Linux Networking Cookbook

4.14. Changing the Pyramid Router's Hostname

Problem

Pyramid is a nice name, but you really want to change it to something else. You tried editing /etc/hostname, but the name reset to Pyramid after reboot. Arg! How do you make it what you want?

Solution

The files listed in /etc/rw/ are mounted in a temporary writeable filesystem, and are copied from /etc/ro at boot. /etc/hostname is symlinked to /rw/etc/hostname:

	pyramid:~# ls -l /etc/hostname
	lrwxrwxrwx 1 root root 18 Oct 30 2006 /etc/hostname -> ../rw/etc/hostname

So, you can make /etc/hostname immutable (remove the symlink to /rw/etc/ hostname), or edit /ro/etc/hostname.

Discussion

The filesystem is set up this way to reduce writes, because Compact Flash supports a limited number of writes.

You can use find to see which files in /etc are symlinks:

	pyramid:~# find /etc -maxdepth 1 -type l -ls 6051 0 lrwxrwxrwx 1 root root 14 Oct 4 2006 /etc/mtab -> ../proc/ mounts 6052 0 lrwxrwxrwx 1 root root 21 Oct 4 2006 /etc/resolv.conf -> ../ rw/etc/resolv.conf 6079 0 lrwxrwxrwx 1 root root 30 Dec 31 2006 /etc/localtime -> /usr/ share/zoneinfo/US/Pacific 6081 0 lrwxrwxrwx 1 root root 18 Oct 4 2006 /etc/hostname -> ../rw/ etc/hostname 6156 0 lrwxrwxrwx 1 root root 15 Oct 4 2006 /etc/issue -> ../rw/ etc/issue 6195 0 lrwxrwxrwx 1 root root 17 Oct 4 2006 /etc/zebra -> ../usr/ local/etc/ 6227 0 lrwxrwxrwx 1 root root 16 Oct 4 2006 /etc/resolv -> ../rw/ etc/resolv 6426 0 lrwxrwxrwx 1 root root 19 Oct 4 2006 /etc/issue.net -> ../ rw/etc/issue.net 6427 ...