How important is knowing German before moving there?

Thanks to everyone who replied to my last post about choosing Germany over other countries. It really helped me narrow things down, and I'm leaning even more towards Germany now.

One thing I'm still unsure about is the language. I know many master's programs are in English, but how much German do you realistically need during your first few months?

Would you recommend reaching A1, A2, or even B1 before moving, or is it manageable to learn after arriving?