Automatic merge from submit-queue
Handle federated service name lookups in kube-dns.
For the domain name queries that fail to match any records in the local
kube-dns cache, we check if the queried name matches the federation
pattern. If it does, we send a CNAME response to the federated name.
For more details look at the comments in the code.
Tests are coming ...
Also, this PR is based on @ArtfulCoder's PR #23930. So please review only the last commit here.
PTAL @ArtfulCoder @thockin @quinton-hoole @nikhiljindal
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