Federated Cloud Technology

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Overview For users For resource providers Infrastructure status Site-specific configuration Architecture

Architecture Technology Roadmap FedCloud Task Force


EGI Federated Cloud provides the services and technologies to create federation of clouds (community, private or public clouds) that operate according to the preferences, choices and constraints set by its members and users. The EGI Cloud Federations are modeled around the concept of an abstract Cloud Management stack subsystem that is integrated with components of the EGI Core Infrastructure and that provides a set of agreed uniform interfaces within the community it provides services to. This page documents the technical solutions provided by EGI to create such federations. The Architecture page gives an overview of the federation model.

Single Sign-On for users

SSO Ensures that users of the federation needs to register for access only once before they can use the federated services. Single sign-on is increasingly implemented in the form of identity federations in both industry and academia.

Virtual Organisation Management & AAI

Within EGI, research communities are generally identified and, for the purpose of using EGI resources, managed through “Virtual Organisations” (VOs). Users are identified with X.509 certificates which are extended with VO attributes (e.g. acknowledging that the user is member of the VO) in a so called VOMS proxy. This VOMS proxy certificate is used in subsequent calls to the cloud endpoints which map the certificate and VO information each cloud management framework authentication and authorisation mechanisms via the integration modules for VOMS authentication. Configuring these modules into a provider’s cloud installation will allow members of these VOs to access the cloud.

Generic information about how to configure VOMS support for the supported Cloud Management Frameworks is available at MAN10. Information to how to add the support for a new Virtual Organisation on the EGI Federated Cloud can be found at HOWTO16.

EGI RC OLA expects every provider to support the following VOs:

The EGI Federated Cloud providers are also suggested to support the fedcloud.egi.eu VO, a catch-all VO that provides resources to users for a limited period of time (6 months initially) for protopying and validation.


OpenNebula Perun integration
rOCCI-server maps the certificate and VO information to local users. Local users need to have been created in advance, which is triggered by regular synchronizations of the OpenNebula installation with Perun.
Plugin for OpenStack Keystone to enable VOMS authentication. Allows users to get tokens which can be used to access any of the OpenStack services (including the OCCI interface). Users are generated on the fly in Keystone, it does not need regular synchronization with the VO Management server Perun.

IaaS Interfaces

Cloud systems must provide a set of interfaces through which users and user applications can interact with the services offered. In case of an IaaS cloud federation these interfaces offer compute, storage and network management capabilities. The interfaces can be harmonised across all participating cloud providers - in which case the providers are responsible for implementing the agreed standard - or can be native at the different sites. In this latter case, libraries or portals can hide heterogeneity from the users and can translate user requests to diverse native formats.



Federated IaaS Orchestration



EGI Federated promotes the use of open standards for providing a uniform interface and behaviour across different providers: OCCI for management of compute resources. The Federated Cloud APIs and SDKs page describes from a user point of view how these interfaces can be used.


The Open Cloud Computing Interface (OCCI) is a RESTful Protocol and API designed to facilitate interoperable access to, and query of, cloud-based resources across multiple resource providers and heterogeneous environments. The formal specification is maintained and actively worked on by OGF’s OCCI-WG.

The VM Management scenario page contains further details on the support for OCCI on different Cloud Management Stacks.


rOCCI - A Ruby OCCI Framework
Provides OCCI support for various Cloud Management Frameworks, including OpenNebula
OCCI for OpenStack Interface, provides OCCI support for the most recent versions of OpenStack
OpenStack OCCI interface, now deprecated.

OpenStack Compute

OpenStack sites of the EGI Federated Cloud can provide access through the native OpenStack API. The OpenStack API documentation is available at OpenStack developer pages. EGI Federated Cloud supports the usage of the Compute (nova) v2.1 API. The Federated Cloud APIs and SDKs page describes how to use this API in the EGI resources.

