support v3 discovery to bootstrap a new etcd cluster

CHANGELOG-3.6.md

@@ -35,6 +35,7 @@ See [code changes](https://github.com/etcd-io/etcd/compare/v3.5.0...v3.6.0).
 - Add [`etcd --experimental-max-learners`](https://github.com/etcd-io/etcd/pull/13377) flag to allow configuration of learner max membership.
 - Add [`etcd --experimental-enable-lease-checkpoint-persist`](https://github.com/etcd-io/etcd/pull/13508) flag to handle upgrade from v3.5.2 clusters with this feature enabled.
 - Add [`etcdctl make-mirror --rev`](https://github.com/etcd-io/etcd/pull/13519) flag to support incremental mirror.
+- Add [v3 discovery](https://github.com/etcd-io/etcd/pull/13635) to bootstrap a new etcd cluster.
 - Fix [non mutating requests pass through quotaKVServer when NOSPACE](https://github.com/etcd-io/etcd/pull/13435)
 - Fix [exclude the same alarm type activated by multiple peers](https://github.com/etcd-io/etcd/pull/13467).
 - Fix [Provide a better liveness probe for when etcd runs as a Kubernetes pod](https://github.com/etcd-io/etcd/pull/13399)

client/pkg/types/urlsmap.go

@@ -25,7 +25,7 @@ type URLsMap map[string]URLs
 
 // NewURLsMap returns a URLsMap instantiated from the given string,
 // which consists of discovery-formatted names-to-URLs, like:
-// mach0=http://1.1.1.1:2380,mach0=http://2.2.2.2::2380,mach1=http://3.3.3.3:2380,mach2=http://4.4.4.4:2380
+// mach0=http://1.1.1.1:2380,mach1=http://2.2.2.2::2380,mach2=http://3.3.3.3:2380
 func NewURLsMap(s string) (URLsMap, error) {
 	m := parse(s)
 

server/config/config.go

@@ -25,6 +25,7 @@ import (
 	"go.etcd.io/etcd/client/pkg/v3/transport"
 	"go.etcd.io/etcd/client/pkg/v3/types"
 	"go.etcd.io/etcd/pkg/v3/netutil"
+	"go.etcd.io/etcd/server/v3/etcdserver/api/v3discovery"
 	"go.etcd.io/etcd/server/v3/storage/datadir"
 	"go.opentelemetry.io/contrib/instrumentation/google.golang.org/grpc/otelgrpc"
 
@@ -34,12 +35,16 @@ import (
 
 // ServerConfig holds the configuration of etcd as taken from the command line or discovery.
 type ServerConfig struct {
-	Name           string
-	DiscoveryURL   string
-	DiscoveryProxy string
-	ClientURLs     types.URLs
-	PeerURLs       types.URLs
-	DataDir        string
+	Name              string
+	EnableV2Discovery bool
+	DiscoveryURL      string
+	DiscoveryProxy    string
+
+	DiscoveryCfg v3discovery.DiscoveryConfig
+
+	ClientURLs types.URLs
+	PeerURLs   types.URLs
+	DataDir    string
 	// DedicatedWALDir config will make the etcd to write the WAL to the WALDir
 	// rather than the dataDir/member/wal.
 	DedicatedWALDir string

server/embed/config.go

@@ -16,6 +16,7 @@ package embed
 
 import (
 	"fmt"
+	"go.etcd.io/etcd/server/v3/etcdserver/api/v3discovery"
 	"net"
 	"net/http"
 	"net/url"
@@ -61,6 +62,11 @@ const (
 	DefaultGRPCKeepAliveTimeout        = 20 * time.Second
 	DefaultDowngradeCheckTime          = 5 * time.Second
 
+	DefaultDiscoveryDialTimeout      = 2 * time.Second
+	DefaultDiscoveryRequestTimeOut   = 5 * time.Second
+	DefaultDiscoveryKeepAliveTime    = 2 * time.Second
+	DefaultDiscoveryKeepAliveTimeOut = 6 * time.Second
+
 	DefaultListenPeerURLs   = "http://localhost:2380"
 	DefaultListenClientURLs = "http://localhost:2379"
 
@@ -87,6 +93,8 @@ const (
 	// It's enabled by default.
 	DefaultStrictReconfigCheck = true
 
