1. OpenStack
Overview
Mirantis, Inc.

2. What is OpenStack?
"Open source software for building
private and public clouds"

3. OpenStack capabilities
● VMs on demand
○ provisioning
○ snapshotting
● Volumes
● Networks
● Multi-tenancy
○ quotas for different users
○ user can be associated with multiple tenants
● Object storage for VM images and arbitrary
files

4. OpenStack History
● July 2010 - Initial announcement
● October 2010 - Austin Release
● February 2011 - Bexar Release
● April 2011 - Cactus Release
● October 2011 - Diablo Release
● April 2012 - Essex Release
● October 2012 - Folsom Release
● April 2013 - Grizzly Release

5. OpenStack Projects
● Nova (Compute)
● Glance (Image Service)
● Swift (Object Store)
● Keystone (auth)
● Horizon (Dashboard)
● Quantum (Network) formerly nova-network
● Cinder (Block Storage) formerly nova-volume

6. OpenStack Projects: Relationship

7. OpenStack: Deployment Topology
control cluster
"one to one" relationship with
Horizon Keystone each deployment instance.
Quantum Glance
Cloud Ctrl.
Cinder
(nova)
compute cluster storage cluster
compute compute compute storage storage storage
node node node node node node
compute compute compute storage storage storage
node node node node node node

8. OpenStack Projects: Detailed View (Essex)
Horizon CLI
Keystone Glance
nova: Cloud Controller
nova-api endpoint glance-api
glance-registry
scheduler nova: Compute
nova-db
nova-network nova-compute Swift
que
nova-volume ue hypervisor proxy-server
object
Shared Storage store

9. Still part of nova
Horizon CLI
Keystone Glance
nova: Cloud Controller
nova-api endpoint glance-api
glance-registry
scheduler nova: Compute
nova-db
nova-network nova-compute Swift
que
nova-volume ue hypervisor proxy-server
object
Shared Storage store

10. UI: horizon or CLI Keystone
keystone
server
nova compute node
keystone
-db
controller nova: Hypervisor
queu nova-
Compute
nova-api e compute
Quantum
V
M quantum
scheduler server
nova-db Network
quantum
-db
Cinder block Glance quantum
storage plugin
endpoint queu
e node glance-api
scheduler storage glance-registry Swift
cinder-vol proxy-server
glance
db object
cinder-db store

11. OpenStack Projects: Communication Types
HTTP
AMQP
SQL
natv. API
iSCSI
UI: horizon or CLI Keystone
keystone
server
nova compute node keyston
e-db
nova: Hypervisor
controller queu nova-
e Compute
compute
nova-api Quantum
V
M quantum
scheduler server
nova-db Network
quantum-
db
Cinder block storage
Glance quantum
node plugin/agt
cinder-api queu
e glance-api
storage
scheduler glance-registry Swift
cinder-vol network node proxy-server
dhcp serv. glance
cinder- object
db
db router/gw store

12. Use Case: provisioning a VM

13. Initial State
Tenant is created, provisioning
quota is available, user has an
access to Horizon/CLI
UI: horizon or CLI Keystone
keystone
server
nova compute node keyston
e-db
nova: Hypervisor
controller queu nova-
e Compute
compute
nova-api Quantum
V
M quantum
scheduler server
nova-db
Network
quantum-
db
Cinder block storage
Glance quantum
node plugin/agt
cinder-api queu
e glance-api
storage
scheduler glance-registry Swift
cinder-vol network node proxy-server
dhcp serv. glance
cinder- object
db
db router/gw store

14. Step 1: Request VM Provisioning via UI/CLI
User specifies VM params: name, flavor,
keys, etc. and hits "Create" button
UI: horizon or CLI Keystone
keystone
server
nova compute node keyston
e-db
nova: Hypervisor
controller queu nova-
e Compute
compute
nova-api Quantum
V
M quantum
scheduler server
nova-db
Network
quantum-
db
Cinder block storage
Glance quantum
node plugin/agt
cinder-api queu
e glance-api
storage
scheduler glance-registry Swift
cinder-vol network node proxy-server
dhcp serv. glance
cinder- object
db
db router/gw store

15. Step 1: Request Provisioning via UI/CLI
● From UI
a. Login to Horizon
b. Specify params of VM in "Create VM" form
c. Hit "Create" button
● Under the hood
a. Form params are converted to POST data
b. "Create" request initiate HTTP POST request to back-
end
■ To Keystone if auth token is not cached
■ To nova-api if auth token hasn't expired yet

