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Re: Questions while I read: what to do about hostnames?


On 21-Dec-16 20:23, Samuel D Matzek wrote:
OpenPower systems and AIX deployments traditionally like static IPs and VMs are normally treated as "pets" vs the "cattle" mentality that you normally have in the cloud.
nods. AIX/UNIX places I have visited tend more towards static setups - one aspect of being a pet. But this is not a matter of OS. This is a condition, from what I have seen, that has "systems management", in particular "network systems management" who consider themselves owners and controllers of IP addresses. IP addresses are not configured into DNS until a request is made for an address (the network choose the IP address based on a number of parameters - and the requested hostname is passed as part of the request.
For Linux and AIX on OpenPower systems we needed to meet the market where they were and the dhcp or statically assigned hostname choice didn't sit well as it required the OpenStack instance name to match the short hostname and match the DNS record. To help with this we added another config module to the AIX cloud-init port (and it's in our cloud-init repackaging for Linux dists). The config module allows you the option of having the VM do a DNS reverse lookup on is statically assigned IP to get its hostname from the DNS and then set it appropriately.
So, I think we are quite close - the xxxx could be DNSLookup, or "reverse" to specify that the "hostname to set to is to come from an IP address specified in "source". Thinking outloud - adding distro dependent modules is always a possibility. I am just wondering if we can come to a more unified grammer rather than tacking a new module in to, effectively, bypass the "current" grammar. In any case, it is an activity I did not have a name for. So, if you could choose - would you go for a new "spot on a cow" (adjective in an existing or new grammar) or do you think introducing a new (pet-)module is better?

set_hostname: dhcp|source|xxxx - just think there may be more choices than dhcp or "datasource"