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Should CNAME Be Used For Subdomains?

ayi

I manage multiple websites that currently have the following DNS configuration:
<pre><code class="lang-auto">example.com - A Record - Production Server IP
test.example.com - A Record - Test Server IP
www.example.com - CNAME - example.com
beta.example.com - CNAME - test.example.com
dev.example.com - CNAME - test.example.com

</code></pre>
Is this an appropriate use of CNAME records? I’ve looked online and have not found a clear answer. Some people claim that CNAME records are bad (they are not, however, clear on why this is) and propose the following setup:
<pre><code class="lang-auto">example.com - A Record - Production Server IP
test.example.com - A Record - Test Server IP
www.example.com - A Record - Production Server IP
beta.example.com - A Record - Test Server IP
dev.example.com - A Record - Test Server IP

</code></pre>
Which one of these is the better approach (and why)?
Note : The subdomains do not require their own MX records, so that is not an issue here.
<hr>
Source : <a href="http://web.archive.org/web/20110809095548/https://serverfault.com/questions/45734/the-coolest-server-names" rel="noopener nofollow ugc">Server Fault</a>.)

ayi_2

Yes, that’s an appropriate use of CNAMEs. In the discussions I’ve been part of, the arguments tend to go like this:
Against CNAMEs:
<ul>
<li>
There is a (tiny) performance penalty, as the downstream DNS caches need to perform 2 DNS lookups, one for the CNAME and one for the A-Record the CNAME points to.
</li>
<li>
Vague, bogus arguments about CNAMEs having less “authority” or compatibility issues.
</li>
</ul>
In favor of CNAMEs:
<ul>
<li>
They provide a clean abstraction between hardware (physical servers) and services.
</li>
<li>
They simplify DNS management – when a server moves, you only need to change one record.
</li>
</ul>
After trying a couple of different ways to do this, I now have a personal favorite style. It is:
<ul>
<li>
One A Record for each physical server; with a fairly low TTL (perhaps 30 minutes); giving the server a <a href="http://web.archive.org/web/20110809095548/https://serverfault.com/questions/45734/the-coolest-server-names">human-friendly name</a>.
</li>
<li>
One CNAME for each service; with a high TTL (perhaps 24 hours); pointing to the above server names.
</li>
<li>
As the sole exeption to the rules above, the domain root is an A-Record, pointing to the webserver / web load balancer. (The @ is required to be an A-record.)
</li>
</ul>
I find that this setup works well. It keeps extra DNS lookups for the CNAMES down; and if a server crashes I can still change public DNS around fairly fast.
Here’s a (improvised) example in BIND syntax:
<pre><code class="lang-auto">;name ttl class rr value
server01 30m IN A 192.168.0.3
server02 30m IN A 192.168.0.4

webmail 24h IN CNAME server01
extranet 24h IN CNAME server02
ftp 24h IN CNAME server02

</code></pre>