetDefault("derp.server.enabled", false)
 	viper.SetDefault("derp.server.stun.enabled", true)
@ -344,6 +351,10 @@ func validateServerConfig() error {
 		}
 	}

+	if viper.IsSet("dns.extra_records") && viper.IsSet("dns.extra_records_path") {
+		log.Fatal().Msg("Fatal config error: dns.extra_records and dns.extra_records_path are mutually exclusive. Please remove one of them from your config file")
+	}
+
 	// Collect any validation errors and return them all at once
 	var errorText string
 	if (viper.GetString("tls_letsencrypt_hostname") != "") &&
@ -586,6 +597,7 @@ func dns() (DNSConfig, error) {
 	dns.Nameservers.Global = viper.GetStringSlice("dns.nameservers.global")
 	dns.Nameservers.Split = viper.GetStringMapStringSlice("dns.nameservers.split")
 	dns.SearchDomains = viper.GetStringSlice("dns.search_domains")
+	dns.ExtraRecordsPath = viper.GetString("dns.extra_records_path")

 	if viper.IsSet("dns.extra_records") {
 		var extraRecords []tailcfg.DNSRecord
@ -871,7 +883,8 @@ func LoadServerConfig() (*Config, error) {

 		TLS: tlsConfig(),

-		DNSConfig: dnsToTailcfgDNS(dnsConfig),
+		DNSConfig:        dnsConfig,
+		TailcfgDNSConfig: dnsToTailcfgDNS(dnsConfig),

 		ACMEEmail: viper.GetString("acme_email"),
 		ACMEURL:   viper.GetString("acme_url"),
--- a/hscontrol/types/config_test.go
+++ b/hscontrol/types/config_test.go
@ -280,9 +280,9 @@ func TestReadConfigFromEnv(t *testing.T) {
 						// "foo.bar.com": {"1.1.1.1"},
 					},
 				},
-				ExtraRecords: []tailcfg.DNSRecord{
-					// {Name: "prometheus.myvpn.example.com", Type: "A", Value: "100.64.0.4"},
-				},
+				// ExtraRecords: []tailcfg.DNSRecord{
+				// 	{Name: "prometheus.myvpn.example.com", Type: "A", Value: "100.64.0.4"},
+				// },
 				SearchDomains: []string{"test.com", "bar.com"},
 			},
 		},
--- a/hscontrol/util/dns.go
+++ b/hscontrol/util/dns.go
@ -189,7 +189,6 @@ func GenerateIPv6DNSRootDomain(ipPrefix netip.Prefix) []dnsname.FQDN {
 // NormalizeToFQDNRules will replace forbidden chars in user
 // it can also return an error if the user doesn't respect RFC 952 and 1123.
 func NormalizeToFQDNRules(name string, stripEmailDomain bool) (string, error) {
-
 	name = strings.ToLower(name)
 	name = strings.ReplaceAll(name, "'", "")
 	atIdx := strings.Index(name, "@")
--- a/integration/auth_oidc_test.go
+++ b/integration/auth_oidc_test.go
@ -154,7 +154,7 @@ func TestOIDCAuthenticationPingAll(t *testing.T) {
 	}

 	sort.Slice(listUsers, func(i, j int) bool {
-		return listUsers[i].Id < listUsers[j].Id
+		return listUsers[i].GetId() < listUsers[j].GetId()
 	})

 	if diff := cmp.Diff(want, listUsers, cmpopts.IgnoreUnexported(v1.User{}), cmpopts.IgnoreFields(v1.User{}, "CreatedAt")); diff != "" {
@ -514,7 +514,7 @@ func TestOIDC024UserCreation(t *testing.T) {
 			assertNoErr(t, err)

 			sort.Slice(listUsers, func(i, j int) bool {
-				return listUsers[i].Id < listUsers[j].Id
+				return listUsers[i].GetId() < listUsers[j].GetId()
 			})

 			if diff := cmp.Diff(want, listUsers, cmpopts.IgnoreUnexported(v1.User{}), cmpopts.IgnoreFields(v1.User{}, "CreatedAt")); diff != "" {
--- a/integration/dns_test.go
+++ b/integration/dns_test.go
@ -1,6 +1,7 @@
 package integration

 import (
+	"encoding/json"
 	"fmt"
 	"strings"
 	"testing"
@ -9,6 +10,7 @@ import (
 	"github.com/juanfont/headscale/integration/hsic"
 	"github.com/juanfont/headscale/integration/tsic"
 	"github.com/stretchr/testify/assert"
+	"tailscale.com/tailcfg"
 )

 func TestResolveMagicDNS(t *testing.T) {
@ -81,6 +83,93 @@ func TestResolveMagicDNS(t *testing.T) {
 	}
 }

