Fruit contains a lot of sugar, that is not only harmful to ketosis but can actually promote inflammation. Most fruits should be avoided to properly follow a Ketogenic Diet.
There are some fruits that are lower glycemic that can fit into a Ketogenic Diet in moderation such as avocado, coconut, and certain berries. Like all foods, check the nutrition label or your nutrition tracking app to see the carb content on fruit before choosing which ones to consume.