Launching instances

Before being able to run below commands, you will need a provider object (see this page).

Common launch data

Before launching an instance, you need to decide what image to launch as well as what type of instance. We will create those objects here. The specified image ID is a base Ubuntu image on AWS so feel free to change it as desired. For instance type, we’re going to let CloudBridge figure out what’s the appropriate name on a given provider for an instance with at least 2 CPUs and 4 GB RAM.

img = provider.compute.images.get('ami-759bc50a')  # Ubuntu 16.04 on AWS
vm_type = sorted([t for t in provider.compute.vm_types
                  if t.vcpus >= 2 and t.ram >= 4],
                  key=lambda x: x.vcpus*x.ram)[0]

In addition, CloudBridge instances must be launched into a private subnet. While it is possible to create complex network configurations as shown in the Private networking section, if you don’t particularly care in which subnet the instance is launched, CloudBridge provides a convenience function to quickly obtain a default subnet for use. We just need to supply a zone to use.

zone = provider.compute.regions.get(provider.region_name).zones[0]
subnet = provider.networking.subnets.get_or_create_default(zone)

When launching an instance, you can also specify several optional arguments such as the firewall (aka security group), a key pair, or instance user data. To allow you to connect to the launched instances, we will also supply those parameters (note that we’re making an assumption here these resources exist; if you don’t have those resources under your account, take a look at the Getting Started guide).

kp = provider.security.key_pairs.find(name='cloudbridge-intro')[0]
fw = provider.security.vm_firewalls.list()[0]

Launch an instance

Once we have all the desired pieces, we’ll use them to launch an instance:

inst = provider.compute.instances.create(
    name='cloudbridge-vpc', image=img, vm_type=vm_type,
    subnet=subnet, zone=zone, key_pair=kp, vm_firewalls=[fw])

Private networking

Private networking gives you control over the networking setup for your instance(s) and is considered the preferred method for launching instances. To launch an instance with an explicit private network, you can create a custom network and make sure it has internet connectivity. You can then launch into that subnet.

net = self.provider.networking.networks.create(
    name='my-network', cidr_block='10.0.0.0/16')
sn = net.create_subnet(name='my-subnet', cidr_block='10.0.0.0/28')
# make sure subnet has internet access
router = self.provider.networking.routers.create(network=net, name='my-router')
router.attach_subnet(sn)
gateway = net.gateways.get_or_create_inet_gateway()
router.attach_gateway(gateway)

inst = provider.compute.instances.create(
    name='cloudbridge-vpc', image=img, vm_type=vm_type,
    subnet=sn, zone=zone, key_pair=kp, vm_firewalls=[fw])

For more information on how to create and setup a private network, take a look at Networking.

Block device mapping

Optionally, you may want to provide a block device mapping at launch, specifying volume or ephemeral storage mappings for the instance. While volumes can also be attached and mapped after instance boot using the volume service, specifying block device mappings at launch time is especially useful when it is necessary to resize the root volume.

The code below demonstrates how to resize the root volume. For more information, refer to LaunchConfig.

lc = provider.compute.instances.create_launch_config()
lc.add_volume_device(source=img, size=11, is_root=True)
inst = provider.compute.instances.create(
    name='cloudbridge-bdm', image=img,  vm_type=vm_type,
    launch_config=lc, key_pair=kp, vm_firewalls=[fw],
    subnet=subnet, zone=zone)

where img is the Image object to use for the root volume.

After launch

After an instance has launched, you can access its properties:

# Wait until ready
inst.wait_till_ready()  # This is a blocking call
inst.state
# 'running'

Depending on the provider’s networking setup, it may be necessary to explicitly assign a floating IP address to your instance. This can be done as follows:

# Create a new floating IP address
fip = provider.networking.floating_ips.create()
# Assign the desired IP to the instance
inst.add_floating_ip(fip)
inst.refresh()
inst.public_ips
# [u'149.165.168.143']