A hostname is not a unique key on its own though. A hostname is only unique within a domain, so you really need a 'composite key' consisting of hostname and domainname together to get a unique value. So, using the database theory analogy, one cannot designate a hostname as a primary/unique key in the table of hosts.
-Jason Martin > -----Original Message----- > From: > [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] > org] On Behalf Of David Masterson > Sent: Monday, November 07, 2005 11:08 AM > To: Mark Burgess > Cc: help-cfengine@gnu.org > Subject: RE: editfiles methodology question > > > Mark Burgess wrote: > > On Sun, 2005-11-06 at 14:47 -0800, David Masterson wrote: > >> Mark Burgess wrote: > >>>> Regarding short_hostname, on my system '/bin/hostname' > returns the > >>>> FQDN. If I try using $(host), I just get the FQDN. Is > that normal? > >>>> That's why I'm using my own variable. > >>> > >>> This is normal if you have fully qualified names returned by your > >>> hostname lookup, which is not something I recommend. > >> > >> There is a discussion going on here about the merits of FQDN vs. > >> simple hostname. Would you care to elaborate on your > reasons for not > >> recommending FQDN in hostname lookup? > >> > > > > Just as a matter of principle that you don't mix different kinds of > > information. It is the principle of "normalization" or > "normal forms" > > in database theory. The hostname is one item of information, the > > domain name is another. You should be able to change and > manage them > > independently of one another. If you always store the > domain name as > > the host identity then you have made it very hard to separate those > > two pieces of information, and have made relative information > > absolute. It is also possible to record information that is > incorrect > > and does not match information in DNS this way. Again. > normalization > > says this is a bad idea. > > Hmm. I'm in the simple hostname camp, but IT is more in the > FQDN camp. I need to bring your explanation down a little -- > can you give an example of where FQDN caused problems? Is it > just an esoteric "ease of use" issue or does it have consequences? > > Consider establishing a company policy where all NIS servers > are "nis[0-9]". At the company level, these systems have an > FQDN of "nis[0-9].x.com". However, group NIS servers have an > FQDN of "nis[0-9].y.x.com" (where y is the group). > Obviously, you could have multiple "nis1" hosts in your > organization. Is this a good company policy? > > -- > David Masterson > VMware, Inc. > Palo Alto, CA > > > _______________________________________________ > Help-cfengine mailing list > Help-cfengine@gnu.org > http://lists.gnu.org/mailman/listinfo/help-> cfengine > _______________________________________________ Help-cfengine mailing list Help-cfengine@gnu.org http://lists.gnu.org/mailman/listinfo/help-cfengine
