The Evolution of Glance API: On the Way From v1 to v3

THE EVOLUTION OF
GLANCE API
On the Way from v1 to v3

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•  @br14nr
•  Freenode: rosmaita
•  OpenStack ATC since Folsom
•  Driver for Glance and Searchlight
ABOUT ME
Brian Rosmaita
Senior Software Developer, Rackspace

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GLANCE AT RACKSPACE
(Official Glance Logo)

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OUTLINE
•  When Nikhil asked me to fill in for him, I took the title too literally
•  The Images v1 API
– Not an exhaustive look, just some highlights
– Including interesting observations
•  The Images v2 API
– Also including interesting observations, and also not exhaustive
•  The Future
– Just a little foreshadowing for Alex’s presentation

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IN THE BEGINNING …
There was Nova …
… well, Nova and Swift

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THE EVOLUTION OF OPENSTACK
•  Stuart McLaren created a really nice diagram of the evolution of OpenStack
projects for a talk at the Liberty design summit in Vancouver, and he kindly agreed
to let me use it today
•  Powerpoint, however, is unkindly displaying the PDF he gave me as a solid black
box, so I will bail out to Acrobat here to show you the diagram

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AUSTIN RELEASE
•  October 21, 2010
•  Release of
– OpenStack Object Store
– OpenStack Compute
– OpenStack Clients

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C o r y W r i g h t a n d R i c k H a r r i s h a d
o r i g i n a l l y c r e a t e d a s e t o f e n d p o i n t s
c a l l e d T e l l e r a n d P a r a l l a x t h a t
e v e n t u a l l y b e c a m e t h e G l a n c e r e g i s t r y
a n d i m a g e s t r e a m i n g s e r v i c e s … T h e y
w e r e m o d e l e d a f t e r s i m i l a r i m a g e
s e r v i c e s i n s i d e t h e S l i c e h o s t
i n f r a s t r u c t u r e , i f I r e m e m b e r c o r r e c t l y .
Jay Pipes

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AUSTIN RELEASE
•  Partial implementation of an image registration and caching proxy named Glance
•  Not enabled by default
•  Only used by Nova with the OpenStack API
– When Nova uses the EC2 API, the existing S3-like objectstore is used for VM image
storage
•  Known issues
– Images without ramdisks are not supported at this time
– OpenStack Object Store does not support objects larger than 5 GB

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I s t a r t e d w o r k i n g w i t h C o r y a n d R i c k
o n w h a t w o u l d b e c o m e G l a n c e ( f r o m
t h e T e l l e r a n d P a r a l l a x c o d e ) i n t h e
A u s t i n t i m e f r a m e . F o r t h e l i f e o f m e ,
I c a n ’ t r e m e m b e r i f w e h a d a n y t h i n g
c a l l e d a P T L b a c k t h e n , o r e v e n w h e n
I b e c a m e G l a n c e ’ s P T L , o r e v e n
w h y ! : ) I t h i n k I j u s t k i n d o f f e l l i n t o
t h e s p o t o f P T L f o r G l a n c e a r o u n d t h e
A u s t i n r e l e a s e .
Jay Pipes

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BEXAR RELEASE
Features
•  Glance APIs (for registry and delivery) were unified, and a specific client class
created
– Images API version 1.0
•  Support for uploading disk images directly through the glance REST-ful API
•  Documentation for Glance is now available
•  The dependency on Twisted was removed. Glance now uses only Eventlet for its
server-side internals

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BEXAR RELEASE
Known issues
•  The S3 and Swift backends do not currently support the POST /images/ API
command in the Glance API
– These backends only currently support fetching disk images via GET calls.
•  Support for storing disk images in S3 and Swift directly through the Glance API is
planned for the Cactus release

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CACTUS RELEASE
Features
•  Images API continues at version 1.0
•  Introduction of the “glance” CLI tool
•  Introduction of disk_format and container_format metadata
•  Checksum verification for uploaded images
•  “Lots of other changes should go unnoticed”
– like: support for database schema migration, non-static versioning or standard use of
paste.deploy, ConfigParser and optparse

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DIABLO RELEASE
API Enhancements
•  Versioning in the API
– Needed because Images API version 1.1 is released!
– 1.1 becomes CURRENT, 1.0 becomes SUPPORTED
•  Custom ordering of results
•  Results filtering
•  Results limiting and pagination
•  New ISO disk format

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DIABLO RELEASE
Usability and performance improvements
•  Local filesystem LRU cache
•  Delayed deletion of images
•  Integration with Keystone authentication
•  Sharing images between tenants
•  Event notifications
•  Internationalization of error and output messages

