How Aaruni Becomes Rishi Uddalak?

During the reign of King Janmayjay, there lived a Guru named Ayuddhaumya. He had three main disciples – Aaruni, Upmanyu, and Ved.
This is the story of his first strudent, Aaruni.
One day, the Guru summoned Aaruni, “Son, the levees of the field have been damaged and the irrigation water is rushing out from the field. Please, go and repair the levee.”
Aaruni bowed to his Guru’s wish and went to the field. However, the work was more difficult than he thought. He tried several times but could not build a levee. Tired and exhausted, he thought of an idea. In place of the levee, he laid down, which blocked the water flow. He remained in this position the entire day.
When the evening came and Aaruni did not return, Ayuddhaumya was worried. He asked his disciples, “Where is Aaruni?” His disciples answered, “Sir, you sent him to build a levee in the field.” The teacher said, “Come, let us see where he has gone.”
When they reached the field, the Guru called out, “Aaruni! Aaruni! Where are you, son?”
When he heard his teacher calling out, Aaruni stood and came to him with folded hands, “Sir, I am here. I apologize for not paying my respects to you in the evening, but I could not leave the field. When I could not stop water from flowing out by any means, I laid in place of levee. When I heard you calling for me, I stood up and have come to you for service. Please accept my greetings. Command me, what can I do to serve you?”
The Guru was pleased with the selfless service of his student. He smiled and replied, “Son, you stood up after breaking the levee.
From now on, you will be known by a new name, Uddalak (the one who gets up after breaking things). When you could not build a levee, you laid in place of it. You did this great service to your Guru without worrying about food, drink, or physical comfort. Therefore, you will be also known as Kalyan. All Vedas and Dharmashastras will be learned by you automatically.”
With these blessings from his Guru, Aaruni bid farewell to the aashram and happily returned to his native town.
Then Aaruni becomes rishi Uddalak, who is father of famous mythological character Nachiketa.