Fog is a library for connecting to cloud computing services like OpenStack. It provides a common interface to services like compute, identity, volumes, images, storage and network. Fog follows a simple structure, making requests to cloud APIs and providing Ruby object models and collections. It includes mock and real connections. Fog has close integration with OpenStack, connecting to services like Nova, Keystone, Glance and Swift.

1. Introduction to Fog
and Openstack
Hunter Nield - 1/3/2013
Twitter: @hunternield

2. Fogとは
• 複数のクラウド・サービスを接続する共通インター
フェイス
• オープンソース Ruby ライブラリ (MIT License)
• OpenStack への接続が容易
• http://fog.io
• https://github.com/fog/fog

3. Fogの歴史
• 2010年 Wesley Beary (geemus on Github) に
より開始
• 初期バージョンは Amazon、Rackspace、
Slicehostのみ

4. Fog と OpenStack の歴史
• Diablo バージョンにて開発開始
• Morphlabs が Essex からサポートを始め、
Folsom、その後のバージョンと継続する予
定。

5. Basics
Fog provides high level interfaces to cloud services

6. Services
Fog Services map closely to the Openstack Services

7. Compute
Connects to the Openstack Nova API for managing
Instances (Servers), Security Groups, Floating IPs, etc
http://rubydoc.info/gems/fog/1.9.0/Fog/Compute/OpenStack

8. Identity
Connects to the Openstack Keystone API for managing Users, Tenants and Authentication
http://rubydoc.info/gems/fog/1.9.0/Fog/Identity/OpenStack

9. Volumes
Connects to the Openstack Nova/Cinder API for managing Block Storage
http://rubydoc.info/gems/fog/1.9.0/Fog/Volume/OpenStack

10. Images
Connects to the Openstack Glance API for managing VM Images and Snapshots
http://rubydoc.info/gems/fog/1.9.0/Fog/Images/OpenStack

11. Storage
Connects to the Openstack Swift API for managing Object Storage
http://rubydoc.info/gems/fog/1.9.0/Fog/Storage/OpenStack

12. Network
Connects to the Openstack Quantum API for managing Networks
http://rubydoc.info/gems/fog/1.9.0/Fog/Network/OpenStack

13. Internals
Fog follows a simple structure to handle the
management of cloud services

14. Requests
Query the cloud service APIs

15. Mock
• Test data to return example API responses
• Requires no network connection

16. Mock (Example)
class Mock
def list_flavors
response = Excon::Response.new
response.status = 200
response.body = {
'flavors' => [
{ 'name' => '256 server', 'id' => '1', 'links' => ['https://itdoesntmatterwhatshere.heh'] },
{ 'name' => '512 server', 'id' => '2', 'links' => ['https://itdoesntmatterwhatshere.heh'] },
{ 'name' => '1GB server', 'id' => '3', 'links' => ['https://itdoesntmatterwhatshere.heh'] },
{ 'name' => '2GB server', 'id' => '4', 'links' => ['https://itdoesntmatterwhatshere.heh'] },
{ 'name' => '4GB server', 'id' => '5', 'links' => ['https://itdoesntmatterwhatshere.heh'] },
{ 'name' => '8GB server', 'id' => '6', 'links' => ['https://itdoesntmatterwhatshere.heh'] },
{ 'name' => '15.5GB server', 'id' => '7', 'links' => ['https://
itdoesntmatterwhatshere.heh'] }
]
}
response
end
end

17. Real
• Returns actual data from the API

18. Real (Example)
class Real
def list_flavors
request(
:expects => [200, 203],
:method => 'GET',
:path => 'flavors.json'
)
end
end

19. Models
• Ruby Object representation of a Cloud
Service Entity (Instance, Image, etc)
• Uses one or many ‘Request’ methods to
retrieve data about an Entity
• Includes convenience methods for easy
access

20. Models (Example)
class Server < Fog::Compute::Server
identity :id
attribute :instance_name, :aliases => 'OS-EXT-SRV-ATTR:instance_name'
attribute :addresses
attribute :flavor
attribute :host_id, :aliases => 'hostId'
attribute :image
attribute :metadata
attribute :links
attribute :name
attribute :progress
attribute :accessIPv4
attribute :accessIPv6
attribute :state, :aliases => 'status'
attribute :created, :type => :time
attribute :updated, :type => :time
def ready?
self.state == 'ACTIVE'
end
def reboot(type = 'SOFT')
requires :id
service.reboot_server(id, type)
true
end
end