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ESSEX RELEASE
Stabilization and Usability
•  Images API v 1.1 is CURRENT, 1.0 is SUPPORTED (unchanged from Diablo)
•  Contributors fixed 185 bugs and implemented 11 blueprints
– Role-based access control
– Introduction of the ‘protected’ image property
– Configurable number of Glance API processes
– Copy image data from external locations
– Image upload progress bar in the Glance CLI

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FOLSOM RELEASE
Features
•  Images API version 2.0 is introduced
– 2.0 and 1.1 are CURRENT
– 1.0 is SUPPORTED
•  The python-glanceclient is introduced
•  Client SSL certificate validation on glance-api
•  Tenant-specific storage in Swift
•  Image replication using glance-replicator

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WHY VERSION 2?
•  Version 1 of the Images API was not designed for human consumption
– GET v1/images/UUID returns image data in payload, image properties in headers
• Number of of allowed headers can be configured at multiple places in the request chain before
Glance ever sees them
• Various components in the request chain think nothing of monkeying with headers
• GET v2/{tenant_id}/servers/UUID returns a representation of an instance, not the instance itself
–  On analogy, GET v1/images/UUID should return a representation of the image
– Architectural considerations: v1 designed to use the Glance Registry (extra layer
between the Images API and the DB API)

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WHY VERSION 2?
•  Version 2 is will include features suitable for making the Images API “public”
– Anti-spam image sharing
– Property protections
– Image “import” vs. image “upload”
•  Architectural considerations
– Domain model
– Glance registry becomes optional

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GRIZZLY RELEASE
Features
– 2.1, 1.1 are CURRENT
– 2.0, 1.0 are SUPPORTED
•  API v2 Image Sharing
•  JSON PATCH draft 10 support
•  glance-control status: programmatically expose the status of the glance services
•  glance-manage downgrade: explicitly migrates a database down to the requested
version

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HAVANA RELEASE
Features
– 2.2, 1.1 are CURRENT
– 2.1, 2.0, 1.0 are SUPPORTED
•  Multiple image locations
•  Property protections
•  Registry API
•  Policies on image membership
•  Backend storage support: Sheepdog, Cinder, GridFS

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ICEHOUSE RELEASE
Features
•  Images API versions: no changes
•  Add VMware Datastore as Storage Backend
•  Adding image location selection strategy
•  A new field ‘virtual_size’ is added for image
•  API message localization
•  The calculation of storage quotas has been improved
•  0-based indices for location entries (per JSON-pointer RFC6901)

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JUNO RELEASE
Features
•  Images API versions: no changes
•  Asynchronous Processing
– v2/tasks endpoint introduced
•  Pull of glance.store into its own library
•  Metadata Definitions Catalog
– v2/metadefs endpoint introduced
•  Restricted policy for downloading images

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JUNO RELEASE
Mission statement change
•  “original” mission statement
– Merged June 11, 2014
– https://review.openstack.org/#/c/98001/
•  To provide services to store, browse, share, distribute and manage bootable disk
images

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JUNO RELEASE
Mission statement change
•  Merged July 10, 2014
– https://review.openstack.org/#/c/98002/
•  To provide a service where users can upload and discover data assets that are
meant to be used with other services, like images for Nova and templates for
Heat.

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KILO RELEASE
Features
•  Enhanced Image import process
– Basic support for Image conversion, Image Introspection
•  Reload configuration files on SIGHUP signal
•  Metadefs:
– Tag support, Support for multivalue operators, Software Metadata Definitions
•  Allow None values to be returned from the API
•  Digest algorithm is now configurable

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KILO RELEASE
API changes
•  Image “deactivation” (2 new API calls)
•  Images API versions
– 2.3 introduced as CURRENT
– 1.1 becomes SUPPORTED
– 1.0, 2.0, 2.1, 2.2 continue as SUPPORTED
•  Catalog Index Service experimental API

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KILO RELEASE
API changes
•  Downgrading v1 to SUPPORTED is a step toward the deprecation and ultimate
elimination of the v1 API

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LIBERTY RELEASE
Features
•  Added support for uploading signed images
•  Scrubbing of images in parallel is now possible
•  The health of a Glance node can be monitored using the healthcheck middleware
•  python-glanceclient now defaults to using Images API v2
•  Catalog Index Service becomes the “Searchlight” project

