Openstack Python SDK tutorial using Flask
- You have an existing Openstack installation up and running.
- You have already downloaded the openrc.sh file from Horizon for your project. Sample demo-openrc.sh file downloaded from Horizon for a Devstack install is included.
- The OS_AUTH_URL mentioned in the openrc.sh file is accessible from the environment or terminal used to run this Flask app. If the OS_AUTH_URL IP is a private IP, you need to run the Flask app from the same VM (for Devstack installations) or Network Openstack is running on. Updating this IP to the assigned public IP of the Devstack VM may not work as the Openstack Endpoints for Compute etc. will still be available only on the Private IP.
$ git clone https://github.com/mayankkapoor/openstack-python-sdk-tutorial.git
$ cd openstack-python-sdk-tutorial
$ python3 -m venv venv # Create a virtualenv under directory venv
$ . venv/bin/activate # Activate virtualenv
(venv)$ pip install -r requirements.txt # Install necessary dependencies for the Flask app
This repo has a file flaskr/app.py that runs a flask server on port 8080. It assumes the appropriate Openstack environment variables are already set in order for it to talk to Openstack. Therefore, download your openrc.sh file from your project in Horizon and source it. Assuming the openrc file is called demo-openrc.sh:
(venv)$ source demo-openrc.sh
Please enter your OpenStack Password for project demo as user demo:
<Enter your openstack password for user demo>
(venv)$ python flaskr/app.py
* Serving Flask app "app" (lazy loading)
* Environment: production
WARNING: This is a development server. Do not use it in a production deployment.
Use a production WSGI server instead.
* Debug mode: on
* Running on http://0.0.0.0:8080/ (Press CTRL+C to quit)
* Restarting with stat
* Debugger is active!
* Debugger PIN: 302-433-515
Open http://localhost:8080/ in your browser, it should print "Hello from Flask!".
Open http://localhost:8080/list in your browser. This will print a list of current resources in your openstack on the terminal where you started the Flask app.
...
* Debugger PIN: 283-629-770
49.36.1.41 - - [25/May/2019 14:22:33] "GET / HTTP/1.1" 200 -
conn: <openstack.connection.Connection object at 0x7fc49a235198>
[{'access_ipv4': '',
'access_ipv6': '',
'addresses': {'private': [{'OS-EXT-IPS-MAC:mac_addr': 'fa:16:3e:1a:d3:63',
'OS-EXT-IPS:type': 'fixed',
'addr': '10.0.0.19',
'version': 4},
{'OS-EXT-IPS-MAC:mac_addr': 'fa:16:3e:1a:d3:63',
'OS-EXT-IPS:type': 'fixed',
'addr': 'fd0d:1d87:b84d:0:f816:3eff:fe1a:d363',
'version': 6}]},
'admin_password': None,
'attached_volumes': [{'id': 'cefdec32-abbd-4ad6-bd52-3b457d1e42be'}],
'availability_zone': 'nova',
'block_device_mapping': None,
'compute_host': 'ip-172-31-7-51',
'config_drive': '',
'created_at': '2019-05-25T11:06:31Z',
'description': None,
'disk_config': 'AUTO',
'flavor': {'id': '84',
'links': [{'href': 'http://172.31.7.51/compute/flavors/84',
'rel': 'bookmark'}]},
'flavor_id': None,
'id': '0649ea9e-b4da-4d1e-a82c-7bfa33a0470d',
'instance_name': 'instance-00000001',
'is_locked': None,
'kernel_id': None,
'key_name': 'mayank-public-key',
'name': 'first-instance',
'networks': None,
...
Congratulations, you've connected to Openstack using the Openstack SDK. Now, let's try to create a virtual machine (server) using the Openstack SDK.
The app.py has a function "create_server" which takes in GET parameters from the browser to create a volume first, then a server with the created volume attached.
Type http://localhost:8080/create_server?server_name=server1&volume_size=2 into the browser. This will create an instance with volume of size 2 GiB and name "server1".
Note: Don't enter spaces in the browser address bar as they will not be understood by the browser and the create_server function will not work.