Modern Python Standard Library Cookbook

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multiprocessing.Manager is not constrained to work with processes that originated from the same process.

It's possible to create a Manager that will listen on a network so that any process that is able to connect to it might be able to access its content:

>>> import multiprocessing.managers
>>> manager = multiprocessing.managers.SyncManager(
...     address=('localhost', 50000), 
...     authkey=b'secret'
... )
>>> print(manager.address)
('localhost', 50000)

Then, once the server is started:

>>> manager.get_server().serve_forever()

The other processes will be able to connect to it by creating a manager2 instance with the exact same arguments of the manager they want to connect to, and then explicitly connect:

>>> manager2 = multiprocessing.managers.SyncManager( ...