Chapter 2. Planning the implementation and architecture of a virtualized B
2.2 Cloud architecture
By now, the business benefits gained by adopting cloud technologies should be clear, as is the process of implementing a basic cloud solution. But to fully understand the potential technical benefits of the cloud approach, the
architecture of a cloud must be examined in detail. Knowing the different types of cloud deployments will help you select the correct one for your enterprise. This section describes the architecture and components of each type of cloud: Public cloud
Private cloud Hybrid cloud
2.2.1 Public cloud
Public cloud infrastructure uses many different IT resources. These resources are often delivered by third-party vendors over virtualized platforms, meaning specific network infrastructure, hard disk, memory, and other requirements with respect to manufacturers and peripherals cannot be customized.
Figure 2-6 shows an example of a public cloud architecture.
Figure 2-6 Sample cloud infrastructure
A public cloud includes the following typical components: Server instances
Stand-alone virtualized server instances that provide a bare-bones computing solution. Usually, server instances come with different computing capacities to suit differing technical needs, allowing for customization of CPU, memory, and storage.
Server instances come with a pre-installed operating system, which is usually also customizable. Server instances can be started, stopped, and discarded as necessary to maximize resource efficiency and save on costs. Multiple server instances can be launched within the same zone to reduce network latency between co-located servers.
Storage
Although base storage is usually provided in a cloud’s server instance, there can be times when additional storage is needed. This additional storage, unlike the base server instance storage, is usually customizable in terms of size and performance. It is advantageous in other ways, too, because server instances are often seen as volatile (non-resilient), which makes data on auxiliary storage more persistent. Auxilary storage is often replicated across several data centers in different locations, which provides data redundancy and makes auxiliary storage ideal for storing backups and for keeping costs low when server instances are shut down or discarded.
Networking
Public cloud vendors often have multiple data centers in the same region that are interconnected by a high-speed LAN. However, to achieve redundancy, there can be multiple regions in the same zone, and therefore latency between regions can be slightly more significant than it is within a single region. Vendors often provide premium network hardware options for premium cloud server offerings.
Other infrastructure resources
Public cloud vendors usually offer a number of other resources to supplement the infrastructure backbone, such as services that improve security,
resilience, monitoring, load-balancing, and so on. Examples of such
resources and services include cloud VPNs, firewalls, and dedicated network options such as static IP addresses.
Platform-as-a-service
Many public cloud vendors offer a variety of different platform-as-a-service (PaaS) options, ranging from middleware software and databases to
complete development environments, application lifecycle management, and web servers.
Cloud API and Web UI
A web console is commonly employed to facilitate fundamental operations within a cloud computing environment. The web console serves as a central hub for managing and monitoring the cloud resources. To automate and templatize the launching of resources and services, a cloud API can be used. Note that because a public cloud is still a maturing technology, standardized APIs do not yet exist among the different public cloud vendors. Therefore, care must be taken in deciding which public cloud vendor can best fulfill your cloud solution requirements.
At a minimum, an effective UI console and API performs these tasks: – Provisioning and management of server instances and other resources – Client billing and metering
– Image cataloging
– Cloud infrastructure monitoring – Account management
Figure 2-7 shows these and other important features of an effective cloud computing solution.
Figure 2-7 Features of an effective cloud solution
IBM middleware is cloud-ready on multiple public cloud platforms that are available today. Pre-installed images for some of today’s most popular cloud platforms can be integrated into an existing solution, thereby reducing time-to-value. Here is a list of cloud vendors that host IBM middleware: IBM SmartCloud Enterprise
– Enterprise-focused
– Largest pre-existing library of IBM software cloud images – Data centers in North America, Europe, and Asia
– Instance sizing to suit any hardware requirement
For clients interested in private cloud deployment, IBM also offers SmartCloud Enterprise+, an IBM-managed IaaS cloud.
IBM SmartCloud services can be divided into application services, enterprise services, and enterprise+ services, as shown in Figure 2-8.
Figure 2-8 IBM SmartCloud infrastructure and platform services
Amazon Web Services Elastic Compute Cloud
– Pre-bundled IBM software cloud images available since February 2009 – Flexible payment options including pay-as-you-go by-the-hour billing, or
you can use your own IBM middleware license
– Most widely used and mature public cloud platform available today – Offers the most advanced technical features including VPNs, segregated
data zones and centers for redundancy, static IP addressing, load-balancing and storage
– Highest degree of geographical accessibility with data centers spread across the globe
GoGrid cloud
– ISV-focused, with easy to build on pre-built images to speed new offerings to market; GoGrid handles the billing
– Dynamically resizable instance capacity
– Hardware VLAN for network segregation, dedicated firewall options, available VPN, and user-friendly API
– Offers both by-the-hour and subscription-based servers, plus hybrid solutions
– Large library of available software images – Data centers in North America and Europe
– GoGrid Exchange area to showcase your offerings
All of the public cloud vendors listed here offer many options and configurations for hardware to meet a wide range of requirements for CPU, storage, networking, security, and accessibility.
2.2.2 Private cloud
A particular advantage of implementing a private cloud solution is the ability to choose and customize any component within the solution. Components suitable for customization include the following:
Hardware
Choosing the correct middleware components for a BI cloud solution is imperative for a successful deployment. Is the identified middleware cloud-ready? Do the middleware components support the requirements for scalability, virtualization, varying workload sizes, security, and performance? Support software
These components glue together the various pieces of your BI cloud solution. For example, consider what operating system to use and its support for various software packages. What software and services are required to maintain things such as time, availability, web server, LDAP, and DNS services.
Client software
This software or service is the client’s specialization. It can be anything from optimizing performance to adding new capabilities to existing middleware components. This is the added value that customers ultimately seek in a truly innovative BI cloud solution. Consider how this software is accessed today. Is it already software-as-a-service ready, or does it require additional
Virtualization technology
What are the requirements for virtualization? Virtualization enables multiple working environments to be created from a single physical computing environment. Good virtualization software provides a cloud solution with abilities such as multi-tenancy, scalability, isolation, high availability, monitoring, improved efficiency, and more. Consider which middleware components and services require virtualization. Some of them are obvious candidates to be virtualized but others require too high a level of performance to perform virtually. For example, if specific software requires high network connectivity that virtualized hardware cannot provide, then it might need to be hosted by physical infrastructure instead. There are many virtualization options available today, including VMware, KVM, and Xen virtualization, each with their own unique features and advantages.
2.2.3 Hybrid cloud
A