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T h e c u r r e n t G l a n c e ( v 1 a n d v 2 )
a r c h i t e c t u r e t r i e s t o h a n d l e t h r e e
d o m a i n s n a m e l y m e t a d a t a r e g i s t r y ,
i m a g e f o r m a t , a n d i n t e r f a c e t o s t o r e
i m a g e d a t a - b l o b s . I t b e c o m e s
i n e f f e c t i v e a t h a n d l i n g e a c h o f t h e m
a t l a r g e s c a l e m a i n l y a s t h e
s e p a r a t i o n o f c o n c e r n i s w e a k .
Nikhil Komawar

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I f i n d a n i n d e x i n g m e c h a n i s m b e t t e r
a t h a n d l i n g l a r g e s c a l e i m a g e &
r e l a t e d m e t a d a t a l i k e t h e p r o p e r t i e s ,
t a g s , a n d m e m b e r s i n f o ; a d e d i c a t e d
t r a n s f e r l o g i c t o b e t t e r h a n d l e l a r g e
s c a l e d a t a b l o b m o v e m e n t ; a n d s o m e
a s y n c h r o n o u s w a y t o c l e a n l y h a n d l e
t h e i m a g e i n t e r - o p e r a b l e f o r m a t t i n g .
Nikhil Komawar

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I n K i l o a n d L i b e r t y , I h a v e a t t e m p t e d
t o p r o v i d e a p l a t f o r m t o d e v e l o p e r s ,
o p e r a t o r s a n d p r o d u c t m a n a g e r s a l i k e
t o b r i n g G l a n c e t o a s t a t e t h a t w o u l d
h a n d l e e a c h o f t h e s e d o m a i n s i n a
b e t t e r m a n n e r .
Nikhil Komawar

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LIBERTY RELEASE
API changes
•  The Artifacts API is available for use
•  Artifacts API is exposed as v3 on the Glance endpoint
– 3.0 is EXPERIMENTAL
– 2.3 is CURRENT
– 2.2, 2.1, 2.0, 1.1, 1.0 are SUPPORTED

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WHY VERSION 3?
•  Generalization of Glance from cataloging and delivery of VM images to cataloging
and delivery of “digital artifacts”
•  Some of the shortcomings of Glance Images are addressed by artifacts
– Images are unversioned, artifacts are versioned
– Images are independent, artifacts can have dependency relations
– Images have a single payload
•  An artifact cataloging and delivery project would duplicate a lot of Glance
functionality

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WHAT ABOUT MITAKA?
•  That’s what we’re here in Tokyo to decide!
– Check your conference schedule for the Glance design sessions, pretty much running all
day tomorrow
•  Post summit:
– You can see what’s been approved for development at specs.openstack.org
– For items still under discussion, go to review.openstack.org
• Search for status:open project:openstack/glance-specs
– There will be a “priorities” document among the specs shortly after the summit
• https://review.openstack.org/#/c/230392

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THANKS TO THOSE WHO HELPED MAKE THIS TALK NECESSARY
JAY
PIPES
Bexar, Cactus,
Diablo, Essex
BRIAN
WALDON
Folsom, Grizzly
MARK
WASHENBERGER
Havana, Icehouse,
Juno
NIKHIL
KOMAWAR
Kilo, Liberty
FLAVIO
PERCOCO
Mitaka

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H i n d s i g h t i s , o f c o u r s e , 2 0 / 2 0 . I f I
h a d i t a l l t o d o o v e r a g a i n , I p r o b a b l y
w o u l d p u s h f o r n o t h a v i n g a n A P I /
i m a g e s t r e a m i n g e n d p o i n t a t a l l i n
G l a n c e , a n d j u s t h a v e G l a n c e b e a
g e n e r a l p u r p o s e m e t a d a t a r e g i s t r y .
Jay Pipes

O N E FA N AT I C A L P L AC E | S A N A N TO N I O , T X 7 8 21 8
U S S A L E S : 1 - 8 0 0 - 9 61 - 2 8 8 8 | U S S U P P O R T: 1 - 8 0 0 - 9 61 - 4 4 5 4 | W W W. R AC K S PAC E . C O M
© RACKSPACE LTD. | RACKSPACE® AND FANATICAL SUPPORT® ARE SERVICE MARKS OF RACKSPACE US, INC. REGISTERED IN THE UNITED STATES AND OTHER COUNTRIES. | WWW.RACKSPACE.COM
Thank you

DON’T GO ANYWHERE!
And now … ALEX TIVELKOV to speak about the v3 API

The Evolution of Glance API: On the Way From v1 to v3

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