21. Collections
• Ruby Object representation of many groups of
Cloud Service Entities (Instances, Images,
etc)
• Handles querying and iteration of multiple
models of a single type

22. Collections (Example)
class Servers < Fog::Collection
model Fog::Compute::OpenStack::Server
def all(filters = filters)
self.filters = filters
data = service.list_servers_detail(filters).body['servers']
load(data)
end
def get(server_id)
if server = service.get_server_details(server_id).body['server']
new(server)
end
rescue Fog::Compute::OpenStack::NotFound
nil
end
end

23. Collection Servers
Models Server Server Server Server

24. Other methods
Specifically for Openstack

25. • service.unscoped_token
• The reusable token which can be used to retrieve scoped tokens “auth_token” on each
tenant.
• service.auth_token
• The current authentication token sent to OpenStack on each request as a header (“X-
Auth-Token”).
• service.current_user
• The Hash representation of the JSON returned information about the current user
returned by OpenStack upon authentication.
• service.current_tenant
• The Hash representation of the JSON returned information about the current tenant
returned by OpenStack upon authentication.
• service.credentials
• A convenience method to extract needed credentials to easily instantiate a new usable
service object. The new service object uses the “auth_token” returned by the
OpenStack API and not the provided username and password originally used for
authentication.

26. Example

27. Requirements
• Ruby (1.8.7, 1.9.2 or 1.9.3)
• Fog (Installed via: gem install fog)

28. Connection
# Connect to Openstack Nova
>> compute = Fog::Compute.new({:provider => 'openstack', :openstack_tenant => 'demo', :openstack_api_key =>
'yourpassword', :openstack_username => 'admin', :openstack_auth_url => 'http://localhost:35357/v2.0/tokens'})
#<Fog::Compute::OpenStack::Real:25457260 @openstack_region=nil @openstack_auth_token=nil
@openstack_username="admin" @openstack_service_type=["nova", "compute"]
@auth_token_expiration="2013-02-21T10:30:10Z" ... snip ... @tenant_id="ee1b6e1715644f2ca020c4190769d496"
@openstack_identity_public_endpoint="http://localhost:5000/v2.0" @openstack_management_url="http://localhost:
8774/v2/ee1b6e1715644f2ca020c4190769d496" @port=8774 @scheme="http" @openstack_service_name=nil>
# Query the user
>> compute.current_user
{"username"=>"admin", "roles_links"=>[], "id"=>"5b772e8e179249aeb7152742a4b4f6e9", "roles"=>[{"name"=>"admin"},
{"name"=>"project_manager"}, {"name"=>"Member"}], "name"=>"admin"}
# Get information about the tenant
>> compute.current_tenant
{"enabled"=>true, "description"=>"Demo Account", "name"=>"demo", "id"=>"ee1b6e1715644f2ca020c4190769d496"}
# Check the current state of the running instances
>> compute.list_servers
#<Excon::Response:0x000000030b1a28 @headers={"X-Compute-Request-Id"=>"req-eb228f6f-bec7-4fe3-8d41-69ad69dbee43",
"Content-Type"=>"application/json", "Content-Length"=>"15", "Date"=>"Wed, 20 Feb 2013 10:30:13 GMT"},
@status=200, @remote_ip="127.0.0.1", @body={"servers"=>[]}>

