How to launch a DreamCompute server with Ansible

Ansible is a configuration management tool with built in OpenStack support. Using Ansible, you can deploy and manage instances on DreamCompute. This tutorial explains how to install Ansible and use it to launch an instance on DreamCompute.

This tutorial uses Ubuntu 22.04 as the host to run Ansible playbooks. First, install a few packages using the following command.

[user@localhost]$ sudo apt-get install -y ansible python2.7 python-virtualenv python-pip

Ansible depends on 'shade' which is a Python client library for interacting with OpenStack. Create a virtual environment and use pip to install 'shade'.

[user@localhost]$ virtualenv venv -p /usr/bin/python
[user@localhost]$ source venv/bin/activate
(venv)user@localhost]$ pip install shade

Now you have 'shade' installed and are ready to start writing Ansible playbooks.

Playbooks are Ansible’s configuration, deployment, and orchestration language. At a basic level, playbooks can be used to manage configurations and deployments to remote machines. Playbooks are designed to be human-readable and are developed in a basic text language.

Create a file named launch-server.yaml and enter the following lines into it.

1. The first part of your playbook is a list of hosts that your playbook will run on. In this case there is one, localhost.

   # hosts the playbook runs on
   - hosts: localhost

2. Since 'shade' has been installed in the virtualenv, you must tell ansible to use this virtualenv. Move to the next line, indent 2 spaces, then add these lines.

   # hosts the playbook runs on
   - hosts: localhost
     vars:
       ansible_python_interpreter: "/usr/bin/env python"

3. Define a list of tasks to perform in this playbook. Move to the next line, indent 2 spaces, then add these lines.

   # hosts the playbook runs on
   - hosts: localhost
     vars:
       ansible_python_interpreter: "/usr/bin/env python"
   
     # List of tasks
     tasks:
     - name: launch an Ubuntu server

4. Use the os_server module to create an OpenStack instance. Move to the next line, indent 2 spaces, then add this line.

   # hosts the playbook runs on
   - hosts: localhost
     vars:
       ansible_python_interpreter: "/usr/bin/env python"
   
     # List of tasks
     tasks:
     - name: launch an Ubuntu server
   
       # Define a server
       os_server:

5. Add DreamCompute authentication so an instance can be created. In the following example, substitute the following:
   • {username} — your DreamCompute dashboard username.
   • {password} — your DreamCompute dashboard password.
   • {project} — your DreamCompute project. This can be found in the dashboard on the top left.

     

   Move to the next line, indent 2 spaces, then add these lines.

   # hosts the playbook runs on
   - hosts: localhost
     vars:
       ansible_python_interpreter: "/usr/bin/env python"
   
     # List of tasks
     tasks:
     - name: launch an Ubuntu server
   
       # Define a server
       os_server:
   
       # Cloud authentication information
       auth: 
         auth_url: https://iad2.dream.io:5000 
         username: {username} 
         password: {password} 
         project_name: {project}

6. Finally, define what the instance should look like.

   # hosts the playbook runs on
   - hosts: localhost
     vars:
       ansible_python_interpreter: "/usr/bin/env python"
   
     # List of tasks
     tasks:
     - name: launch an Ubuntu server
   
       # Define a server
       os_server:
   
         # Cloud authentication information
         auth:
           auth_url: https://iad2.dream.io:5000
           username: {username} 
           password: {password} 
           project_name: {project}
   
         # VM details
         state: present
         name: ansible-vm1
         image: Ubuntu-22.04
         key_name: myKey
         flavor: 50
         network: public
         wait: yes
   

Breakdown the last few lines

The Ansible playbook can be run with the following command:

[user@localhost]$ ansible-playbook launch-server.yaml

You should see output like

PLAY [localhost]
***************************************************************************

TASK [Gathering Facts]
***************************************************************************
ok: [localhost]

TASK [launch an Ubuntu server]
***************************************************************************
changed: [localhost]

PLAY RECAP
***************************************************************************
localhost                  : ok=2    changed=1    unreachable=0    failed=0

Now if you check the DreamCompute dashboard you will see the new instance named “ansible-vm1”