It's a bit awkward here that you use the presence or absence of configs to enabled different rolling strategies. What about something more explicit:
```
spark.executor.logs.rolling.enabled: true/[false]
spark.executor.logs.rolling.strategy: time/[size]
spark.executor.logs.rolling.time.interval: [daily]
spark.executor.logs.rolling.maxRetainedFiles: [none]
spark.executor.logs.rolling.size.maxBytes: [1024 * 1024]
```

My concern with the current approach is that when we add more options that affect time-based rolling, it will be weird that the `interval` option happens to enable time-based rolling. For instance, what if we add another option to customize the date format.