CloudFormation(Amazon, 2016), Rightscale Cloud
Management Platform(Rightscale, 2016), RedHat
CloudForms(RedHat, 2016), IBM Cloud Orchestra-
tor(IBM, 2016)). The most advanced platforms also
offer services and tools for the management of cloud
applications’ lifecycle. None of these commercial
products are open to the community, nor the solutions
they offer are portable across third-party providers.
As to open-source Cloud orchestration frame-
works, the OpenStack platform
1
includes an Orches-
tration service which provides a template-based way
to describe a cloud application based on TOSCA. The
templates, written according to the HOT (Heat Or-
chestration Template) template language
2
, enable to
create most OpenStack resource types, such as in-
stances, storage volumes, networking information, se-
curity policies, and all the other required cloud infras-
tructure to run an application. Another notable ex-
ample of orchestration platform in the open source
domain is Cloudify(GigaSpaces, 2016): it allows to
model applications and automate their entire lifecycle
through a set of built-in workflows.
Some minor research initiatives have come up
with open source solutions as well. Roboconf (Pham
et al., 2015) is an open sourced hybrid cloud or-
chestrator for application deployment. It implements
the basic administration mechanisms which are called
Autonomic Computing Systems (ACS). Roboconf
has simple and extensible design, many of its com-
ponents are reusable. A Domain Specific Language
(DSL) is also presented for fine-grain definition of
applications and execution environments. Their re-
search has tended to focus on installation and con-
figuration of applications rather than addressing the
management issues of hybrid and multi-clouds.
With respect to standardizing initiatives, OASIS
is the most active on the cloud provisioning topic.
TOSCA, which stands for Topology and Orchestra-
tion Specification for Cloud Applications, is a stan-
dard designed by OASIS to enable the portability of
cloud applications and the related IT services (OA-
SIS, 2013). This specification permits to describe
the structure of a cloud application as a service tem-
plate, that is in turn composed of a topology_template
and the types needed to build such a template. The
TOSCA Simple Profile (OASIS, 2017) is an isomor-
phic rendering of a subset of the TOSCA v1.0 XML
specification in the YAML language. It provides a
more accessible syntax as well as a more concise and
incremental expressiveness of the TOSCA language
in order to speed up the adoption of TOSCA to de-
scribe portable cloud applications.
1
www.openstack.org
2
https://wiki.openstack.org/wiki/Heat
A couple of initiatives regarding the use of poli-
cies to support the deployment of cloud application
are worth to be cited. A scheduling method based
on SLA metrics for deploying application in cloud
(Emeakaroha et al., 2011) is discussed. This method
takes into account the amount of required CPU, net-
work bandwidth and storage. The resource with con-
strained SLA in IaaS, Platform as a Service (PaaS),
Software as a Service (SaaS) is provided by the
scheduling method. This research outlines a novel as-
pect of application deployment in cloud. In the paper,
the resources are differentiated only by the metrics of
SLA. However, in enterprise hybrid cloud there are
far more parameters which need to be considered to
classify a cloud resource. Similarly, a cost based dat-
acenter resource decision model (Strebel and Stage,
2010) is proposed for application deployment in hy-
brid cloud. It builds optimization model to com-
pare virtual machines’ tariffs to achieve economic ef-
ficiency of application operation. A major limitation
of this research is that it takes only one factor into
account the cloud resource selection in hybrid cloud.
3 SYSTEM ARCHITECTURE
For the enterprise that owns or uses a large scale IT
infrastructure with multi-clouds, the common practice
is to divide the infrastructure into several independent
infrastructure domains based on business and IT re-
quirements. For example, a global multi-clouds in-
frastructure can be divided into two management do-
mains, because it owns two data centers in two differ-
ent locations (e.g., one in Frankfurt and one in Paris).
Should private resources be insufficient to sustain the
enterprise’s business growth, publicly provided re-
sources come to the aid (Amazon AWS
3
, Microsoft
Azure
4
, etc.). The depicted scenario can become very
problematic to manage, as it includes the presence of
hybrid and geographically distributed resources. Is-
sues can arise from both the technical point of view
(different APIs to access resources provided by third
parties) and the administrative point of view (different
law restrictions on data enforced by countries, hetero-
geneous security and SLA guarantees offered by third
parties).
The complexity of multi-domain infrastructures
can be faced with the help of policies. A policy ap-
plies to a specific context and defines a set of pos-
sible actions that can be triggered according to the
activation of given rules. So, for instance, a policy
3
aws.amazon.com
4
azure.microsoft.com
Policy-based Deployment in a Hybrid and Multicloud Environment
389