implement ssh wait for a VM

Signed-off-by: Chanwit Kaewkasi <chanwit@gmail.com>

cmd/ignite/run/start.go

@@ -2,6 +2,9 @@ package run
 
 import (
 	"fmt"
+	"github.com/weaveworks/ignite/pkg/apis/ignite"
+	"net"
+	"time"
 
 	"github.com/weaveworks/ignite/pkg/operations"
 	"github.com/weaveworks/ignite/pkg/preflight/checkers"
@@ -47,9 +50,41 @@ func Start(so *startOptions) error {
 		return err
 	}
 
+	if err := waitForSSH(so.vm, 10); err != nil {
+		return err
+	}
+
 	// If starting interactively, attach after starting
 	if so.Interactive {
 		return Attach(so.attachOptions)
 	}
 	return nil
 }
+
+func waitForSSH(vm *ignite.VM, seconds int) error {
+	// When --ssh is enabled, wait until SSH service started on port 22 at most N seconds
+	ssh := vm.Spec.SSH
+	if ssh != nil && ssh.Generate {
+		if len(vm.Status.IPAddresses) > 0 {
+			addr := vm.Status.IPAddresses[0].String() + ":22"
+			var err error
+			for i := 0; i < seconds*10; i++ {
+				conn, dialErr := net.DialTimeout("tcp", addr, 100*time.Millisecond)
+				if conn != nil {
+					defer conn.Close()
+					err = nil
+					break
+				}
+				err = dialErr
+				time.Sleep(100 * time.Millisecond)
+			}
+			if err != nil {
+				if err, ok := err.(*net.OpError); ok && err.Timeout() {
+					return fmt.Errorf("Tried connecting to SSH but timed out %s", err)
+				}
+			}
+		}
+	}
+
+	return nil
+}