I want to get away from using hostnames as identifiers within applications. Following the "servers are cattle, not pets" concept, binding server interaction to hostnames makes dynamic changes more difficult. Where ISPConfig configurations and related applications ask for 'hostname', I prefer to reference resources by the service they perform rather than by name, and use DNS to redirect to whatever server is performing a required service. So, it doesn't matter if host1 or host2 or host3 is running DNS services, the server should be referred to as dns1 internally and then any system running as the primary DNS should provide the service. Is that a common practice with those of you who manage larger and more dynamic environments? All ISPConfig docs refer to 'hostname' and 'server name' but I think more advanced users would recognize this as 'DNS A record to the required server'. I understand the concept of "service discovery" is increasingly common for cloud servers. Is ISPConfig designed to operate in a "service registry" configuration, or is it more oriented toward actual hostnames? Am I moving in the right direction or am I missing something? Thanks!
The hostname does not matter. It just has to exist, as other servers might refuse to talk to your system if the hostname it presents can not be resolved in DNS. This is relevant mainly for Email. When it comes to ISPConfig, the hostname does not matter at all. Hostnames are mostly chosen for the convenience of the admin so he can better find and recognize a system. So if you call your system this-is-not-mail-server.yourdomain.tld and run email services on it or if you name your system named ns1.yourdomain.tld and run web services, or if you just use numbers like s13815237.yourdomain.tld, this all does not matter for the provided services. Services on server systems work like this: When traffic arrives on a given port of a server, and the server runs a service on that port, then this service can answer the requests it receives. Does the hostname matter for this? no. Does it matter if ISPConfig is service-oriented or not for this: no. The only thing that matters is that a client knows where to connect, and this is done by setting DNS records plus, you can also use things like load balancers in larger setups to route incoming traffic that matches certain criteria.
