Spawning your first OpenStack instance with Ansible
by Juan Antonio Osorio Robles
Great, so you got access to an OpenStack cloud, got your credentials ready, and even spawned a test instance through Horizon. Life is great! You’re proud that you’re finally getting the hang out of this OpenStack thingy.
But… doing this through horizon is slow…
Then you figure out that doing it through the CLI is actually kinda slow as well.
Do I have to do all those clicks, or all those commands every time? Maybe I’ll just hook everything up in a bash script and hope I never have to extend it.
or… maybe I can just use Ansible!
The OpenStack Ansible modules are cool
Staying true to their statement of aiming to automate thing in a simple manner, the OpenStack ansible modules are already quite simple and usable.
In case you’re wondering where they are, here’s the list of OpenStack modules.
But before you dive into writing your playbooks just yet, lets do one thing first.
Writing your clouds.yaml
Remember when you where using the OpenStack CLI? You needed to source a file (maybe called openrc or overcloudrc) that contains your user credentials, as well as the authentication URL and some other values that you might or might not be very acquainted with.
While you could still use these environment variables to run your ansible playbooks, you could also specify them in a file called clouds.yaml.
clouds.yaml allows you to specify several parameters to access your cloud provider, such as the authentication credentials, the region to use, as well as logging configurations and some other OpenStack client-specific configurations.
It can be very useful if you have access to several OpenStack providers, since all you’ll need to do is specify the name of the provider, and it’ll immediately use the credentials you set on its respective section.
A very simple clouds.yaml will look as follows:
This defines a cloud called mariachicloud that you can reference from both ansible and your OpenStack CLI. So, if you want to take it into use from the OpenStack CLI, you could do the following:
This will list the instances spawned in your project on your mariachicloud
account. Note that the important thing is to specify your cloud with the
--os-cloud parameter. When doing openstack commands, there are three places
that the client will look for the clouds.yaml file:
- The current working directory
A sample playbook
Here’s a simple playbook that shows how to spawn an instance in the “mariachicloud” cloud provider
This playbook makes the following assumptions:
We already have an external network for our project, in our case it’s called test-external-network.
We have already created a keypair with which we can access the instance. In our case it’s called mariachi-pub-key.
there is an image uploaded already that’s called CentOS-7-x86_64-GenericCloud.
There is a flavor created already that’s called m1.small.
With this in mind, the playbook itself will create:
- A network called test-network.
- A subnet in that network, called test-subnet.
- A router that’s connected to the subnet and the external network. The router’s name is test-router.
- A security group called test-security-group.
- Two rules for the aforementioned security group.
- One rules allows all ping traffic to come into the instance (the default direction for the rule is ingress).
- Another rule that allows SSH traffic into the instance.
- One instance called test-instance. This instance is using the
aforementioned security group, and is also connected to our test-network.
Besides this, we set the
auto_ipparameter, which automatically assigns a floating IP to the instance, which we can use to access the instance.
The last two tasks in our playbook will give us the floating IP address that we can use to access our instance.