16. Horizon
"The OpenStack Dashboard (Horizon)
provides a baseline user interface for
managing OpenStack services."

17. Step 2: Validate Auth Data Horizon sends HTTP request to
Keystone. Auth info is specified
in HTTP headers.
UI: horizon or CLI Keystone
keystone
server
nova compute node keyston
e-db
nova: Hypervisor
controller queu nova-
e Compute
compute
nova-api Quantum
V
M quantum
scheduler server
nova-db
Network
quantum-
db
Cinder block storage
Glance quantum
node plugin/agt
cinder-api queu
e glance-api
storage
scheduler glance-registry Swift
cinder-vol network node proxy-server
dhcp serv. glance
cinder- object
db
db router/gw store

18. Keystone
"Keystone is an OpenStack project that
provides Identity, Token, Catalog and
Policy services for use specifically by
projects in the OpenStack family."

19. Keystone Architecture

20. Keystone: auth flow

21. Step 2: Validate Auth Data Keystone sends temporary
token back to Horizon via HTTP.
UI: horizon or CLI Keystone
keystone
server
nova compute node keyston
e-db
nova: Hypervisor
controller queu nova-
e Compute
compute
nova-api Quantum
V
M quantum
scheduler server
nova-db
Network
quantum-
db
Cinder block storage
Glance quantum
node plugin/agt
cinder-api queu
e glance-api
storage
scheduler glance-registry Swift
cinder-vol network node proxy-server
dhcp serv. glance
cinder- object
db
db router/gw store

22. Step 3: Send API request to nova-api
Horizon sends POST request to nova-
api (signed with given token).
UI: horizon or CLI Keystone
keystone
server
nova compute node keyston
e-db
nova: Hypervisor
controller queu nova-
e Compute
compute
nova-api Quantum
V
M quantum
scheduler server
nova-db Network
quantum-
db
Cinder block storage
Glance quantum
node plugin/agt
cinder-api queu
e glance-api
storage
scheduler glance-registry Swift
cinder-vol network node proxy-server
dhcp serv. glance
cinder- object
db
db router/gw store

23. Step 4: Validate API Token nova-api sends HTTP request to
validate API token to Keystone.
UI: horizon or CLI Keystone
keystone
server
nova compute node keyston
e-db
nova: Hypervisor
controller queu nova-
e Compute
compute
nova-api Quantum
V
M quantum
scheduler server
nova-db Network
quantum-
db
Cinder block storage
Glance quantum
node plugin/agt
cinder-api queu
e glance-api
storage
scheduler glance-registry Swift
cinder-vol network node proxy-server
dhcp serv. glance
cinder- object
db
db router/gw store

24. Step 4: Validate API Token Keystone validates API token
and sends HTTP response with
token acceptance/rejection info.
UI: horizon or CLI Keystone
keystone
server
nova compute node keyston
e-db
nova: Hypervisor
controller queu nova-
e Compute
compute
nova-api Quantum
V
M quantum
scheduler server
nova-db
Network
quantum-
db
Cinder block storage
Glance quantum
node plugin/agt
cinder-api queu
e glance-api
storage
scheduler glance-registry Swift
cinder-vol network node proxy-server
dhcp serv. glance
cinder- object
db
db router/gw store

25. Step 5: Process API request nova-api parses request and
validates it by fetching data from
nova-db. If the request is valid, it
saves initia db entry about VM
to the database.
UI: horizon or CLI Keystone
keystone
server
nova compute node keyston
e-db
nova: Hypervisor
controller queu nova-
e Compute
compute
nova-api Quantum
V
M quantum
scheduler server
nova-db Network
quantum-
db
Cinder block storage
Glance quantum
node plugin/agt
cinder-api queu
e glance-api
storage
scheduler glance-registry Swift
cinder-vol network node proxy-server
dhcp serv. glance
cinder- object
db
db router/gw store

26. nova-api
"nova-api is a RESTful API web service
which is used to interact with nova"

27. nova-api clients

28. nova database
"nova database stores current state of
all objects in compute cluster."

