Support user specified `SubDomain` in Swan

[xychu]

Currently swan name Apps as <appName>.<runAs>.<clusterName>, is it possible to support user specified SubDomain as <appName>.<runAs>.<subDomain or clusterName if no subDomain given> ?

We'd like to use this field to subset user Apps.

[cmingxu]

@xychu Honestly involve another concept subDomain doesn't need much dev work base on current code base and as a DNS proxy should support flexible domain naturally.

My concern is how to make Swan user understand this additional concept, how to mix this new thing into our existing concepts seamlessly not confusing our user.

[xychu]

@cmingxu, I understand your concern. No need to rush into a decision. :-)

[xychu]

IMPO, it's not a whole new thing, more like give user the ability to configure the third part of the existing App name struct. We just need to give it a "Name", for me it's like a domain or subdomain.

[xiaods]

hi team, i dont' think this is issue. the is domain define. please consider swan world's define, please talk about more information.

[xiaods]

this domain is specified in swan world. don't need cover by mesos settings.