Oct 132019
 

Over the years, I have learned not to rely on hostnames for important services. Hosts go away, new ones come in. I want to rely on, what I refer to as, service names.

For example, instead of relying on a hostname for my ntp server, I have:

$ host time
time.int.unixathome.org has address 10.55.0.1

This hostname, or service name, appears in /etc/ntp.conf on every physical host in my network.

time.int.unixathome.org is not a host, that’s just a DNS entry pointing at the IP address on a host:

$ host 10.55.0.1
http://1.0.55.10.in-addr.arpa domain name pointer http://bast.int.unixathome.org.

Why?

If I rename bast, or replace it, the time DNS entry is just adjusted. I don’t have to change /etc/ntp.conf on every host. Doing less work is always a good thing. Yes, it is more work now, but you are avoiding future work.

How much more work is it? You need to add one more DNS entry. That’s not much work at all.

This issue came to mind as I thought about retiring the R710 (hostname r710-01) and replacing it with the R720 (r720-01).

Ideally, all I need to do is change some Bacula backup jobs, some monitoring, and some
LibreNMS entries.

We shall see.

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