29. Servers
# Get a flavor (VM Size) to use for starting a instance
>> flavor = compute.list_flavors.body['flavors'].first
{"id"=>"2", "links"=>[{"href"=>"http://localhost:8774/v2/ee1b6e1715644f2ca020c4190769d496/flavors/2", "rel"=>"self"},
{"href"=>"http://localhost:8774/ee1b6e1715644f2ca020c4190769d496/flavors/2", "rel"=>"bookmark"}], "name"=>"m1.small"}
# Get an image to use for starting a instance
>> image = compute.list_images.body['images'].first
{"id"=>"10a11aa4-3d9c-49e5-988c-3fde3cf37842", "links"=>[{"href"=>"http://localhost:8774/v2/
ee1b6e1715644f2ca020c4190769d496/images/10a11aa4-3d9c-49e5-988c-3fde3cf37842", "rel"=>"self"}, {"href"=>"http://
localhost:8774/ee1b6e1715644f2ca020c4190769d496/images/10a11aa4-3d9c-49e5-988c-3fde3cf37842", "rel"=>"bookmark"},
{"href"=>"http://10.50.2.1:9292/ee1b6e1715644f2ca020c4190769d496/images/10a11aa4-3d9c-49e5-988c-3fde3cf37842",
"type"=>"application/vnd.openstack.image", "rel"=>"alternate"}], "name"=>"'64Bit_Ubuntu_12.04'"}
# Boot a new server
>> compute.create_server('MyFirstServer', image['id'], flavor['id'])
#<Excon::Response:0x000000031d3af0 @headers={"X-Compute-Request-Id"=>"req-a0379de9-a129-496b-b627-11853e0eefca",
"Location"=>"http://localhost:8774/v2/ee1b6e1715644f2ca020c4190769d496/servers/1334c522-ab51-403f-b694-0efd92ef0b10",
"Content-Type"=>"application/json", "Content-Length"=>"462", "Date"=>"Wed, 20 Feb 2013 10:36:37 GMT"}, @status=202,
@remote_ip="127.0.0.1", @body={"server"=>{"security_groups"=>[{"name"=>"default"}], "OS-DCF:diskConfig"=>"MANUAL",
"id"=>"1334c522-ab51-403f-b694-0efd92ef0b10", "links"=>[{"href"=>"http://localhost:8774/v2/
ee1b6e1715644f2ca020c4190769d496/servers/1334c522-ab51-403f-b694-0efd92ef0b10", "rel"=>"self"}, {"href"=>"http://
localhost:8774/ee1b6e1715644f2ca020c4190769d496/servers/1334c522-ab51-403f-b694-0efd92ef0b10", "rel"=>"bookmark"}],
"adminPass"=>"maUXeZE76o64"}}>
# Check the current state of running instances
>> servers = compute.list_servers.body['servers']
#<Excon::Response:0x000000031e16c8 @headers={"X-Compute-Request-Id"=>"req-cae13781-1377-4fc5-a8d2-77394468344d",
"Content-Type"=>"application/json", "Content-Length"=>"388", "Date"=>"Wed, 20 Feb 2013 10:37:01 GMT"}, @status=200,
@remote_ip="127.0.0.1", @body={"servers"=>[{"id"=>"1334c522-ab51-403f-b694-0efd92ef0b10", "links"=>[{"href"=>"http://
localhost:8774/v2/ee1b6e1715644f2ca020c4190769d496/servers/1334c522-ab51-403f-b694-0efd92ef0b10", "rel"=>"self"},
{"href"=>"http://localhost:8774/ee1b6e1715644f2ca020c4190769d496/servers/1334c522-ab51-403f-b694-0efd92ef0b10",
"rel"=>"bookmark"}], "name"=>"MyFirstServer"}]}>

30. Model Queries
# Example of a Collection query for the same data
>> compute.servers
<Fog::Compute::OpenStack::Servers
filters={}
[
<Fog::Compute::OpenStack::Server
id="1334c522-ab51-403f-b694-0efd92ef0b10",
instance_name=nil,
addresses={"novanetwork"=>[{"version"=>4, "addr"=>"10.2.0.6"}]},
flavor={"id"=>"2", "links"=>[{"href"=>"http://localhost:8774/ee1b6e1715644f2ca020c4190769d496/flavors/2", "rel"=>"bookmark"}]},
host_id="c1e95b9f69157e41baebad3092bd069baaf840215ecbee7edddd9bb2",
image={"id"=>"10a11aa4-3d9c-49e5-988c-3fde3cf37842", "links"=>[{"href"=>"http://localhost:8774/../images/...",
"rel"=>"bookmark"}]},
metadata= <Fog::Compute::OpenStack::Metadata
[]
>,
links=[{"href"=>"http://localhost:8774/v2/.../servers/...", "rel"=>"self"}, {"href"=>"http://localhost:8774/.../servers/...",
"rel"=>"bookmark"}],
name="MyFirstServer",
personality=nil,
progress=0,
accessIPv4="",
accessIPv6="",
availability_zone=nil,
user_data_encoded=nil,
state="ACTIVE",
created=2013-02-20 10:36:37 UTC,
updated=2013-02-20 10:37:24 UTC,
tenant_id="ee1b6e1715644f2ca020c4190769d496",
user_id="5b772e8e179249aeb7152742a4b4f6e9",
key_name=nil,
fault=nil,
os_dcf_disk_config="MANUAL",
os_ext_srv_attr_host="cn26.la-1-2.morphlabs.net",
os_ext_srv_attr_hypervisor_hostname="cn26.la-1-2.morphlabs.net",
os_ext_srv_attr_instance_name="instance-00000038",
os_ext_sts_power_state=1,
os_ext_sts_task_state=nil,
os_ext_sts_vm_state="active"
>
]
>

