Allow multiple RFC2136 zones

kubernetes-sigs · Oct 8, 2023 · 4794c01 · 4794c01
1 parent bc22050
commit 4794c01
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Showing 4 changed files with 58 additions and 34 deletions.
diff --git a/docs/tutorials/rfc2136.md b/docs/tutorials/rfc2136.md
@@ -227,6 +227,7 @@ spec:
         - --rfc2136-host=192.168.0.1
         - --rfc2136-port=53
         - --rfc2136-zone=k8s.example.org
+        - --rfc2136-zone=k8s.your-zone.org
         - --rfc2136-tsig-secret=96Ah/a2g0/nLeFGK+d/0tzQcccf9hCEIy34PoXX2Qg8=
         - --rfc2136-tsig-secret-alg=hmac-sha256
         - --rfc2136-tsig-keyname=externaldns-key
@@ -269,6 +270,7 @@ spec:
         - --rfc2136-host=192.168.0.1
         - --rfc2136-port=53
         - --rfc2136-zone=k8s.example.org
+        - --rfc2136-zone=k8s.your-zone.org
         - --rfc2136-tsig-secret=96Ah/a2g0/nLeFGK+d/0tzQcccf9hCEIy34PoXX2Qg8=
         - --rfc2136-tsig-secret-alg=hmac-sha256
         - --rfc2136-tsig-keyname=externaldns-key
@@ -299,6 +301,7 @@ You'll want to configure `external-dns` similarly to the following:
         - --rfc2136-host=192.168.0.1
         - --rfc2136-port=53
         - --rfc2136-zone=k8s.example.org
+        - --rfc2136-zone=k8s.your-zone.org
         - --rfc2136-insecure
         - --rfc2136-tsig-axfr # needed to enable zone transfers, which is required for deletion of records.
 ...
@@ -384,6 +387,7 @@ You'll want to configure `external-dns` similarly to the following:
         - --rfc2136-host=dns-host.yourdomain.com
         - --rfc2136-port=53
         - --rfc2136-zone=your-zone.com
+        - --rfc2136-zone=your-secondary-zone.com
         - --rfc2136-kerberos-username=your-domain-account
         - --rfc2136-kerberos-password=your-domain-password
         - --rfc2136-kerberos-realm=your-domain.com

diff --git a/pkg/apis/externaldns/types.go b/pkg/apis/externaldns/types.go
@@ -175,7 +175,7 @@ type Config struct {
 	ResolveServiceLoadBalancerHostname bool
 	RFC2136Host                        string
 	RFC2136Port                        int
-	RFC2136Zone                        string
+	RFC2136Zone                        []string
 	RFC2136Insecure                    bool
 	RFC2136GSSTSIG                     bool
 	RFC2136KerberosRealm               string
@@ -330,7 +330,7 @@ var defaultConfig = &Config{
 	CFPassword:                  "",
 	RFC2136Host:                 "",
 	RFC2136Port:                 0,
-	RFC2136Zone:                 "",
+	RFC2136Zone:                 []string{},
 	RFC2136Insecure:             false,
 	RFC2136GSSTSIG:              false,
 	RFC2136KerberosRealm:        "",
@@ -558,7 +558,7 @@ func (cfg *Config) ParseFlags(args []string) error {
 	// Flags related to RFC2136 provider
 	app.Flag("rfc2136-host", "When using the RFC2136 provider, specify the host of the DNS server").Default(defaultConfig.RFC2136Host).StringVar(&cfg.RFC2136Host)
 	app.Flag("rfc2136-port", "When using the RFC2136 provider, specify the port of the DNS server").Default(strconv.Itoa(defaultConfig.RFC2136Port)).IntVar(&cfg.RFC2136Port)
-	app.Flag("rfc2136-zone", "When using the RFC2136 provider, specify the zone entry of the DNS server to use").Default(defaultConfig.RFC2136Zone).StringVar(&cfg.RFC2136Zone)
+	app.Flag("rfc2136-zone", "When using the RFC2136 provider, specify zone entries of the DNS server to use").StringsVar(&cfg.RFC2136Zone)
 	app.Flag("rfc2136-insecure", "When using the RFC2136 provider, specify whether to attach TSIG or not (default: false, requires --rfc2136-tsig-keyname and rfc2136-tsig-secret)").Default(strconv.FormatBool(defaultConfig.RFC2136Insecure)).BoolVar(&cfg.RFC2136Insecure)
 	app.Flag("rfc2136-tsig-keyname", "When using the RFC2136 provider, specify the TSIG key to attached to DNS messages (required when --rfc2136-insecure=false)").Default(defaultConfig.RFC2136TSIGKeyName).StringVar(&cfg.RFC2136TSIGKeyName)
 	app.Flag("rfc2136-tsig-secret", "When using the RFC2136 provider, specify the TSIG (base64) value to attached to DNS messages (required when --rfc2136-insecure=false)").Default(defaultConfig.RFC2136TSIGSecret).StringVar(&cfg.RFC2136TSIGSecret)

