Update

ssh

It turns out that the "ssh" option to the kernel causes the ssh daemon to start before files are "restored" from "backup", leading to new host key generation on every reboot. Yuck. So I've removed the "ssh" option from the kernel and added "/etc/init.d/ssh start" to /opt/bootlocal.sh

network config

The network configuration scripts must occupy /opt/${device}.sh and look like

#/bin/bash
pkill pump
pump -h us-gso-lxrouter-0 -i eth0

and

#!/bin/bash
pkill pump
ifconfig eth1 10.1.2.3 netmask 255.255.0.0 broadcast 10.1.255.255 up

Damn Small Linux (DSL) Frugal install under QEMU/KVM

intent

I want a virtual router within QEMU/KVM where I control iptables so I can build systems on simulated subnets.

libvirtd config

• 1 2Gbyte hard drive (default DSL install doesn't recognize SCSI drive)
• from within DSL, cfdisk to create 3 partitions: hda1 100Mbyte type Linux bootable, hda2 128Mbyte type Linux  swap, hda3 the remainder type Linux
• 256Mbyte memory
• one cpu
• Install from ISO image

Frugal install

• specified install onto hda1
• specified backup (also used for /home and other) as hda3

edits to Grub menu.lst

• mount /mnt/hda1 and edit /mnt/hda1/boot/grub/menu.lst
• turned on dma - without that, significant (virtual) disk access pegged the CPU
• changed init runlevel target to 2 to avoid GUI startup
• final grub stanza looked like

  title Optimized
  kernel /boot/linux24 2 root=/dev/hda1 quiet vga=normal noacpi noapm dma noscsi toram ssh fuse mydsl=hda3 restore=hda3 frugal host=vrouter
  initrd /boot/minirt24.gz 

Changing /etc/inittab

By default, DSL in run level 2 puts a root shell prompt on the console tty[1234] but that makes me queasy, especially since this CentOS 6.4 system running QEMU/KVM puts no password on the VNC console access to the running virtual machine.  So I did the following

• Added "etc/inittab" to /opt/.filetool.lst
• In /etc/inittab file, replaced the instances of /bin/bash -login with /sbin/getty 38400 tty1 (appropriate tty used for each the four consoles)
• In /opt/bootlocal.sh, did

  /sbin/telinit q
  

iptables

• I used MyDSL to install iptables.dsl
• In /opt/bootlocal.sh start iptables, which will be essential to simulating various subnets.

  /etc/init.d/iptables start
  

• In /opt/.filetool.lst specify persistence of /var/lib/iptables

ssh

Put "etc/ssh" into /opt/.filetool.lst

Passwords

To persistently change the root and dsl account passwords, I used "passwd" then specified "etc/shadow" in /opt/.filetool.lst

Persistence

The command line reboot and shutdown -r commands do not save persistent data; you need to explicitly run /usr/sbin/filetool.sh backup before rebooting.

Networking

I have static configuration rather than the default dhcp for eth1, eth2, .... To that end I add "etc/sysconfig/network-scripts" to /opt/.filetool.lst