python-novaclient

python bindings and CLI for Nova

Joe Gordon

About Me

OpenStack Architecture

Nova

Architecture Diagram

Nova REST API

API for users to manage

  • instances
  • ip addresses
  • keypairs
  • networks
  • snapshots
  • admin APIs

python-novaclient

github.com/openstack/python-novaclient


pip install -U python-novaclient

CLI

Python Library

Our Development Environment

ca.enocloud.com

Booting a VM

  • CLI
  • Python Library

CLI




$ nova --debug boot --flavor=m1.tiny --image=cirros-0.3.1-x86_64-uec\
--key-name=mykey myinstance

Python Library


import os
import time
from novaclient.v1_1 import client

def get_nova_creds():
    d = {}
    d['username'] = os.environ['OS_USERNAME']
    d['api_key'] = os.environ['OS_PASSWORD']
    d['auth_url'] = os.environ['OS_AUTH_URL']
    d['project_id'] = os.environ['OS_TENANT_NAME']
    return d

nova = client.Client(**get_nova_creds())
if not nova.keypairs.findall(name="mykey"):
    with open(os.path.expanduser('~/.ssh/id_rsa.pub')) as fpubkey:
        nova.keypairs.create(name="mykey", public_key=fpubkey.read())
image = nova.images.find(name="cirros")
flavor = nova.flavors.find(name="m1.tiny")
instance = nova.servers.create(name="test", image=image, flavor=flavor, key_name="mykey")

# Poll at 5 second intervals, until the status is no longer 'BUILD'
status = instance.status
while status == 'BUILD':
    time.sleep(5)
    # Retrieve the instance again so the status field updates
    instance = nova.servers.get(instance.id)
    status = instance.status
print "status: %s" % status

Anatomy of nova boot

REST API calls

Simplified


$ nova --debug boot --flavor=m1.tiny --image=cirros-0.3.1-x86_64-uec\
--key-name=mykey myinstance
          

POST http://$KEYSTONE_IP:5000/v2.0/tokens
GET  http://$NOVA_IP:8774/v2/$UUID/images/detail
GET  http://$NOVA_IP:8774/v2/$UUID/flavors/detail
POST http://$NOVA_IP:8774/v2/$UUID/servers

How to use the python-novaclient

Before getting started, source your credentials


OS_AUTH_URL=http://$KEYSTONE_IP:5000/v2.0
OS_PASSWORD=password
OS_TENANT_NAME=demo
OS_USERNAME=demo

Initialize a nova client


#!/usr/bin/env python
import os

from novaclient.v1_1 import client

def get_nova_creds():
    d = {}
    d['username'] = os.environ['OS_USERNAME']
    d['api_key'] = os.environ['OS_PASSWORD']
    d['auth_url'] = os.environ['OS_AUTH_URL']
    d['project_id'] = os.environ['OS_TENANT_NAME']
    return d

nova = client.Client(**get_nova_creds())
#Get token (optional, happens on its own if not specified)
nova.authenticate()

Loading a key pair

To login into the instance with


if not nova.keypairs.findall(name="mykey"):
    with open(os.path.expanduser('~/.ssh/id_rsa.pub')) as fpubkey:
        nova.keypairs.create(name="mykey", public_key=fpubkey.read())
print nova.keypairs.list()

Finding the flavor


print nova.flavors.list()
          

flavor = nova.flavors.find(name="m1.tiny")

Finding the image


print nova.images.list()
          

flavor = nova.image.find(name="Exact-Image-name")

Booting an instance


image = nova.images.find(name="cirros")
flavor = nova.flavors.find(name="m1.tiny")
instance = nova.servers.create(name="test", image=image, flavor=flavor, key_name="mykey")

Tracking the instance


# Poll at 5 second intervals, until the status is no longer 'BUILD'
status = instance.status
while status == 'BUILD':
    time.sleep(5)
    # Retrieve the instance again so the status field updates
    instance = nova.servers.get(instance.id)
    status = instance.status
print "status: %s" % status
print "address: %s" % instance.addresses

Destroying the instance


instance.delete()

Resources

Thank You

Questions?

Slides can be found at jogo.github.io

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