+	DefaultEnableV2Discovery = true
+
 	// maxElectionMs specifies the maximum value of election timeout.
 	// More details are listed in ../Documentation/tuning.md#time-parameters.
 	maxElectionMs = 50000
@@ -216,10 +224,14 @@ type Config struct {
 	DNSCluster            string `json:"discovery-srv"`
 	DNSClusterServiceName string `json:"discovery-srv-name"`
 	Dproxy                string `json:"discovery-proxy"`
-	Durl                  string `json:"discovery"`
-	InitialCluster        string `json:"initial-cluster"`
-	InitialClusterToken   string `json:"initial-cluster-token"`
-	StrictReconfigCheck   bool   `json:"strict-reconfig-check"`
+
+	EnableV2Discovery bool   `json:"enable-v2-discovery"`
+	Durl              string `json:"discovery"`
+	DiscoveryCfg      v3discovery.DiscoveryConfig
+
+	InitialCluster      string `json:"initial-cluster"`
+	InitialClusterToken string `json:"initial-cluster-token"`
+	StrictReconfigCheck bool   `json:"strict-reconfig-check"`
 
 	// AutoCompactionMode is either 'periodic' or 'revision'.
 	AutoCompactionMode string `json:"auto-compaction-mode"`
@@ -501,6 +513,14 @@ func NewConfig() *Config {
 		ExperimentalMaxLearners:                  membership.DefaultMaxLearners,
 
 		V2Deprecation: config.V2_DEPR_DEFAULT,
+
+		EnableV2Discovery: DefaultEnableV2Discovery,
+		DiscoveryCfg: v3discovery.DiscoveryConfig{
+			DialTimeout:      DefaultDiscoveryDialTimeout,
+			RequestTimeOut:   DefaultDiscoveryRequestTimeOut,
+			KeepAliveTime:    DefaultDiscoveryKeepAliveTime,
+			KeepAliveTimeout: DefaultDiscoveryKeepAliveTimeOut,
+		},
 	}
 	cfg.InitialCluster = cfg.InitialClusterFromName(cfg.Name)
 	return cfg

server/embed/etcd.go

@@ -175,8 +175,10 @@ func StartEtcd(inCfg *Config) (e *Etcd, err error) {
 		MaxWALFiles:                              cfg.MaxWalFiles,
 		InitialPeerURLsMap:                       urlsmap,
 		InitialClusterToken:                      token,
+		EnableV2Discovery:                        cfg.EnableV2Discovery,
 		DiscoveryURL:                             cfg.Durl,
 		DiscoveryProxy:                           cfg.Dproxy,
+		DiscoveryCfg:                             cfg.DiscoveryCfg,
 		NewCluster:                               cfg.IsNewCluster(),
 		PeerTLSInfo:                              cfg.PeerTLSInfo,
 		TickMs:                                   cfg.TickMs,
@@ -343,6 +345,19 @@ func print(lg *zap.Logger, ec Config, sc config.ServerConfig, memberInitialized
 		zap.String("auto-compaction-interval", sc.AutoCompactionRetention.String()),
 		zap.String("discovery-url", sc.DiscoveryURL),
 		zap.String("discovery-proxy", sc.DiscoveryProxy),
+
+		zap.String("discovery-dial-timeout", sc.DiscoveryCfg.DialTimeout.String()),
+		zap.String("discovery-request-timeout", sc.DiscoveryCfg.RequestTimeOut.String()),
+		zap.String("discovery-keepalive-time", sc.DiscoveryCfg.KeepAliveTime.String()),
+		zap.String("discovery-keepalive-timeout", sc.DiscoveryCfg.KeepAliveTimeout.String()),
+		zap.Bool("discovery-insecure-transport", sc.DiscoveryCfg.InsecureTransport),
+		zap.Bool("discovery-insecure-skip-tls-verify", sc.DiscoveryCfg.InsecureSkipVerify),
+		zap.String("discovery-cert", sc.DiscoveryCfg.CertFile),
+		zap.String("discovery-key", sc.DiscoveryCfg.KeyFile),
+		zap.String("discovery-cacert", sc.DiscoveryCfg.TrustedCAFile),
+		zap.String("discovery-user", sc.DiscoveryCfg.User),
+		zap.Bool("discovery-insecure-discovery", sc.DiscoveryCfg.InsecureDiscovery),
+
 		zap.String("downgrade-check-interval", sc.DowngradeCheckTime.String()),
 		zap.Int("max-learners", sc.ExperimentalMaxLearners),
 	)

