Template with Cloud-Init disk does not work properly after upgrade.

No - single node installation. Should I reboot system after update or restart any service?
No, reboot should not be required. Services are normally restarted automaitcally, but, if you had a connection open to the API (e.g., by having the GUI open in the browser) you may want to refresh that one completely, as the worker which handles the connection is then probably an old one, still using the old code.
 

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