This repository contains a set of scripts that allow you to easily deploy Ubuntu cloud images onto local virtual machines.
This set of scripts was developed on Ubuntu 16.04 LTS (Xenial). It is not
guaranteed to work on any other platform. (At least one script requires
python3 at the time of this writing.)
Assuming your platform is supported, the init script will take care
of setting up the dependencies. See the Installation Notes section
for more details.
Your ~/.ssh/authorized_keys file MUST be populated with whatever keys
you wish to use with the virtual machines. The cloud images do not have
a default username and password.
An init script is supplied, which will take care of the tasks needed to get
started. If your user is not already in the kvm and libvirtd groups, you
may need to run the script twice.
Example usage (from scratch):
./init
./create <vm-hostname> [distro]
For example, to create a virtual machine named foo running xenial, you
could use:
./create foo xenial
As part of the init script, the sync script runs. While sync must only
be run once, if it is run subsequently, it will fetch the latest cloud image,
but leave the old image in place (based on its sha256 hash) in case other
images were built upon it.
After you've finished with the virutal machine, you can easily delete it (along with all its data):
./delete <vm-hostname>
By default, a test network (called testnet) will be created by the init
script. Also, the domain name for the default network will be set to .vm.
This means you can look up the IP addresses for your machines in the
.vm domain by querying the dnsmasq running on the default network, which
is at 192.168.122.1 by default.
If you want your virutual machines to be resolved in Ubuntu, (assuming you
are running NetworkManager), you can create
/etc/NetworkManager/dnsmasq.d/libvirt.conf as follows:
server=/vm/192.168.122.1
This assumes that your default network is configured to with an IP address
of 192.168.122.1.
Note: This currently causes issues whereby DNS queries can become extremely slow. See this question on Server Fault for more information.
This repository also contains a few helper scripts, which can be helpful
(assuming, as the scripts do, that you are using virbr0).
Returns the IP address for the specified hostname, based on its mac (returned
from get-mac), by looking it up in the ARP cache.
Returns the IP address for the specified hostname, based on its mac (returned
from get-mac), by looking it up in the DHCP lease table.
Utility to return a consistent MAC address given the specified hostname. This
is useful so that when tearing down and recreating virtual machines with the
same name, consistent MAC addresses are used, which should cause dnsmasq to
hand out consistent IP addresses as well.
Gets the name of a virsh bridge, based on the virsh network name.
The ussh utility stands for Untrusted SSH. It is a wrapper that allows
SSH without checking the key of the remote system.
The vssh utility stands for VM SSH. It is a wrapper which attempts to
look up the IP address of the virtual machine (based on the ARP cache and the
expected hostname-based MAC from the get_mac script), then runs ussh to open a session.
Utility script to clear out dnsmasq's lease database for the default network
(most likely virbr0). Also restarts the libvirt-bin service.
Utility to return a consistent MAC address given the specified hostname. This
is useful so that when tearing down and recreating virtual machines with the
same name, consistent MAC addresses are used, which should cause dnsmasq to
hand out consistent IP addresses as well.
Wrapper to use dig to query the dnsmasq running on virbr0.
First, you'll need to ensure the following packages are installed:
sudo apt install libvirt-bin qemu-kvm virtinst uuid
Your user must be in the libvirtd and kvm groups for these scripts to
work:
sudo usermod -a -G libvirtd,kvm $USER
If you get errors regarding permission to access the backing images, you may need to set the AppArmor profile for libvirt to complain mode:
$ sudo apt-get install apparmor-profiles apparmor-utils
$ sudo aa-complain /usr/lib/libvirt/virt-aa-helper