server/etcdmain/config.go

@@ -186,11 +186,25 @@ func newConfig() *config {
 		"advertise-client-urls",
 		"List of this member's client URLs to advertise to the public.",
 	)
+	fs.BoolVar(&cfg.ec.EnableV2Discovery, "enable-v2-discovery", cfg.ec.EnableV2Discovery, "Enable to bootstrap the cluster using v2 discovery. Will be deprecated in v3.7, and be decommissioned in v3.8.")
 	fs.StringVar(&cfg.ec.Durl, "discovery", cfg.ec.Durl, "Discovery URL used to bootstrap the cluster.")
 	fs.Var(cfg.cf.fallback, "discovery-fallback", fmt.Sprintf("Valid values include %q", cfg.cf.fallback.Valids()))
 
+	fs.DurationVar(&cfg.ec.DiscoveryCfg.DialTimeout, "discovery-dial-timeout", cfg.ec.DiscoveryCfg.DialTimeout, "V3 discovery: dial timeout for client connections.")
+	fs.DurationVar(&cfg.ec.DiscoveryCfg.RequestTimeOut, "discovery-request-timeout", cfg.ec.DiscoveryCfg.RequestTimeOut, "V3 discovery: timeout for discovery requests (excluding dial timeout).")
+	fs.DurationVar(&cfg.ec.DiscoveryCfg.KeepAliveTime, "discovery-keepalive-time", cfg.ec.DiscoveryCfg.KeepAliveTime, "V3 discovery: keepalive time for client connections.")
+	fs.DurationVar(&cfg.ec.DiscoveryCfg.KeepAliveTimeout, "discovery-keepalive-timeout", cfg.ec.DiscoveryCfg.KeepAliveTimeout, "V3 discovery: keepalive timeout for client connections.")
+	fs.BoolVar(&cfg.ec.DiscoveryCfg.InsecureTransport, "discovery-insecure-transport", false, "V3 discovery: disable transport security for client connections.")
+	fs.BoolVar(&cfg.ec.DiscoveryCfg.InsecureDiscovery, "discovery-insecure-discovery", true, "V3 discovery: accept insecure SRV records describing discovery service endpoint.")
+	fs.BoolVar(&cfg.ec.DiscoveryCfg.InsecureSkipVerify, "discovery-insecure-skip-tls-verify", false, "V3 discovery: skip server certificate verification (CAUTION: this option should be enabled only for testing purposes).")
+	fs.StringVar(&cfg.ec.DiscoveryCfg.CertFile, "discovery-cert", "", "V3 discovery: identify secure client using this TLS certificate file.")
+	fs.StringVar(&cfg.ec.DiscoveryCfg.KeyFile, "discovery-key", "", "V3 discovery: identify secure client using this TLS key file.")
+	fs.StringVar(&cfg.ec.DiscoveryCfg.TrustedCAFile, "discovery-cacert", "", "V3 discovery: verify certificates of TLS-enabled secure servers using this CA bundle.")
+	fs.StringVar(&cfg.ec.DiscoveryCfg.User, "discovery-user", "", "V3 discovery: username[:password] for authentication (prompt if password is not supplied).")
+	fs.StringVar(&cfg.ec.DiscoveryCfg.Password, "discovery-password", "", "V3 discovery: password for authentication (if this option is used, --user option shouldn't include password).")
+
 	fs.StringVar(&cfg.ec.Dproxy, "discovery-proxy", cfg.ec.Dproxy, "HTTP proxy to use for traffic to discovery service.")
-	fs.StringVar(&cfg.ec.DNSCluster, "discovery-srv", cfg.ec.DNSCluster, "DNS domain used to bootstrap initial cluster.")
+	fs.StringVar(&cfg.ec.DNSCluster, "discovery-srv", cfg.ec.DNSCluster, "DNS domain used to bootstrap initial cluster or the domain name to query for SRV records describing v3 discovery endpoint.")
 	fs.StringVar(&cfg.ec.DNSClusterServiceName, "discovery-srv-name", cfg.ec.DNSClusterServiceName, "Service name to query when using DNS discovery.")
 	fs.StringVar(&cfg.ec.InitialCluster, "initial-cluster", cfg.ec.InitialCluster, "Initial cluster configuration for bootstrapping.")
 	fs.StringVar(&cfg.ec.InitialClusterToken, "initial-cluster-token", cfg.ec.InitialClusterToken, "Initial cluster token for the etcd cluster during bootstrap.")