29. Step 6: Publish provisioning request to queue
nova-api makes rpc.call to scheduler.
It publishes a short message to
scheduler queue with VM info.
UI: horizon or CLI Keystone
keystone
server
nova compute node keyston
e-db
nova: Hypervisor
controller queu nova-
e Compute
compute
nova-api Quantum
V
M quantum
scheduler server
nova-db
Network
quantum-
db
Cinder block storage
Glance quantum
node plugin/agt
cinder-api queu
e glance-api
storage
scheduler glance-registry Swift
cinder-vol network node proxy-server
dhcp serv. glance
cinder- object
db
db router/gw store

30. Step 6: Pick up provisioning request
scheduler picks up the message
from MQ.
UI: horizon or CLI Keystone
keystone
server
nova compute node keyston
e-db
nova: Hypervisor
controller queu nova-
e Compute
compute
nova-api Quantum
V
M quantum
scheduler server
nova-db Network
quantum-
db
Cinder block storage
Glance quantum
node plugin/agt
cinder-api queu
e glance-api
storage
scheduler glance-registry Swift
cinder-vol network node proxy-server
dhcp serv. glance
cinder- db object
db router/gw store

31. Message queue
"Message queue is a unified way for
collaboration between nova
components."

32. Step 7: Schedule provisioning Scheduler fetches information
about the whole cluster from
database and based on this info
selects the most applicable
compute host.
UI: horizon or CLI Keystone
keystone
server
nova compute node keyston
e-db
nova: Hypervisor
controller queu nova-
e Compute
compute
nova-api Quantum
V
M quantum
scheduler server
nova-db Network
quantum-
db
Cinder block storage
Glance quantum
node plugin/agt
cinder-api queu
e glance-api
storage
scheduler glance-registry Swift
cinder-vol network node proxy-server
dhcp serv. glance
cinder- object
db
db router/gw store

33. nova-scheduler
"nova-scheduler is a daemon, which
determines, on which compute host
the request should run."

34. nova-scheduler: available schedulers
Scheduler Description
Chance Picks a host that is up at random
Simple Picks a host that is up and has the
fewest running instances
Filter Picks the best-suited host which
satisfies selected filter
Multi A scheduler that holds multiple sub-
schedulers

35. Step 8: Start VM provisioning on compute node
Scheduler publishes message to the
compute queue (based on host ID)
and triggers VM provisioning
UI: horizon or CLI Keystone
keystone
server
nova compute node keyston
e-db
nova: Hypervisor
controller queu nova-
e Compute
compute
nova-api Quantum
V
M quantum
scheduler server
nova-db Network
quantum-
db
Cinder block storage
Glance quantum
node plugin/agt
cinder-api queu
e glance-api
storage
scheduler glance-registry Swift
cinder-vol network node proxy-server
dhcp serv. glance
cinder- object
db
db router/gw store

36. Step 9: Start VM rendering via hypervisor
nova-compute fetches information
about VM from DB, creates a command
to hypervisor and delegates VM
rendering to hypervisor.
UI: horizon or CLI Keystone
keystone
server
nova compute node keyston
e-db
nova: Hypervisor
controller queu nova-
e Compute
compute
nova-api Quantum
V
M quantum
scheduler server
nova-db Network
quantum-
db
Cinder block storage
Glance quantum
node plugin/agt
cinder-api queu
e glance-api
storage
scheduler glance-registry Swift
cinder-vol network node proxy-server
dhcp serv. glance
cinder- object
db
db router/gw store

37. nova-compute
"nova-compute is a worker daemon,
which primarily creates and terminates
VMs via hypervisor API."

38. nova-compute drivers
nova-compute
XCP VMWare HyperV LPAR libvirt
VM VM VM VM
VM VM VM VM KVM Xen Qemu LXC
VM VM VM VM
VM VM VM VM

39. Step 10: Configure network nova-compute makes a call to
quantum-api to provision
network for the instance
UI: horizon or CLI Keystone
keystone
server
nova compute node keyston
e-db
nova: Hypervisor
controller queu nova-
e Compute
compute
nova-api Quantum
V
M quantum
scheduler server
nova-db
Network
quantum-
db
Cinder block storage
Glance quantum
node plugin/agt
cinder-api queu
e glance-api
storage
scheduler glance-registry Swift
cinder-vol network node
proxy-server
dhcp serv. glance
cinder- object
db
db router/gw store

