Q:

setting archlinux hostname (Amazon EC2)

Setting the hostname on an archlinux machine is relatively trivial according to this - https://wiki.archlinux.org/index.php/HOSTNAME#Set_the_hostname
So on my /etc/rc.conf, I have
LOCALE="en_US.UTF-8" 
TIMEZONE="UTC" 
MOD_AUTOLOAD="no" 
USECOLOR="yes" 
USELVM="no" 
DAEMONS=(syslog-ng sshd crond ec2 httpd) 
HOSTNAME="archlinux" 

And corresponding on my /etc/hosts, I have
127.0.0.1       archlinux.domain.org localhost.localdomain      localhost   archlinux

Following the docs to the tee.
But unfortunately, restarting httpd fails with the error in the error_log:
[Tue Sep 06 04:26:06 2011] [alert] (EAI 2)Name or service not known: mod_unique_id: unable to find IPv4 address of "ip-10-130-57-114" 

Configuration Failed
And yes, I am aware that from https://wiki.archlinux.org/index.php/Apache#Apache - it is possible to solve this problem by commenting 
LoadModule unique_id_module        modules/mod_unique_id.so

But I would much prefer to solve this problem by keeping this module loaded and resolving it by making sure that I have set my hostname correctly in /etc/hosts instead.

A:

It looks like Apache is using "ip-10-130-57-114" hostname instead of "archlinux". Have you tried adding this entry into your /etc/hosts file?

10.130.57.114 ip-10-130-57-114

* I am guessing 10.130.57.114 is the internal host ip address of you instance.