diff --git a/provider/rfc2136/rfc2136.go b/provider/rfc2136/rfc2136.go
@@ -20,6 +20,7 @@ import (
 	"context"
 	"fmt"
 	"net"
+	"sort"
 	"strconv"
 	"strings"
 	"time"
@@ -45,7 +46,7 @@ const (
 type rfc2136Provider struct {
 	provider.BaseProvider
 	nameserver      string
-	zoneName        string
+	zoneName        []string
 	tsigKeyName     string
 	tsigSecret      string
 	tsigSecretAlg   string
@@ -81,19 +82,15 @@ type rfc2136Actions interface {
 }
 
 // NewRfc2136Provider is a factory function for OpenStack rfc2136 providers
-func NewRfc2136Provider(host string, port int, zoneName string, insecure bool, keyName string, secret string, secretAlg string, axfr bool, domainFilter endpoint.DomainFilter, dryRun bool, minTTL time.Duration, gssTsig bool, krb5Username string, krb5Password string, krb5Realm string, batchChangeSize int, actions rfc2136Actions) (provider.Provider, error) {
+func NewRfc2136Provider(host string, port int, zoneName []string, insecure bool, keyName string, secret string, secretAlg string, axfr bool, domainFilter endpoint.DomainFilter, dryRun bool, minTTL time.Duration, gssTsig bool, krb5Username string, krb5Password string, krb5Realm string, batchChangeSize int, actions rfc2136Actions) (provider.Provider, error) {
 	secretAlgChecked, ok := tsigAlgs[secretAlg]
 	if !ok && !insecure && !gssTsig {
 		return nil, errors.Errorf("%s is not supported TSIG algorithm", secretAlg)
 	}
 
-	if krb5Realm == "" {
-		krb5Realm = strings.ToUpper(zoneName)
-	}
-
 	r := &rfc2136Provider{
 		nameserver:      net.JoinHostPort(host, strconv.Itoa(port)),
-		zoneName:        dns.Fqdn(zoneName),
+		zoneName:        zoneName,
 		insecure:        insecure,
 		gssTsig:         gssTsig,
 		krb5Username:    krb5Username,
@@ -209,30 +206,32 @@ func (r rfc2136Provider) List() ([]dns.RR, error) {
 		return make([]dns.RR, 0), nil
 	}
 
-	log.Debugf("Fetching records for '%s'", r.zoneName)
+	records := make([]dns.RR, 0)
+	for _, zone := range r.zoneName {
+		log.Debugf("Fetching records for '%s'", zone)
 
-	m := new(dns.Msg)
-	m.SetAxfr(r.zoneName)
-	if !r.insecure && !r.gssTsig {
-		m.SetTsig(r.tsigKeyName, r.tsigSecretAlg, clockSkew, time.Now().Unix())
-	}
+		m := new(dns.Msg)
+		m.SetAxfr(dns.Fqdn(zone))
+		if !r.insecure && !r.gssTsig {
+			m.SetTsig(r.tsigKeyName, r.tsigSecretAlg, clockSkew, time.Now().Unix())
+		}
 
-	env, err := r.actions.IncomeTransfer(m, r.nameserver)
-	if err != nil {
-		return nil, fmt.Errorf("failed to fetch records via AXFR: %v", err)
-	}
+		env, err := r.actions.IncomeTransfer(m, r.nameserver)
+		if err != nil {
+			return nil, fmt.Errorf("failed to fetch records via AXFR: %v", err)
+		}
 
