*: stop using resolved tcp addr

We start to resolve host into tcp addrs since we generate
tcp based initial-cluster during srv discovery. However it
creates problems around tls and cluster verification. The
srv discovery only needs to use resolved the tcp addr to
find the local node. It does not have to resolve everything
and use the resolved addrs.

This fixes #2488 and #2226

discovery/srv.go

@@ -68,8 +68,8 @@ func SRVGetCluster(name, dns string, defaultToken string, apurls types.URLs) (st
 				n = fmt.Sprintf("%d", tempName)
 				tempName += 1
 			}
-			stringParts = append(stringParts, fmt.Sprintf("%s=%s%s", n, prefix, tcpAddr.String()))
-			log.Printf("discovery: Got bootstrap from DNS for %s at host %s to %s%s", service, host, prefix, tcpAddr.String())
+			stringParts = append(stringParts, fmt.Sprintf("%s=%s%s", n, prefix, host))
+			log.Printf("discovery: Got bootstrap from DNS for %s at %s%s", service, prefix, host)
 		}
 		return nil
 	}

etcdmain/config.go

@@ -15,7 +15,6 @@
 package etcdmain
 
 import (
-	"errors"
 	"flag"
 	"fmt"
 	"log"
@@ -26,7 +25,6 @@ import (
 	"github.com/coreos/etcd/etcdserver"
 	"github.com/coreos/etcd/pkg/cors"
 	"github.com/coreos/etcd/pkg/flags"
-	"github.com/coreos/etcd/pkg/netutil"
 	"github.com/coreos/etcd/pkg/transport"
 	"github.com/coreos/etcd/version"
 )
@@ -260,10 +258,6 @@ func (cfg *config) Parse(arguments []string) error {
 		return err
 	}
 
-	if err := cfg.resolveUrls(); err != nil {
-		return errors.New("cannot resolve DNS hostnames.")
-	}
-
 	if 5*cfg.TickMs > cfg.ElectionMs {
 		return fmt.Errorf("-election-timeout[%vms] should be at least as 5 times as -heartbeat-interval[%vms]", cfg.ElectionMs, cfg.TickMs)
 	}
@@ -279,10 +273,6 @@ func initialClusterFromName(name string) string {
 	return fmt.Sprintf("%s=http://localhost:2380,%s=http://localhost:7001", n, n)
 }
 
-func (cfg *config) resolveUrls() error {
-	return netutil.ResolveTCPAddrs(cfg.lpurls, cfg.apurls, cfg.lcurls, cfg.acurls)
-}
-
 func (cfg config) isNewCluster() bool          { return cfg.clusterState.String() == clusterStateFlagNew }
 func (cfg config) isProxy() bool               { return cfg.proxy.String() != proxyFlagOff }
 func (cfg config) isReadonlyProxy() bool       { return cfg.proxy.String() == proxyFlagReadonly }