Changing hostname will break authentication between client and server.

[yandod]

I applied this cookbook for the node under the Hosted Chef.
Well, After changed hostname, authentication got broken.

Chef Server seems generation hash based on hostname and key.
I think this cookbook should inform about that.

[mpasternacki]

Do you have your client name configured in /etc/chef/client.rb? My guess for the cause would be that it's unset, and then it defaults to client's hostname. You should either use -N name in the initial chef-client run, or set the name explicitly in client.rb. The chef-client cookbook takes care of that.