-	records := make([]dns.RR, 0)
-	for e := range env {
-		if e.Error != nil {
-			if e.Error == dns.ErrSoa {
-				log.Error("AXFR error: unexpected response received from the server")
-			} else {
-				log.Errorf("AXFR error: %v", e.Error)
+		for e := range env {
+			if e.Error != nil {
+				if e.Error == dns.ErrSoa {
+					log.Error("AXFR error: unexpected response received from the server")
+				} else {
+					log.Errorf("AXFR error: %v", e.Error)
+				}
+				continue
 			}
-			continue
+			records = append(records, e.RR...)
 		}
-		records = append(records, e.RR...)
 	}
 
 	return records, nil
@@ -248,14 +247,14 @@ func (r rfc2136Provider) ApplyChanges(ctx context.Context, changes *plan.Changes
 		log.Debugf("Processing batch %d of create changes", c)
 
 		m := new(dns.Msg)
-		m.SetUpdate(r.zoneName)
-
 		for _, ep := range chunk {
 			if !r.domainFilter.Match(ep.DNSName) {
 				log.Debugf("Skipping record %s because it was filtered out by the specified --domain-filter", ep.DNSName)
 				continue
 			}
 
+			findMsgZone(ep, m, &r)
+
 			r.AddRecord(m, ep)
 		}
 
@@ -274,14 +273,15 @@ func (r rfc2136Provider) ApplyChanges(ctx context.Context, changes *plan.Changes
 		log.Debugf("Processing batch %d of update changes", c)
 
 		m := new(dns.Msg)
-		m.SetUpdate(r.zoneName)
 
 		for i, ep := range chunk {
 			if !r.domainFilter.Match(ep.DNSName) {
 				log.Debugf("Skipping record %s because it was filtered out by the specified --domain-filter", ep.DNSName)
 				continue
 			}
 
+			findMsgZone(ep, m, &r)
+
 			r.UpdateRecord(m, changes.UpdateOld[i], ep)
 		}
 
@@ -300,14 +300,15 @@ func (r rfc2136Provider) ApplyChanges(ctx context.Context, changes *plan.Changes
 		log.Debugf("Processing batch %d of delete changes", c)
 
 		m := new(dns.Msg)
-		m.SetUpdate(r.zoneName)
 
 		for _, ep := range chunk {
 			if !r.domainFilter.Match(ep.DNSName) {
 				log.Debugf("Skipping record %s because it was filtered out by the specified --domain-filter", ep.DNSName)
 				continue
 			}
 
+			findMsgZone(ep, m, &r)
+
 			r.RemoveRecord(m, ep)
 		}
 
@@ -439,3 +440,22 @@ func chunkBy(slice []*endpoint.Endpoint, chunkSize int) [][]*endpoint.Endpoint {
 
 	return chunks
 }
+
+func findMsgZone(ep *endpoint.Endpoint, m *dns.Msg, r *rfc2136Provider) {
+	sort.Slice(r.zoneName, func(i, j int) bool {
+		return len(strings.Split(r.zoneName[i], ".")) > len(strings.Split(r.zoneName[j], "."))
+	})
+
+	for _, zone := range r.zoneName {
+		if strings.HasSuffix(ep.DNSName, zone) {
+			r.krb5Realm = strings.ToUpper(dns.Fqdn(zone))
+			m.SetUpdate(dns.Fqdn(zone))
+
+			return
+		}
+	}
+
+	log.Debugf("No avialable zone found for %s, set it to 'root'", ep.DNSName)
+	r.krb5Realm = dns.Fqdn(".")
+	m.SetUpdate(dns.Fqdn("."))
+}
diff --git a/provider/rfc2136/rfc2136_test.go b/provider/rfc2136/rfc2136_test.go
@@ -95,7 +95,7 @@ func (r *rfc2136Stub) IncomeTransfer(m *dns.Msg, a string) (env chan *dns.Envelo
 }
 
 func createRfc2136StubProvider(stub *rfc2136Stub) (provider.Provider, error) {
-	return NewRfc2136Provider("", 0, "", false, "key", "secret", "hmac-sha512", true, endpoint.DomainFilter{}, false, 300*time.Second, false, "", "", "", 50, stub)
+	return NewRfc2136Provider("", 0, []string{}, false, "key", "secret", "hmac-sha512", true, endpoint.DomainFilter{}, false, 300*time.Second, false, "", "", "", 50, stub)
 }
 
 func extractAuthoritySectionFromMessage(msg fmt.Stringer) []string {