If you have been running the Android O Developer Preview 1 over the past few weeks on the Pixel and Pixel XL you have been doing so without root since there has previously been no root method. Today that changes! Pixel user Sachi31 discovered and posted a new root method for Android O. Apparently the method requires you to install Android 7.1.2 on one slot and Android O DP1 on another. Android O is allowed to fully boot once root is installed. There is a complete guide at the link below. If you are in to this sort of thing have fun!
via XDA
