I don't believe your assessment is correct. I very specifically said built-in. This remains true. If curious, we're on CentOS 7 specifically. I didn't say there aren't any options, only that there aren't any built-in. What you described as alternatives are totally true, but they still aren't built-in. It's a manual/puppet/chef/etc. config everyone has to do.
As for the applications - we have little direct input to TeamCity of Gitlab (the problem children here). And even if we did, I think we agree: the application level shouldn't cache anyway.
That being said, we're looking at `dnscache` as one of a few solutions here. But the point remains: we have to do it.
You are employing a faulty concept of what constitutes built-in. This is not Windows, or one of the BSDs. You're using one of the Linux distributions where everything is made up of installing packages. There is no meaningful "built-in"/"not-built-in" difference between installing one of these DNS server packages from a CentOS 7 repository and installing any other CentOS packages from a CentOS 7 repository.
> All software on a Red Hat Enterprise Linux system is divided into RPM packages which can be installed, upgraded, or removed.
A (very) quick check indicates that the CentOS 7 "main" and "updates" repositories have at least three of the DNS softwares that I mentioned. Ubuntu 16 is better endowed, and has all of them that I mentioned, and an additional "Debian fork of djbdns" that I did not, in Ubuntu's "main" and "universe" repositories.
I too read that part of your post and paused. Your argument about it not being built into Linux is interesting because it gets down to what is Linux versus what is the distribution, etc. Which I don't think is worth getting into. The truth is I'm almost positive you rely on plenty of other core components not built into Linux proper. DNS caching is certainly available to you and if you don't have config mgmt or an immutable infrastructure model in place, I'd start considering it soon.
As for the applications - we have little direct input to TeamCity of Gitlab (the problem children here). And even if we did, I think we agree: the application level shouldn't cache anyway.
That being said, we're looking at `dnscache` as one of a few solutions here. But the point remains: we have to do it.