In the Raise A Ruckus Tonight song I have by Jean Ritchie it's pronounced rookus.

All them taters in the oven ummm ummm ummm
How I wish I had more of'm umm ummm ummm
Get on board, little children get on board
While the moon is shining bright
Get along little children get along
We're gonna raise a ruckus tonight

All them sweet potaters cookin umm umm ummm
I never seen'm so good lookin umm ummm ummm
Get on board...

and so on. Sounds a lot like the same song.