Fix race condition in kubectl run --attach

pkg/kubectl/cmd/attach.go

@@ -156,12 +156,6 @@ func (p *AttachOptions) Run() error {
 		return fmt.Errorf("pod %s is not running and cannot be attached to; current phase is %s", p.PodName, pod.Status.Phase)
 	}
 
-	containerName := p.ContainerName
-	if len(containerName) == 0 {
-		glog.V(4).Infof("defaulting container name to %s", pod.Spec.Containers[0].Name)
-		containerName = pod.Spec.Containers[0].Name
-	}
-
 	// TODO: refactor with terminal helpers from the edit utility once that is merged
 	var stdin io.Reader
 	tty := p.TTY
@@ -205,7 +199,17 @@ func (p *AttachOptions) Run() error {
 		Name(pod.Name).
 		Namespace(pod.Namespace).
 		SubResource("attach").
-		Param("container", containerName)
+		Param("container", p.GetContainerName(pod))
 
 	return p.Attach.Attach(req, p.Config, stdin, p.Out, p.Err, tty)
 }
+
+// GetContainerName returns the name of the container to attach to, with a fallback.
+func (p *AttachOptions) GetContainerName(pod *api.Pod) string {
+	if len(p.ContainerName) > 0 {
+		return p.ContainerName
+	}
+
+	glog.V(4).Infof("defaulting container name to %s", pod.Spec.Containers[0].Name)
+	return pod.Spec.Containers[0].Name
+}

pkg/kubectl/cmd/run.go

@@ -291,12 +291,16 @@ func handleAttachPod(c *client.Client, pod *api.Pod, opts *AttachOptions) error
 		return err
 	}
 	if status == api.PodSucceeded || status == api.PodFailed {
-		return handleLog(c, pod.Namespace, pod.Name, &api.PodLogOptions{Container: pod.Spec.Containers[0].Name}, opts.Out)
+		return handleLog(c, pod.Namespace, pod.Name, &api.PodLogOptions{Container: opts.GetContainerName(pod)}, opts.Out)
 	}
 	opts.Client = c
 	opts.PodName = pod.Name
 	opts.Namespace = pod.Namespace
-	return opts.Run()
+	if err := opts.Run(); err != nil {
+		fmt.Fprintf(opts.Out, "Error attaching, falling back to logs: %v\n", err)
+		return handleLog(c, pod.Namespace, pod.Name, &api.PodLogOptions{Container: opts.GetContainerName(pod)}, opts.Out)
+	}
+	return nil
 }
 
 func getRestartPolicy(cmd *cobra.Command, interactive bool) (api.RestartPolicy, error) {