7. Service of such injunction and of all proceedings preliminary to or in connection therewith shall be made personally upon the owner, or other person or persons against whom it is directed, if they can be found in the district. If they cannot be so found, a copy thereof shall be delivered to any reasonable person residing in said building, and to the agent, if any, of the owner. If no such reasonable person be found, or service cannot be had upon such agent, if any, then service shall be made as the court shall direct.