DNS discovery is not used when ipa client is installed against a specific server. Post installation, it can be changed only by manual edit of config files or by reinstalling client.
Proposal: introduce a command which will allow to change it - from specific server to DNS discovery and vice versa.
Metadata Update from @pvoborni: - Issue assigned to someone - Issue set to the milestone: Future Releases
I imagine this would also fall under making the client installer idempotent so changes could be applied.
Metadata Update from @rcritten: - Issue close_status updated to: None