31. Volumes
# Create a 1GB persistent volume
>> compute.create_volume("MyFirstVolume", "Test Volume", 1000)
# <Excon::Response:0x00000003257940 @headers={"X-Compute-Request-Id"=>"req-e98c1f91-d2b9-49cc-bf14-353fd8fa46be",
"Location"=>"http://localhost:8774/v2/ee1b6e1715644f2ca020c4190769d496/os-volumes?
ignore_awful_caching1361357305/664000aa-e275-4e86-a477-7be86927979b", "Content-Type"=>"application/json", "Content-
Length"=>"311", "Date"=>"Wed, 20 Feb 2013 10:48:27 GMT"}, @status=200, @remote_ip="127.0.0.1",
@body={"volume"=>{"status"=>"creating", "displayDescription"=>"Test Volume", "availabilityZone"=>"nova",
"displayName"=>"MyFirstVolume", "attachments"=>[{}], "volumeType"=>nil, "snapshotId"=>nil, "metadata"=>{},
"id"=>"664000aa-e275-4e86-a477-7be86927979b", "createdAt"=>"2013-02-20T10:48:26.709904", "size"=>1000}}>
# Query information about the current volumes for this tenant
>> compute.list_volumes.body['volumes'].first
{"status"=>"available", "displayDescription"=>"Test Volume", "availabilityZone"=>"nova",
"displayName"=>"MyFirstVolume", "attachments"=>[{}], "volumeType"=>nil, "snapshotId"=>nil, "metadata"=>{},
"id"=>"664000aa-e275-4e86-a477-7be86927979b", "createdAt"=>"2013-02-20T10:48:26.000000", "size"=>1000}
# Attach the Volume to the running server
>> compute.attach_volume(compute.list_volumes.body['volumes'].first['id'], compute.servers.first.id, "vdc")
#<Excon::Response:0x000000032b0680 @headers={"X-Compute-Request-Id"=>"req-b6a2bad1-b69d-4abc-a3e6-88d1fc044827",
"Content-Type"=>"application/json", "Content-Length"=>"194", "Date"=>"Wed, 20 Feb 2013 10:54:12 GMT"}, @status=200,
@remote_ip="127.0.0.1", @body={"volumeAttachment"=>{"device"=>"/dev/vdc", "serverId"=>"1334c522-ab51-403f-
b694-0efd92ef0b10", "id"=>"664000aa-e275-4e86-a477-7be86927979b", "volumeId"=>"664000aa-e275-4e86-a477-7be86927979b"}}>
# Check volumes by querying the Volumes collection
>> compute.volumes.first
<Fog::Compute::OpenStack::Volume
id="664000aa-e275-4e86-a477-7be86927979b",
name="MyFirstVolume",
description="Test Volume",
status="in-use",
size=1000,
type=nil,
snapshot_id=nil,
availability_zone="nova",
created_at="2013-02-20T10:48:26.000000",
attachments=[{"device"=>"/dev/vdc", "serverId"=>"1334c522-ab51-403f-b694-0efd92ef0b10", "id"=>"664000aa-e275-4e86-
a477-7be86927979b", "volumeId"=>"664000aa-e275-4e86-a477-7be86927979b"}]
>

32. Cleanup
# Remove the Volume from the instance
>> compute.detach_volume(compute.servers.first.id, compute.list_volumes.body['volumes'].first['id'])
#<Excon::Response:0x0000000338e278 @headers={"Content-Type"=>"text/html; charset=UTF-8", "Content-Length"=>"0",
"Date"=>"Wed, 20 Feb 2013 10:58:10 GMT"}, @status=202, @remote_ip="127.0.0.1", @body="">
# Delete the Volume from the system
>> compute.delete_volume(compute.list_volumes.body['volumes'].first['id'])
#<Excon::Response:0x0000000339f6b8 @headers={"Content-Type"=>"text/html; charset=UTF-8", "Content-Length"=>"0",
"Date"=>"Wed, 20 Feb 2013 10:59:22 GMT"}, @status=202, @remote_ip="127.0.0.1", @body="">
# Check volumes again
>> compute.list_volumes.body['volumes']
# []
# Cleanup the system by deleting the instance
compute.delete_server(servers.first['id'])
#<Excon::Response:0x000000033b9dd8 @headers={"Content-Length"=>"0", "X-Compute-Request-Id"=>"req-
ef6c799f-7832-4edf-9929-387d5957320a", "Content-Type"=>"application/json", "Date"=>"Wed, 20 Feb 2013 11:00:17
GMT"}, @status=204, @remote_ip="127.0.0.1", @body="">

33. Thank you!