Create the keyfile for Internal Authentication
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Enabling Auth for Security
Generate keyfile for the machine you are working with
Mac
Create the file if you are on mac and running as a container
$ openssl rand -base64 741 >> mongoKeyFileMac
$ chmod 600 mongoKeyFileMac
Linux
Create the file if you are on linux and running as a container
$ openssl rand -base64 756 > mongoKeyFileLinux
$ chmod 600 mongoKeyFileLinux
$ sudo chown 999 mongoKeyFileLinux
$ sudo chgrp 999 mongoKeyFileLinux
Reference