KVM Guest Operating System
The KVM Guest is a sparse installation.
KVM Guest Template
Install Debian
Define your disk layout, then go ahead and install Debian. Make sure this is an installation with a minimum of packages. Once Debian has been installed, leave the template alone. On a fresh minimal installation, not much diskspace is used.
Filesystem Size Used Avail Use% Mounted on /dev/mapper/vg_os-root 1,9G 791M 954M 46% / /dev/vda1 243M 53M 162M 25% /boot
KVM Guest Clone
Clone Your Template
Start by cloning your template.
Configure the New Guest
Root Password
Reset your root passwd.
passwd
Hostname
Your new system will need a new hostname.
- /etc/hostname
- /etc/hosts
sed -i 's/stretch-template/clone/g' /etc/hosts sed -i 's/stretch-template/clone/g' /etc/hostname
Unique sshd keys
Make sure your clone does indeed have unique ssh keys. This is a really important step when cloning. Consider all your clones had the same ssh keys, that would really be a mess.
rm /etc/ssh/ssh_host_* dpkg-reconfigure openssh-server service sshd restart
Update
Make sure downloaded .deb files are removed after they have been installed.
echo "APT::Keep-Downloaded-Packages \"false\";" > /etc/apt/apt.conf.d/01keep-debs
Since the template can be quite old, you might as well update the new system.
apt-get update apt-get upgrade