Compact, low-noise microwave oscillators are required throughout a wide range of applications such as radar systems, wireless networks, and frequency metrology. Optical frequency division via an optical frequency comb provides a powerful tool for low-noise microwave signal generation. Here, we experimentally demonstrate an optical reference down to 26 GHz frequency division based on the dissipative Kerr soliton comb, which is generated on a CMOS-compatible, high-index doped silica glass platform. The optical reference is generated through two continuous wave lasers locked to an ultralow expansion cavity. The dissipative Kerr soliton comb with a repetition rate of 26 GHz acts as a frequency divider to derive an ultralow-noise microwave oscillator, with a phase noise level of -101.3 dBc/Hz at a 100 Hz offset frequency and -132.4 dBc/Hz at a 10 kHz offset frequency. Furthermore, the Allan deviation of the oscillator reaches 6.4 x 10(-13) at a 1 s measurement time. Our system is expected to provide an ultralow-noise microwave oscillator for future radar systems and the next generation of wireless networks.