Forgot to mention this -
> If you want, you can also edit that parameter from vifib.com / slapos.org interface. Go to you instance, search "certificate-authority-path" in your instance XML and replace by "shared-certificate-authority-path". Finally, click on "Update XML" to apply changes.
The ability to 'Update XML' is not available on vifib.com but works only on slapos.org as of now.