Bulgakov himself lived for a while in Bolshaya Sadovaya ulitsa number 10 in Moscow with his second wife. From the residents' list of that building we can learn that he shared apartment number 50 with other people.
The shortage of living space after the revolution created the typiscal Soviet phenomenon of коммунальная квартира (kommunalnaya kwartira) or communal apartment in which families had one or two rooms for themselves, and shared the kitchen and the bathroom with other families. Often there would be resentment between the various families living in one communal apartment.
This phenomenon is beautifully described in the movie picture Doctor Zhivago from the British director David Lean with Omar Sharif, Julie Christie and Geraldine Chaplin from 1965. In this scene the doctor returns from the front and sees how the bolsheviks divided his house into living spaces for several families.