40. Step 11: configure network
quantum configures IP,
gateway, L2 connectivity
UI: horizon or CLI Keystone
keystone
server
nova compute node keyston
e-db
nova: Hypervisor
controller queu nova-
e Compute
compute
nova-api Quantum
V
M quantum
scheduler server
nova-db Network
quantum-
db
Cinder block storage
Glance quantum
node plugin/agt
cinder-api queu
e glance-api
storage
scheduler glance-registry Swift
cinder-vol network node proxy-server
dhcp serv. glance
cinder- object
db
db router/gw store

41. Step 12: Request volume attachment
It is assumed a volume is already
created. Nova-compute contacts
cinder to get volume data.
UI: horizon or CLI Keystone
keystone
server
nova compute node keyston
e-db
nova: Hypervisor
controller queu nova-
e Compute
compute
nova-api Quantum
V
M quantum
scheduler server
nova-db Network
quantum-
db
Cinder block Glance quantum
queu plugin/agt
cinder-api storage glance-api
e node
scheduler storage glance-registry Swift
cinder-vol proxy-server
glance
cinder- object
db
db store

42. Step 12: Request volume attachment
Nova-compute sets up iSCSI initiator
& instructs the hypervisor to mount
iSCSI vol. as a new block device
UI: horizon or CLI Keystone
keystone
server
nova compute node keyston
e-db
nova: Hypervisor
controller queu nova-
e Compute
compute
nova-api Quantum
V
M quantum
scheduler server
nova-db Network
quantum-
db
Cinder block Glance quantum
queu plugin/agt
cinder-api storage glance-api
e node
scheduler storage glance-registry Swift
cinder-vol proxy-server
glance
cinder- object
db
db store

43. Step 12: Request volume attachment
iSCSI communication begins
UI: horizon or CLI Keystone
keystone
server
nova compute node keyston
e-db
nova: Hypervisor
controller queu nova-
e Compute
compute
nova-api Quantum
V
M quantum
scheduler server
nova-db
Network
quantum-
db
Cinder block storage
Glance quantum
node plugin/agt
cinder-api queu
e glance-api
storage
scheduler glance-registry Swift
cinder-vol network node proxy-server
dhcp serv. glance
cinder- object
db
db router/gw store

44. cinder
"block storage as-a-service"

45. cinder architecture

46. Step 13: Request VM Image from Glance
nova-compute requests VM
image from Glance via Image ID
UI: horizon or CLI Keystone
keystone
server
nova compute node keyston
e-db
nova: Hypervisor
controller queu nova-
e Compute
compute
nova-api Quantum
V
M quantum
scheduler server
nova-db Network
quantum-
db
Cinder block storage
Glance quantum
node plugin/agt
cinder-api queu
e glance-api
storage
scheduler glance-registry Swift
cinder-vol network node proxy-server
dhcp serv. glance
cinder- object
db
db router/gw store

47. Glance
"The Glance project provides services for
discovering, registering, and retrieving virtual
machine images."

48. Step 14: Get Image URI from Glance
If image with given image ID can
be found - return URI
UI: horizon or CLI Keystone
keystone
server
nova compute node keyston
e-db
nova: Hypervisor
controller queu nova-
e Compute
compute
nova-api Quantum
V
M quantum
scheduler server
nova-db Network
quantum-
db
Cinder block storage
Glance quantum
node plugin/agt
cinder-api queu
e glance-api
storage
scheduler glance-registry Swift
cinder-vol network node proxy-server
dhcp serv. glance
cinder- object
db
db router/gw store

49. Step 15: Download image from Swift
nova-compute downloads image using
URI, given by Glance, from Glance's back-
end. After downloading - it renders it.
UI: horizon or CLI Keystone
keystone
server
nova compute node keyston
e-db
nova: Hypervisor
controller queu nova-
e Compute
compute
nova-api Quantum
V
M quantum
scheduler server
nova-db Network
quantum-
db
Cinder block storage
Glance quantum
node plugin/agt
cinder-api queu
e glance-api
storage
scheduler glance-registry Swift
cinder-vol network node proxy-server
dhcp serv. glance
cinder- object
db
db router/gw store

50. Initial State
UI: horizon or CLI Keystone
keystone
server
nova compute node keyston
e-db
nova: Hypervisor
controller queu nova-
e Compute
compute
nova-api Quantum
V
M quantum
scheduler server
nova-db Network
quantum-
db
Cinder block storage
Glance quantum
node plugin/agt
cinder-api queu
e glance-api
storage
scheduler glance-registry Swift
cinder-vol network node proxy-server
dhcp serv. glance
cinder- object
db
db router/gw store

51. www.mirantis.com