Although the 'validate' param was added for the deployment of
/etc/nginx.conf - this validation process will only be triggered upon
changes.
So, if a vhost config is updated, but the main config isn't, the
collective config will not be verified.
I've added a new handler 'validate nginx configuration' and added this
to the 'notify' param as a first list item for vhost config changes.
Unfortunately, this will not protect against the deployment of malformed
configuration, however it will prevent the restart of Nginx in such a
situation (as the 'validate nginx configuration' handler should error
out before the 'restart nginx' handler is called).
cmacrae
Jeff Geerling