+func TestResolveMagicDNSExtraRecordsPath(t *testing.T) {
+	IntegrationSkip(t)
+	t.Parallel()
+
+	scenario, err := NewScenario(dockertestMaxWait())
+	assertNoErr(t, err)
+	defer scenario.ShutdownAssertNoPanics(t)
+
+	spec := map[string]int{
+		"magicdns1": 1,
+		"magicdns2": 1,
+	}
+
+	const erPath = "/tmp/extra_records.json"
+
+	extraRecords := []tailcfg.DNSRecord{
+		{
+			Name:  "test.myvpn.example.com",
+			Type:  "A",
+			Value: "6.6.6.6",
+		},
+	}
+	b, _ := json.Marshal(extraRecords)
+
+	err = scenario.CreateHeadscaleEnv(spec, []tsic.Option{
+		tsic.WithDockerEntrypoint([]string{
+			"/bin/sh",
+			"-c",
+			"/bin/sleep 3 ; apk add python3 curl bind-tools ; update-ca-certificates ; tailscaled --tun=tsdev",
+		}),
+	},
+		hsic.WithTestName("extrarecords"),
+		hsic.WithConfigEnv(map[string]string{
+			// Disable global nameservers to make the test run offline.
+			"HEADSCALE_DNS_NAMESERVERS_GLOBAL": "",
+			"HEADSCALE_DNS_EXTRA_RECORDS_PATH": erPath,
+		}),
+		hsic.WithFileInContainer(erPath, b),
+		hsic.WithEmbeddedDERPServerOnly(),
+		hsic.WithTLS(),
+		hsic.WithHostnameAsServerURL(),
+	)
+	assertNoErrHeadscaleEnv(t, err)
+
+	allClients, err := scenario.ListTailscaleClients()
+	assertNoErrListClients(t, err)
+
+	err = scenario.WaitForTailscaleSync()
+	assertNoErrSync(t, err)
+
+	// assertClientsState(t, allClients)
+
+	// Poor mans cache
+	_, err = scenario.ListTailscaleClientsFQDNs()
+	assertNoErrListFQDN(t, err)
+
+	_, err = scenario.ListTailscaleClientsIPs()
+	assertNoErrListClientIPs(t, err)
+
+	for _, client := range allClients {
+		assertCommandOutputContains(t, client, []string{"dig", "test.myvpn.example.com"}, "6.6.6.6")
+	}
+
+	extraRecords = append(extraRecords, tailcfg.DNSRecord{
+		Name:  "otherrecord.myvpn.example.com",
+		Type:  "A",
+		Value: "7.7.7.7",
+	})
+	b2, _ := json.Marshal(extraRecords)
+
+	hs, err := scenario.Headscale()
+	assertNoErr(t, err)
+
+	// Write it to a separate file to ensure Docker's API doesnt
+	// do anything unexpected and rather move it into place to trigger
+	// a reload.
+	err = hs.WriteFile(erPath+"2", b2)
+	assertNoErr(t, err)
+	_, err = hs.Execute([]string{"mv", erPath + "2", erPath})
+	assertNoErr(t, err)
+
+	for _, client := range allClients {
+		assertCommandOutputContains(t, client, []string{"dig", "test.myvpn.example.com"}, "6.6.6.6")
+		assertCommandOutputContains(t, client, []string{"dig", "otherrecord.myvpn.example.com"}, "7.7.7.7")
+	}
+}
+
 // TestValidateResolvConf validates that the resolv.conf file
 // ends up as expected in our Tailscale containers.
 // All the containers are based on Alpine, meaning Tailscale
--- a/integration/utils.go
+++ b/integration/utils.go
@ -3,6 +3,7 @@ package integration
 import (
 	"bufio"
 	"bytes"
+	"fmt"
 	"io"
 	"os"
 	"strings"
@ -10,6 +11,7 @@ import (
 	"testing"
 	"time"

+	"github.com/cenkalti/backoff/v4"
 	"github.com/juanfont/headscale/hscontrol/util"
 	"github.com/juanfont/headscale/integration/tsic"
 	"github.com/stretchr/testify/assert"
@ -302,6 +304,30 @@ func assertValidNetcheck(t *testing.T, client TailscaleClient) {
 	assert.NotEqualf(t, 0, report.PreferredDERP, "%q does not have a DERP relay", client.Hostname())
 }

+// assertCommandOutputContains executes a command for a set time and asserts that the output
+// reaches a desired state.
+// It should be used instead of sleeping before executing.
+func assertCommandOutputContains(t *testing.T, c TailscaleClient, command []string, contains string) {
+	t.Helper()
+
+	err := backoff.Retry(func() error {
+		stdout, stderr, err := c.Execute(command)
+		if err != nil {
+			return fmt.Errorf("executing command, stdout: %q stderr: %q, err: %w", stdout, stderr, err)
+		}
+
+		if !strings.Contains(stdout, contains) {
+			return fmt.Errorf("executing command, expected string %q not found in %q", contains, stdout)
+		}
+
+		return nil
+	}, backoff.NewExponentialBackOff(
+		backoff.WithMaxElapsedTime(10*time.Second)),
+	)
+
+	assert.NoError(t, err)
+}
+
 func isSelfClient(client TailscaleClient, addr string) bool {
 	if addr == client.Hostname() {
 		return true