Question: I'm trying to write what must be the simplest angular directive which displays a Yes/No select list and is bound to a model containing a boolean value. Unfortunately the existing value is never preselected. My directive reads

```
  return {
        restrict: 'E',
        replace: true,
        template: '<select class="form-control"><option value="true">Yes</option><option value="false">No</option></select>',
        scope: {
              ngModel: '='
        }
  }

```

and I am calling the directive as

```
<yesno ng-model="brand.is_anchor"></yesno>

```

The select options display and the generated HTML reads as

```
<select class="form-control ng-isolate-scope ng-valid" ng-model="brand.is_anchor">
    <option value="? boolean:false ?"></option>
    <option value="true">Yes</option>
    <option value="false">No</option>
</select>

```

The initial value of the bound model is "false" but it always displays an empty option and per the first option listed in the generated HTML.

Can anybody please advise?

Answer: 
I have this configuration example here using docker compose that can be of help.

<https://github.com/oneyottabyte/redis_sentinel>
So, the solution that worked for me is simply reading the /etc/hosts file on the source container. I busy wait till the link is established and then use that network interface IP to start the sentinel process. This is just a stop gap solution and it is not scalable. Redis-sentinel is still not production ready in dockerizable format as confirmed in this [post](https://stackoverflow.com/questions/25914814/redis-sentinel-docker-image-dockerfile%20post). So I decided to install Redis/sentinel on the physical hosts.