The Open Cloud Computing Interface is a specification from Open Grid Forum which aims at interoperability between cloud computing providers. Based on a formal meta-model, it can be easily extended to address every kind of service oriented application.

1. Open Cloud Computing
Interface
Jean Parpaillon
Inria Research Engineer
OGF-44, EGI Spring Conference, May 2015, Lisbon

2. 21 May 2015 OGF-44 / EGI Spring Conference
REST API : a user point of view

3. 21 May 2015 OGF-44 / EGI Spring Conference
REST API : a user point of view
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Data format
– JSON format
– XML format
– Scalar data types (string, integer, float, etc)
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Data access protocol
– Filtering
– Sorting
– Pagination
– Authnz (tokens, etc), return codes, etc.
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Finally...
– Application level : data types (structures, relations, etc)

4. 21 May 2015 OGF-44 / EGI Spring Conference
REST API : a user point of view
●
Data format
– JSON format
– XML format
– Scalar data types (string, integer, float, etc)
●
Data access protocol
– Filtering
– Sorting
– Pagination
– Authnz (tokens, etc), return codes, etc.
●
Finally...
– Application level : data types (structures, relations, etc)
Schemas ?
One to rule them all ?
A single meta-model ?

5. Let's speak about a standard ?

6. 21 May 2015 OGF-44 / EGI Spring Conference
Let's speak about a standard for REST
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A standard
– Is not a catalog of schemas
– Is not a constraint for developers
– Must be implemented (implementable)
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A good standard
– Should allow to concentrate on the design, not the
implementation details
– Allow to build an ecosystem
– Allow to accelerate the development, not the contrary

7. 21 May 2015 OGF-44 / EGI Spring Conference
The Open Cloud Computing Interface
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OCCI is typed
– A ressource is an instance of a kind
– A kind is a named list of typed attributes and actions
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e.g. : compute : # cores (integer), RAM (float), etc
– Attribute : name, type, default value, mutability, etc.
– Action : an invocable operation on a ressource
– Kinds are inheritable

8. 21 May 2015 OGF-44 / EGI Spring Conference
The Open Cloud Computing Interface
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OCCI is extensible
– Resource can be associated with mixins
– Mixin: a named set of additional attributes and actions
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e.g. : IPNetworkInterface adds IP, netmask, etc to a
network interface
– User Mixin : aka « tags »
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e.g. : http://example.com/occi/mixins#my_project1

9. 21 May 2015 OGF-44 / EGI Spring Conference
The Open Cloud Computing Interface
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OCCI is relational
– Links are ressources with additional attributes
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occi.core.source : resource URI
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occi.core.target : URI
– A bounded collection is a list of ressources of the same
kind/mixin :
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e.g. : GET /collections/compute/
– An unbounded collection is a list of ressources with same prefix :
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e.g. : GET /myresources/

10. 21 May 2015 OGF-44 / EGI Spring Conference
The Open Cloud Computing Interface
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OCCI is self-described
– GET /-/ (capabilities)
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List of supported kinds
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List of supported mixins
– Capabilities returns collection's URL
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http://schemas.ogf.org/occi/infrastructure#compute
→ /collections/compute/

11. 21 May 2015 OGF-44 / EGI Spring Conference
The Open Cloud Computing Interface
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OCCI is meta-model based
– Model consistency checking
– Automatic model implementation
– Rendering independant
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text/plain, application/json, …
– Transport independant
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HTTP, ...

12. 21 May 2015 OGF-44 / EGI Spring Conference
OCCI Ecosystem
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Framework
– rOCCI (ruby)
– occi4java (not maintained)
– erocci (erlang/OTP)
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Specific implementations
– CompatibleOne
– PyOCNI
– OpenStack, OpenNebula, etc
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Limits
– Models are
language/extensions/lib dependant
– See
http://occi-wg/community/implemen
tations/
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Tools
– DoYouSpeakOcci : tests
– Monitoring (Intel)

13. 21 May 2015 OGF-44 / EGI Spring Conference
OCCI Infrastructure (model)

14. 21 May 2015 OGF-44 / EGI Spring Conference
Infrastructure OCCI Model Instance
occi.storage.size = 100 000
storage1 : Storage
occi.compute.architecture = 'x64'
occi.compute.cores = 4
occi.compute.hostname = 'vm1'
occi.compute.memory = 4
vm1: Compute
occi.compute.architecture = 'x64'
occi.compute.cores = 2
occi.compute.hostname = 'vm2'
occi.compute.memory = 16
vm2: Compute
occi.network.vlan = 12
occi.network.label = 'private'
occi.network.address = '10.1.0.0/16'
occi.network.gateway = '10.1.255.254'
network1 : Network
IPNetworking
mixin
occi.storagelink.deviceid = 'nfs :...'
occi.storagelink.mountpoint = '/mnt/scratch'
StorageLink
occi.storagelink.deviceid = 'nfs :...'
occi.storagelink.mountpoint = '/mnt/scratch'
StorageLink
occi.networkinterface.mac = 'aa:bb:cc:dd:ee:11'
occi.networkinterface.address = '10.1.0.100/16'
occi.networkinterface.gateway = '10.1.255.254'
occi.networkinterface.allocation = 'static'
NetworkInterface
occi.networkinterface.mac = 'aa:bb:cc:dd:ee:11'
occi.networkinterface.address = '10.1.0.100/16'
occi.networkinterface.gateway = '10.1.255.254'
occi.networkinterface.allocation = 'static'
NetworkInterface
IPNetworkInterface IPNetworkInterface
mixin mixin

15. 21 May 2015 OGF-44 / EGI Spring Conference
Questions / Feedback
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Occi-wg@ogf.org