By checking your log file, I realized that there was a mistake in request parameters. We did a commit recently to improve the software release but the documentation was not updated properly. Sorry, this is just a problem of tipo.
In your request parameters, section "REQUEST SLAPOS MASTER INSTANCE" please change this:
parameter_dict["certificate-authority-path"] = ca_path by parameter_dict["shared-certificate-authority-path"] = ca_path and request your instance like you did at the first time to update parameters.
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.
By applying the changes, your instance will be reprocessed but not all important processes will be restarted. Stop your instance and wait about 5 minutes then start again your instance. The problem will be fixed.
Check that "certificate authority folder" is not empty and that it contain the file "cacert.pem". When you confirm that all are OK, you can continue the documentation at the point "FIX CERTIFICATE AUTHORITY PATH".
I modified the documentation to fix the parameter name.
Please continue your deployment like you started to do. If you want, you can try later the deployment with webrunner, but both cases should work we are doing our best to fix all possibles issues. By using it, you help us to improve the software and the documentation too.