The cloud embodies the idea of having access to the information that you need anytime and anywhere. Availability are closely related. The cloud gives companies the ability to have an office without a physical office. People can work remotely from anywhere around the world using cloud technology. However, if the service continually goes down, then the cloud is useless. The cloud must be up 24 X 7, which means building machines that can offer this type of reliability (Rodrigues, 2011).
If the cloud goes down, then the global network is suddenly only a local network. Local networks no longer have access to global information. They are isolated. Redundancy using a series of failover servers is the usual method for achieving this type of reliability. In 2011, Amazon’s EC2 service suffered and 11-hour outage (Rodrigues, 2011). This not only affected Amazon, it affected all of its sellers too.
Cloud based services rely on the interaction between many different components. A problem in any one of the components can compromise the entire system. With each increase in complexity, the potential for a failure increases (Rodrigues, 2011). One of the advantages of a cloud based system is that there are often overlaps and redundancies in servers. This means that if one server goes down, another will be up and ready to pick up the slack.
When building a cloud based network four steps are recommended to achieve high availability. The first is to build for server failure (Adler, 2012). This means using database mirroring, master/slave configurations, dynamic DNS, and static IPs so that the various encapsulated components have the right context (Adler, 2012). Building for zone failure is the next step. This means spreading servers in application tiers across two or more zones. It means replication of data across zones (Adler, 2012). One should also build for regional cloud failure. This means building architecture that has uniform configurations (Adler, 2012). The fourth step is to automate and test everything (Adler, 2012). These four principles will help to maintain availability, even in the event of a failure on any level.
High availability using a cloud based network shifts some of the responsibility for security from the operator to the client organization (IBM Global Technology Services, 2011). Cloud based systems means that members of different organizations and members with different access levels interact on the same hardware and software. This presents more opportunities for data compromise, misconfiguration, and malicious conduct (IBM Global Technology Services, 2011). This means that a local network faces a higher level of vulnerability when working in the cloud due to the exposure level of its resources.
Shared environments mean shared responsibility on all levels of the network. There is a shared responsibility to build redundancy into the system. There is a shared responsibility to keep the system safe from attack, and there is a shared responsibility for management and the ability to provide high availability to the users for the data that they need on their local network. Identity control and access are challenging in a cloud environment. High availability means redundancy that stretches across zones and provides redundancy on a regional basis as well. The cloud based network must be able to handle fluctuating loads and be able to maintain service in a reliable way.
The cloud based environment has an effect on the local network and the local network can also have effect on the cloud services through the data that it transmits. This creates a two-way interconnection between the global environment and the cloud environment. This interconnection has the ability to run a local network into a global network. The local network inherits the advantages of the data availability, but it also inherits the risks that are associated with greater exposure to vulnerabilities. The job of a cloud based network administrator is to balance the benefits and risks in a way that creates the highest availability possible.
- Adler, B. (2012). Four Steps to Achieving High Availability in the Cloud. Right Scale. Retrieved
from
http://www.rightscale.com/blog/enterprise-cloud-strategies/four-steps-achieving-
high-availability-cloud - IBM Global Technology Services. (2011). Security and high availability in cloud computing
environments. Retrieved from http://www-
935.ibm.com/services/za/gts/cloud/Security_and_high_availability_in_cloud_computing_
environments.pdf - Rodrigues, T. (2011). What high availability for cloud services means in the real world.
TechRepublic. Retrieved from http://www.techrepublic.com/blog/the-enterprise-
cloud/what-high-availability-for-cloud-services-means-in-the-real-world/