server/etcdmain/etcd.go

@@ -17,6 +17,7 @@ package etcdmain
 import (
 	"encoding/json"
 	"fmt"
+
 	"net/http"
 	"os"
 	"path/filepath"
@@ -34,6 +35,7 @@ import (
 	"go.etcd.io/etcd/server/v3/etcdserver"
 	"go.etcd.io/etcd/server/v3/etcdserver/api/etcdhttp"
 	"go.etcd.io/etcd/server/v3/etcdserver/api/v2discovery"
+	"go.etcd.io/etcd/server/v3/etcdserver/api/v3discovery"
 	"go.etcd.io/etcd/server/v3/proxy/httpproxy"
 
 	"go.uber.org/zap"
@@ -318,7 +320,11 @@ func startProxy(cfg *config) error {
 
 		if cfg.ec.Durl != "" {
 			var s string
-			s, err = v2discovery.GetCluster(lg, cfg.ec.Durl, cfg.ec.Dproxy)
+			if cfg.ec.EnableV2Discovery {
+				s, err = v2discovery.GetCluster(lg, cfg.ec.Durl, cfg.ec.Dproxy)
+			} else {
+				s, err = v3discovery.GetCluster(lg, cfg.ec.Durl, &cfg.ec.DiscoveryCfg)
+			}
 			if err != nil {
 				return err
 			}

server/etcdmain/help.go

@@ -104,15 +104,41 @@ Clustering:
   --advertise-client-urls 'http://localhost:2379'
     List of this member's client URLs to advertise to the public.
     The client URLs advertised should be accessible to machines that talk to etcd cluster. etcd client libraries parse these URLs to connect to the cluster.
+  --enable-v2-discovery 'true'
+    Enable to bootstrap the cluster using v2 discovery. Will be deprecated in v3.7, and be decommissioned in v3.8.
   --discovery ''
     Discovery URL used to bootstrap the cluster.
+  --discovery-dial-timeout
+    V3 discovery: dial timeout for client connections.
+  --discovery-request-timeout
+    V3 discovery: timeout for discovery requests (excluding dial timeout).
+  --discovery-keepalive-time
+    V3 discovery: keepalive time for client connections.
+  --discovery-keepalive-timeout
+    V3 discovery: keepalive timeout for client connections.
+  --discovery-insecure-transport 'false'
+    V3 discovery: disable transport security for client connections.
+  --discovery-insecure-discovery
+    V3 discovery: accept insecure SRV records describing discovery service endpoint.
+  --discovery-insecure-skip-tls-verify
+    V3 discovery: skip server certificate verification (CAUTION: this option should be enabled only for testing purposes).
+  --discovery-cert
+    V3 discovery: identify secure client using this TLS certificate file.
+  --discovery-key
+    V3 discovery: identify secure client using this TLS key file.
+  --discovery-cacert
+    V3 discovery: verify certificates of TLS-enabled secure servers using this CA bundle.
+  --discovery-user
+    V3 discovery: username[:password] for authentication (prompt if password is not supplied).
+  --discovery-password
+    V3 discovery: password for authentication (if this option is used, --user option shouldn't include password).
   --discovery-fallback 'proxy'
     Expected behavior ('exit' or 'proxy') when discovery services fails.
     "proxy" supports v2 API only.
   --discovery-proxy ''
     HTTP proxy to use for traffic to discovery service.
   --discovery-srv ''
-    DNS srv domain used to bootstrap the cluster.
+    DNS srv domain used to bootstrap the cluster or the domain name to query for SRV records describing the v3 discovery endpoint.
   --discovery-srv-name ''
     Suffix to the dns srv name queried when bootstrapping.
   --strict-reconfig-check '` + strconv.FormatBool(embed.DefaultStrictReconfigCheck) + `'