To stick with the traditional pomodoro technique this is considered an interruption. Pomodoro technique is made so that you shouldn't be thinking about the kettle on the stove at all! Tracking down internal interruptions is an inverse way to track your progress in not triggering interruption yourself. Zero internal interruptions => you are completely focused on what you are doing and you achieved one of the goals of the technique.
If you want to get the iron-hard focusing capability that the technique promises, you should stop the pomodoro right there and handle that or write it down on a piece of paper and handle it later. On a less strict interpretation, of course you can handle your problem immediately, it depends on what you want to achieve using this technique.
The downvote made me think... What is wrong in what I said? Now I understand an important thing that I forgot to mention about my appilcation of the pomodoro technique. In the startup phase I usually make my environment comfortable before starting to work. That means also removing any kettle that would be on the stove before starting, and, more generally, removing all possible interruption-generators I can find.
Of course you can implement the technique the way you want, but I suggest you to look for the implementation that makes you reach the best results! This is the crucial point of this technique: continuous improvement. Look for the behaviour that suites more your concentration, either setting up your environment or focusing on your task and handling possible interruptions during pomodoros.