Virtual Machine Image Management

In a distributed, federated Cloud infrastructure, users will often face the situation of efficiently managing and distributing their VM Images across multiple resource providers. Users need a catalogue of Virtual Machine images (VMIs) that are usable on the IaaS cloud provider sites and encapsulate those software configurations that are useful and relevant for the given community. (Typically pre-configured scientific models and algorithms). To maximise usability of VMIs across cloud sites the images should be in a format that’s supported at every federation member site (Or at least can be converted to such formats). Users also need a system that automatically replicates VMIs from the VMI catalogue to the federation member sites, as well as removes them when needed. Automated replication can ensure consistency of capabilities across sites and is very often coupled with a VMI vetting process to ensure that only properly working, and relevant VMIs are replicated to the cloud sites of the community

AppDB Cloud MarketPlace

The EGI AppDB service has been extended to a Virtual Appliance Marketplace. This brings about a new category of software entries, called Virtual Appliances (VAs), which are, in all practical manners, clean-and mean virtual machine images designed to run on a virtualization platform, that provide a software solution out-of-the-box, ready to be used with minimal or no set-up needed within the EGI Federated Cloud infrastruture.

VM Image distribution

AppDB's Virtual Appliance Marketplace provides the ground for managing and publishing versioned repositories of virtual appliances using HEPiX image lists.

Research Communities ultimately create and update VM Images (or delegate this functionality). The Images themselves are stored in Appliance repositories that are provided and managed elsewhere, typically by the Research Community itself. A representative of the Research Community then generates a VM Image list (or updates an existing one) using AppDB user interface. Federated Clouds Resource Provider then subscribe to changes in VM Image lists by regularly downloading the list from AppDB, and comparing it against local copies. New and updated VM Images are downloaded from the appliance repository referenced in the VM Image list into a local staging cache and, where required, made available for further examination and assessment.

Ultimately, Cloud resource Providers will make VM Images available for immediate instantiation by the Research Community.


VMCaster / VMCatcher
VMCaster and VMCatcher allow creation and subscription of HEPiX image lists.
OpenNebula hook for VMCatcher
OpenStack handler for VMCatcher and python-glancepush
OpenStack hooks for VMCatcher

Service Registry

The Service Registry contains general information about the providers participating to the infrastructure and their capabilities. The registry provides the ‘big picture view’ about the federation for both human users and online services (such as service monitors).


EGI’s central service catalogue is used to catalogue the static information of the production infrastructure topology. The service is provided using the GOCDB tool that is developed and deployed within EGI. To allow Resource Providers to expose Cloud resources to the production infrastructure, a number of service types are available:

All providers must enter cloud service endpoints to GOCDB in order to enable integration with other operational tools.

Higher level broker services also have its own service types:

Further information about GOCDB can be find on the following page: GOCDB/Input System User Documentation.

Special rules apply for the following service types:


Endpoint URL field must contain the following info:



Endpoint URL field must contain the following info:


Both <image_name> and <resource_name> cannot contain spaces. These attributes map to os_tpl and resource_tpl respectively.


Endpoint URL field must contain Keystone URL (https://hostname:port/url) with the following additional info:


Both <image_name> and <flavour_name> cannot contain spaces.


Endpoint URL field must contain Keystone URL (https://hostname:port/url):


Information Discovery

The information system provides a real-time view about the actual capabilities and load of federation participants. The information system can be used by both human users and online services.

BDII and GlueSchema

Users and tools can discover the available resource in the infrastructure by querying EGI information discovery services. The common information system deployed at EGI is based on the Berkeley Database Information Index (BDII) with a hierarchical structure distributed over the whole infrastructure.

The information system is structured in three levels: the services publish their information (e.g. specific capabilities, total and available capacity or user community supported by the service) using an OGF recommended standard format, GLUE2. The information published by the services is collected by a Site-BDII, a service deployed in every site in EGI. The Site-BDIIs are queried by the Top-BDIIs - a national or regional located level of the hierarchy, which contain the information of all the site services available in the infrastructure and their services. NGIs usually provide an authoritative instance of Top-BDII, but every Top-BDII, if properly configured, should contain the same set of information.

Resource Providers must provide a Site-BDII endpoint that published information on the available resource following the GLUE2 schema. Even if the GLUE2 schema defines generic computing and storage entities, it was developed originally for Grid resources and can represent only partially the information needed by the Cloud users. Thus, the EGI Federated Cloud is working within the GLUE2 WG at OGF to profile and extend the schema to represent Cloud Computing, Storage and in the future Platform and Software services. The proposed extensions are currently under discussion at the WG. EGI provides an implementation for service-level information that generates information supporting OpenStack and OpenNebula, Synnefo support is currently being added. The information is published in a different subtree (Glue2GroupID=cloud) so it can coexist with grid information and is easily discoverable by users.

