EAI Options - From On-Premise to In-The-Cloud

• Posted by ErikW on March 31, 2009
• 0 comments

My last post discussed integration in terms of the problems that integration addresses along with the major patterns that are used to implement integration solutions.

Seemingly ordinary decisions about integration solutions can turn out to have significant impact on your integration solution’s capabilities and day-to-day operations. One of those decisions is where you plan to host your integration solution and the applications that your solution integrates. There are several options available: on-premise, off-premise, and cloud hosted solutions. The list of options expands when you add self-managed and managed hosting, as well as application versus compute cloud-based variations to the hosting models.

This article describes each type of hosting model using a brief description, when it’s used, and its benefits and drawbacks.

On-Premise Hosting

On-premise hosting is probably the most common hosting model for most medium-sized businesses (those that have about 150 to 500 employees). Small and large organizations that currently host their applications on-site are starting to move towards some type of off-premise hosting due to its lower cost and flexible deployment options.

Since most organizations that use software are not in the information technology business, on-premise hosting usually involves housing a few server computers in a dedicated office, or in some closet, and having a dedicated ‘IT guy’ manage the servers and applications they run. This model works because it is simple: an organization can grow the model organically (expand the number of servers and hire a dedicated person as the organization grows).

An alternate on-premise hosting model is called managed on-site hosting. Managed on-site hosting improves on un-managed on-site hosting by moving servers into a more appropriate space (usually a temperature and access-controlled server room) and outsourcing management of the servers and their applications to a third party. The third party is usually an organization that specializes in server management so they often include capabilities like remote management, 24-hour per day monitoring, service level agreements, and other management capabilities.

Benefits Include:

• Ease of expansion – add servers and IT staff as your organization grows.
• Ease of management – all hardware is co-located with the organization making it easy to restart servers or take backups.

Drawbacks include:

• Poor flexibility for changing demands: Expensive and slow to adapt to changing demand (seasonal work loads, for example). Expenditures include excess capacity to handle occasional loads.
• High-upfront cost: expenditures include server hardware and software licenses
• High on-going maintenance costs: whether managed by IT staff or by a third party, maintenance can get expensive when vendors release major updates or new versions of software. Hardware upgrades can be expensive too.

Off-premise Hosting

Off-premise hosting is growing in popularity because it offers much more flexibility than on-premise hosting, with better reliability and at a lower cost.

While there are several variants of off-premise hosting, all share some common traits based on the hosting provider’s services. They include:

• 24 hour per day monitoring and response
• Managed software upgrades
• Service Level Agreements
• Reliable backups
• Access and temperature controlled conditions
• Fail over capability in case of disaster
• Managed hardware upgrades and maintenance
• Reliable network connectivity
• Secure remote management capabilities

Off-premise hosting providers offer a leveraged environment – this means that the hosting provider offers services to many clients using a common infrastructure. As a result, hosting providers offer a range of services at a price that is often lower than managing those same services on your own in an on-premise model.

There are two variants of off-premise hosting:

• Shared hosting: your organization’s application needs are common enough to be deployed on a large server that’s shared by several organizations. This approach is sometimes referred to as the tenant model.
• Dedicated hosting: your organization either deploys its own servers or uses the hosting provider’s servers. The servers are not shared, therefore, they are dedicated to your organization’s applications.

Off-premise hosting often requires long-term, contractual commitments for both parties as well.

Benefits include:

• Low up-front costs: the hosting provider usually buys and manages physical server computers and may also buy and manage software licenses.
• Leveraged infrastructure: hosting providers usually have high-quality, reliable, secure infrastructures that provide backup power, redundant connectivity and other options, often included as standard features.
• Insulation from staff turnover: the hosting provider handles training of their own staff thereby insulating your organization from staffing changes. This results in a more consistent service level.

Drawbacks include:

• Slower deployments: adding or changing hardware or software is managed, which is slower than simply walking up to a server and putting a CD into the CD drive.
• Change management: organizations need to plan changes in advance and may require review and approval by the hosting provider.
• Long-term contracts: organizations may not want, or be able to commit to multi-year contracts.
• Overhead of handover: hosting providers usually require training for specialized applications or management needs. This can add overhead or may require sharing of confidential information.

Cloud-based Hosting

Cloud based hosting has been in broad use for about a year, and is gaining fast acceptance by all types of organizations, primarily due to the billing model and flexibility.

The cloud hosting providers essentially offer CPU time, memory, disk space, and network connectivity as a service, on an on-demand basis. The term ‘cloud’ is based on a term that describes an abstraction over a complex infrastructure.

There are two variations of cloud-computing:

• Virtual Servers: your provision and configure your own virtual server by installing applications and managing updates, etc
• Application Hosting: the hosting provider directly hosts and manages your applications, so that you are unaware of, or care about the underlying system.

The choice about which variant you use depends on your application’s needs. Web-based applications are excellent candidates for application hosting since the hosting provider can add and remove computing capacity based on the needs of the application. Virtual Servers are an excellent choice for specialized applications that require flexible software environments.


Benefits of cloud computing include:

• Activity-based billing: you pay only for the computing, storage, and network traffic your application(s) uses.
• Ease of deployment: provisioning a new server often involves making a few choices when filling in a form on a web page, then waiting for a few minutes for the server to start.
• Ease of scalability: adding compute resources is often a simple matter of shutting down your server and restarting it using another configuration making it easy to respond to changing demands or loads.
• Managed infrastructure and software: the hosting provider offers a leveraged infrastructure and often offers licensed operating systems and applications.

Drawbacks of cloud computing:

• Little or no control over where servers and data are deployed.
• Internet based infrastructure: all traffic between your organization and the hosted solution travels over the public internet (the traffic can, however, be secured).
• Centralized model: when the hosting provider experiences an outage, it often affects many of the provider’s clients.
• Early stage of deployment: lack of standards across hosting providers, changing features and service offerings.

Conclusion

Seemingly ordinary decisions about integration solutions can turn out to have significant impact on your integration solution’s capabilities and day-to-day operations. Planning your application’s hosting model in advance results in a more responsive infrastructure at an appropriate cost.

Of all the hosting models, cloud computing is growing the fastest, primarily as a result of it’s flexibility and attractive pricing model.

TechBlocks’s EAI practice is experienced in developing, deploying, managing, and maintaining applications using all of the hosting models described in this article. From on-premise, to Micosoft Azure and Amazon’s EC2 cloud offerings, we offer flexible, reliable solutions to your organization’s integration needs. Contact us today.

About the author: Erik Westermann is an EAI expert, working with technologies like Microsoft’s BizTalk Server. Erik provides training, mentoring, architecture and software development services, specializing in service oriented, scalable, and secure solutions using Microsoft and other technologies. Erik also publishes an EAI magazine at ArtOfBabel.com.

Contact Erik Westermann today via TechBlocks to discuss your integration needs (http://www.tblocks.com/BLOG/contact.aspx).