Today's cloud orchestration software systems all have a horizontal tight coupled architecture. As a result today's clouds do not scale. DaoliCloud proposes a new architecture for cloud orchestration to horizontally decouple cloud orchestration. The new architecture is enabled by a novel formulation in SDN forward plane. The work not only eases and lowers cost for cloud deployment, operation and maintenance, but also has a potential for future inter-cloud work.

1. Horizontal Decoupling of Cloud Orchestration for Stabilizing Cloud
Operation and Maintenance
Wenbo Mao
DaoliCloud Company
Beijing and Shanghai, China
www.daolicloud.com
February 8, 2015
In a plain and understandable desire for achieving economies of scale, a cloud
orchestration software system should be capable of managing a huge farm of hardware
servers. However, even using most advanced software configuration and management
tools, the field has trial-and-error reached a common sense that the distribution scale of
a cloud orchestrator mustn’t be too large. E.g., VMware, probably among the most
experienced players in the trade, stipulates a rule-of-thumb upper bound for its
orchestrator vRealize: No more than 1,000 servers per vRealize even if the software is
installed on top quality hardware devices. Scaling-up beyond that level, cloud operation

2. and maintenance would become unstable plus incur sharp cost increasements in
operation and maintenance. Recent achievements in hyper efficient CPU virtualization
by Docker have seminally ignited additional orders-of-magnitude explosions in the
number of micro-servicing CPUs, certainly to add further troubles to worsening
scalability in cloud orchestration. Current poor scalability status quo in cloud
orchestration means that today’s clouds are in small isolated scatters and patches, and
therefore cannot efficiently tap cloud potentials from economies of scale.
The essential problem behind poor scalability in cloud orchestration is that all cloud
orchestrators, from commercial offerings or from open source projects, unanimously
and conventionally evolve from a horizontally tight coupled architecture. A horizontally
tight coupled orchestrator is a bunch of software components which are host knowledge
interwoven. By speaking of "host knowledge interwoven", we mean that the
software components in a cloud orchestrator know the existence, roles and duties of
one another right at their birthday of being installed on a farm of server hosts, and
throughout their remainder entire lifecycles afterwards. When a farm gets large, some
queues of events and messages will inevitably become long; writelock mechanisms
for consistency protection and CoW DB accesses will also aggregate momentum to
slow down responsiveness; and occasional unfortunate popup of failures, even merely
in a benign timeout sense, occurring at one point in the farm would highly likely pull
down other knowledge interwoven parts. As a matter of fact, all cloud servicing or
hosting providers, as long as having a size, all have to rely on human based
operation/maintenance teams 7x24 on-guard the farm, playing similar roles of
firefighters!
We present Network Virtualization Infrastructure (NVI) technology to horizontally
decouple cloud orchestration. The NVI technology minimizes the size of a cloud
orchestration region down to over one single hardware server, e.g., in the formulation of
OpenStack all-in-one installation. An orchestrator managing only one server host of
course has absolutely no knowledge whatsoever about any other orchestrator
managing another server. Thus, any server host in an NVI farm has no software
knowledge about any other server host in the farm. While having obviously maximized
stability for cloud operation and maintenance, the overlay cloud resources which are
pooled by NVI remain to have unbound scalability. This is because NVI can trans-
orchestrator connect overlay nodes in user mode only upon one node initiating
communication to another (think of http connection!). NVI can connect various virtual
CPUs over independent and heterogeneous cloud orchestrators, e.g., connect
lightweight micro-servicing Docker containers and heavy-duty hypervisor VMs, which
are independently orchestrated by, e.g., Kubernetes and OpenStack. Moreover,
NVI can transparently link different cloud service providers, also in user mode.
The key enabler for any two not-knowing-one-another orchestrators to serve user-mode
connection for their respectively orchestrated overlay nodes is a novel OpenFlow
formulation for forwarding trans-orchestrator underlay packets. This new SDN

3. formulation succeeds constructing any OSI layer, any form of overlay network without
any need of packet encapsulation, i.e., without using any of the trans-host-network
protocols such as VLAN, VXLAN, VPN, MPLS, GRE, NVGRE, LISP, STT, Geneve, or
any such we may have missed from the enumeration! Having avoided trans-host packet
encapsulation, there is of course no need for the involving orchestrators to know one
another in host mode, neither in the system installation time nor in their remainder entire
lifecycles afterwards. It is in such a simple principle that the SDN innovation of NVI
achieves complete horizontal decoupling of cloud orchestration. With connection taking
place only in user mode, cloud deployment, operation, maintenance, and system
upgrading, etc., can become 100% automated. It is now also plainly manifested that the
NVI technology supports inter-cloud patching, also in user mode.
With the problem-solving architecture of NVI for truly scalable cloud
orchestration, DaoliCloud attempts to contribute to the cloud industry a new production
line: “Build, ship and low-cost operate any cloud, any scale”, as a new frontier to work
with, extending from the great inspiration of “Build, ship and run any app, anywhere”
from Docker. Having fixed a single small size for orchestrator installation and
configuration, build, ship, operate and maintain any cloud, private or public, will be low
cost, and fast because of one size and automation.
URL http://www.daolicloud.com exposits, in "for dummies" simplicity, a near-product-
quality prototype of our new cloud orchestration technology which horizontally
decouples globally located orchestrators. These globally distributed, host-mode not-
knowing-each-other, and user-mode well organized orchestrators are independent all-
in-one OpenStack hosts in Beijing, Shanghai and N. Virginia. We cordially invite much
respected reviewers of this abstract, and hopefully many subsequent interested trial
users in the audience of the forthcoming OpenStack Summit, to signup on the above
URL for a trial use. We humbly wish that some trial users might come to an appreciation
that the new architecture work for scalable cloud orchestration can indeed enable a
number of never-known-before useful cloud properties which are probably only made
possible from the new architectural innovation in cloud orchestration as a
specific application, and in network virtualization for a more
general pursuit in knowledge and technology advances.