HTTP Load-balanced Logbook Application sample: failed to pick backend after deployment

Following the example to create a deployment of [HTTP Load-balanced Logbook Application](https://cloud.google.com/deployment-manager/docs/create-advanced-http-load-balanced-deployment), after deployment is successfully created, the forwarding rule cannot find a healthy backend to use. After I get to step to [test configuration](https://cloud.google.com/deployment-manager/docs/create-advanced-http-load-balanced-deployment#test_your_configuration), the requests return
```
502: The server encountered a temporary error and could not complete your request.

Please try again in 30 seconds.
```


Digging deeper into stackdriver logs I'm seeing `failed_to_pick_backend`