k8s_external can now resolve CNAME returned by AWS ELB/NLB (#3916)

Automatically submitted.

plugin/k8s_external/setup.go

@@ -5,6 +5,7 @@ import (
 
 	"github.com/coredns/coredns/core/dnsserver"
 	"github.com/coredns/coredns/plugin"
+	"github.com/coredns/coredns/plugin/pkg/upstream"
 
 	"github.com/caddyserver/caddy"
 )
@@ -30,6 +31,8 @@ func setup(c *caddy.Controller) error {
 		return nil
 	})
 
+	e.upstream = upstream.New()
+
 	dnsserver.GetConfig(c).AddPlugin(func(next plugin.Handler) plugin.Handler {
 		e.Next = next
 		return e