Before you can deploy a cloud, you first need a blue sky. That's where aoi
(pronounced "ah-oh-E") comes in. (aoi is the Japanese word for "blue".)
aoi is a set of scripts that allow you to easily deploy Ubuntu cloud images
onto local virtual machines for test purposes only. This tool is optimized
to create consistent test environments, and should not be used for production
environments.
Containers can behave slightly differently than a fully virtualized
host. Since aoi is intended for software QA, the first step was to remove
the "are we in a container?" variable. Container support is in mind
for the near future.
aoi has the following features, which are interesting for creating
test environments:
When you initialize aoi, it uses rsync to download the latest Ubuntu
cloud images, then verifies them and creates a hash-based link.
The cloud images are used as a base image for any new virtual machine launched, so virtual machines are fast to create and space-efficient.
When you launch an image with aoi, instances with the same name will always
get the same MAC address. This makes it easy to identify which nodes on the
network belong to which host, which means it's much easier to create scripts
which must work with MAC addresses.
As a side benefit, DHCP servers will provide consistent IP addresses to test machines as well. (No more running out of IP addresses since you tore down and rebuilt your test environment too much!)
When you initialize aoi, it creates SSH host keys that will be used for
every virtual machine. That makes it easier to use ssh, since the host key
won't change whenever a test environment is torn down and rebuilt.
After aoi is initialized, no root access is required to launch new
virtual machines. Your user must belong to the libvirtd and kvm groups
(and this will be done for you automatically upon aoi init).
By default, aoi simply uses the virbr0 bridge that is created when
libvirt is installed. (A second private network is created for testing.)
There is no dependency on network configuration.
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.
You should put aoi in your $PATH. For example:
git clone https://github.com/pontillo/aoi.git
cd aoi
export PATH="$(pwd):$PATH"
Running aoi init 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 lot out
and run the script again.
Example usage (from scratch):
aoi init
aoi launch <release-codename> <instance-name>
By default, the release-codename argument can be trusty or xenial, but
cloud images for other releases can by synchronized manually.
For example, to create a virtual machine named foo running xenial, you
could use:
aoi launch xenial foo
Then you can SSH to the instance (even without knowing its IP address)
using the aoi-ssh script:
aoi-ssh foo
After you've finished with the virutal machine, you can easily delete it (along with all its data):
aoi-delete foo
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.
By default, a test network (called testnet) will be created by the init
script, using the 172.16.99.0/24 subnet (this cannot yet be configured
without changing the script).
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 aoi-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.
A wrapper that allows SSH without checking the key of the remote system. This is used despite the "consistent SSH keys" approach for easier scripting (but you'll appreciate the consistent keys if you need to manually poke at a test environment).
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
aoi-get-mac script), then uses aoi-untrusted-ssh 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. Use with
caution, as this can cause virtual machines (and containers) attached to the
bridge to be disconnected until restarted.
Wrapper to use dig to query the dnsmasq running on virbr0.