Guide: OpenStack Python SDK – Basic Usage

This guide provides a quick introduction to managing your bwCloud-OS resources using the OpenStack Python SDK. It covers the most common operations for compute, storage, and networking.

In the following, we demonstrate the routines using an interactive Python shell. In practice, these routines are typically used within Python scripts.

Note: In the interactive Python shell, multi-line blocks (e.g., loops or function definitions) are executed after pressing Enter twice.

Prerequisites

Install the OpenStack SDK, e.g. for Ubuntu:

sudo apt install python3-openstacksdk 

Alternatively, you can install it via pip (preferably inside a virtual environment):

python3 -m venv openstacksdk_venv
source openstacksdk_venv/bin/activate
pip install openstacksdk

Authentication

You can either:

• source an OpenRC file, or
• use a clouds.yaml file

For details, see the section Create an application credential.

In the following, we use the clouds.yaml method.

Basic Connection

Create a connection in Python:

import openstack
conn = openstack.connect(cloud="openstack")

Compute

Images

List available images:

for image in conn.image.images():
    print(image.name, image.id)

Upload a new image:

import os

image_path = "/path/to/images/ubuntu-24.04-server-cloudimg-amd64.img"
if not os.path.isfile(image_path):
    raise FileNotFoundError(f"Image file not found: {image_path}")

with open(image_path, "rb") as img:
    image = conn.image.upload_image(
        name="ubuntu-24.04",
        data=img,
        disk_format="qcow2",
        container_format="bare"
    )

print("Image ID:", image.id)

Show image details:

image = conn.image.get_image("<IMAGE_ID>")
print(image)

Delete an image:

conn.image.delete_image("<IMAGE_ID>")

Key Pairs (SSH Access)

Create a key pair:

keypair = conn.compute.create_keypair(name="myKey")
with open("myKey.pem", "w") as f:
    f.write(keypair.private_key)

Set correct permissions (outside Python shell):

chmod 600 myKey.pem

List key pairs:

for kp in conn.compute.keypairs():
    print(kp.name)

Delete a key pair:

conn.compute.delete_keypair("myKey")

Instances

List instances:

for server in conn.compute.servers():
    print(server.name, server.status)

Create an instance (ensure that the specified image, flavor, network, and key pair exist):

image = conn.compute.find_image("ubuntu-24.04")
flavor = conn.compute.find_flavor("p1.tiny")
network = conn.network.find_network("myNet")
server = conn.compute.create_server(
    name="myVM",
    image_id=image.id,
    flavor_id=flavor.id,
    networks=[{"uuid": network.id}],
    key_name="myKey"
)
server = conn.compute.wait_for_server(server)
print("Created:", server.name)

Show details of an instance:

server = conn.compute.find_server("myVM")
if server is None:
    raise ValueError("Server 'myVM' not found")

server = conn.compute.get_server(server.id)
print(server)

Delete an instance:

server = conn.compute.find_server("myVM")
conn.compute.delete_server(server.id)

Storage

Volumes

List volumes:

for vol in conn.block_storage.volumes():
    print(vol.name, vol.size)

Create a volume (size in GB):

volume = conn.block_storage.create_volume(
    name="myVolume",
    size=10
)

Delete a volume:

volume = conn.block_storage.find_volume("myVolume")
conn.block_storage.delete_volume(volume.id)

Volume Management for Instances

Attach a volume to an instance:

server = conn.compute.find_server("myVM")
volume = conn.block_storage.find_volume("myVolume")
conn.compute.create_volume_attachment(
    server,
    volumeId=volume.id
)

Detach a volume from an instance:

attachments = conn.compute.volume_attachments(server)
for att in attachments:
    if att.volume_id == volume.id:
        conn.compute.delete_volume_attachment(att.id, server)

Networking

Networks

List networks:

for net in conn.network.networks():
    print(net.name)

Create a network:

network = conn.network.create_network(name="myNet")

Delete a network:

network = conn.network.find_network("myNet")
conn.network.delete_network(network.id)

Subnets, Routers

Create a subnet:

network = conn.network.create_network(name="myNet")

subnet = conn.network.create_subnet(
    name="mySubnet",
    network_id=network.id,
    ip_version=4,
    cidr="192.168.1.0/24"
)

Create a router:

router = conn.network.create_router(name="myRouter")

Attach a subnet to a router:

conn.network.add_interface_to_router(
    router,
    subnet_id=subnet.id
)

Set external gateway of a router:

external_net = conn.network.find_network("provider_default_net")

conn.network.update_router(
    router,
    external_gateway_info={"network_id": external_net.id}
)

Detach a subnet from a router:

conn.network.remove_interface_from_router(
    router,
    subnet_id=subnet.id
)

Delete a router:

conn.network.delete_router(router.id)

Delete a subnet (after detaching all ports from the subnet):

conn.network.delete_subnet(subnet.id)

Floating IPs

Create a floating IP (requires access to the provider network):

network = conn.network.find_network("provider_default_net")
fip = conn.network.create_ip(floating_network_id=network.id)
print(fip.floating_ip_address)

List floating IPs:

for fip in conn.network.ips():
    print(fip.floating_ip_address, fip.status, fip.port_id)

Associate a floating IP with an instance:

server = conn.compute.find_server("myVM")
port = list(conn.network.ports(device_id=server.id))[0]
conn.network.update_ip(fip, port_id=port.id)

Disassociate a floating IP:

 conn.network.update_ip(fip, port_id=None)

Release (delete) a floating IP:

conn.network.delete_ip(fip.id)

Security Groups

List security groups:

for sg in conn.network.security_groups():
    print(sg.name)

Create a security group:

sg = conn.network.create_security_group(name="mySecGroup")

Add a rule to a security group (e.g., HTTP access via port 80):

conn.network.create_security_group_rule(
    security_group_id=sg.id,
    direction="ingress",
    protocol="tcp",
    port_range_min=80,
    port_range_max=80,
    ethertype="IPv4"
)

Assign security group to an instance:

server = conn.compute.find_server("myVM")
conn.compute.add_security_group_to_server(server, sg.name)

Remove a security group from an instance:

conn.compute.remove_security_group_from_server(server, sg.name)

Delete a security group:

conn.network.delete_security_group(sg.id)