Information available for each provider:


Schema documentation TBC


Cloud BDII provider
Generates Glue 2 information by querying the Cloud Management Framework.


Federated Accounting provides an integrated view about resource/service usage: it pulls together usage information from the federated sites and services, integrates the data and presents them in such a way that both individual users as well as whole communities can monitor their own resource/service usage across the whole federation.

Usage Record

EGI Federated Cloud has agreed on a Cloud Usage Record -which inherits from the OGF Usage record- that defines the data that resource providers must send to EGI’s central Accounting repository.

Version 0.4 of the Cloud Accounting Usage Record was agreed at the FedCloud Face to Face in Amsterdam in January 2015. The definition with comments found here. A summary table of the format is shown below:

Cloud Usage Record Property Type Null Definition
VMUUID varchar(255) No Virtual Machine's Universally Unique Identifier concatenation of CurrentTime, SiteName and MachineName
SiteName varchar(255) No GOCDB SiteName - GOCDB now has cloud service types and a cloud-only site is allowed.
CloudComputeService (NEW) varchar(255) Name identifying cloud resource within the site. Allows multiple cloud resources within a site. i.e. a level of granularity.
MachineName varchar(255) No VM Id - the site name for the VM
LocalUserId varchar(255) Local user name
LocalGroupId varchar(255) Local group name
GlobalUserName varchar(255) Global identity of user (certificate DN)
FQAN varchar(255) Use if VOs part of authorization mechanism
Status varchar(255) Completion status - completed, started or suspended
StartTime datetime Must be set when Status = started
EndTime datetime Set to NULL until Status = completed
SuspendDuration datetime Set when Status = suspended (Timestamp)
WallDuration int WallClock time - actual time used
CpuDuration int CPU time consumed (Duration)
CpuCount int Number of CPUs allocated
NetworkType varchar(255) Needs clarifying
NetworkInbound int GB received
NetworkOutbound int GB sent
PublicIPCount (NEW) int Number of public IP addresses assigned to VM Not used
Memory int Memory allocated to the VM
Disk int Size in GB allocated to the VM
BenchmarkType (NEW) varchar(255) Name of benchmark used for normalization of times (eg HEPSPEC06)
Benchmark (NEW) Decimal Value of benchmark of VM using ServiceLevelType benchmark’
StorageRecordId varchar(255) Link to other associated storage record Need to check feasibility
ImageId varchar(255) Every image has a unique ID associated with it.
  • For images from the EGI FedCloud AppDB this should be VMCATCHER_EVENT_AD_MPURI
  • For images from other repositories it should be a vmcatcher equivalent
  • For local images - local identifier of the image
CloudType varchar(255) Type of cloud infrastructure: OpenNebula; OpenStack; Synnefo; etc.

APEL and accounting portal

Once generated, records are delivered via the network of EGI message brokers to the central accounting repository using APEL SSM (Secure STOMP Messenger) provided by STFC. SSM client packages can be obtained at https://apel.github.io. A Cloud Accounting Summary Usage Record has also been defined and summaries created on a daily basis from all the accounting records received from the Resource Providers are sent to the EGI Accounting Portal. The EGI Accounting Portal also runs SSM to receive these summaries and provides a web page displaying different views of the Cloud Accounting data received from the Resource Providers.


OpenNebula Accounting probe
OpenStack Accounting Probe

EGI A/R Monitoring

The participating providers may share certain operational tools and practices at the level of the federation, for example use a shared system to collect availability and reliability statistics about their site, or to share and respond to security alerts.

Services in the EGI infrastructure are monitored via ARGO. Specific probes to check functionality and availability of services must be provided by service developers, The current set of probes used for monitoring cloud resources consists of:

Probes for the image synchronization mechanism are currently under development. More information on cloud probes can be at Cloud SAM tests.

Currently a central instance specific to the activities of the EGI Federated Clouds Task has been deployed for monitoring test bed Results of cloud probes are visible on the central SAM interface under profile ch.cern.sam-CLOUD-MON and ch.cern.sam-CLOUD-MON_CRITICAL.

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