The benefits of cloud platforms over on-premises data centers are aplenty, but they introduce several risks enterprises must contend with. The increased scalability, improved performance and cost savings offered by the cloud are often overshadowed by governance challenges, data security threats and the need to comply with an increasing number of regulations.
In the following excerpt from Chapter 4 of CCSP Certified Cloud Security Professional All-in-One Exam Guide, Second Edition, published by McGraw Hill, author Daniel Carter, senior systems engineer at John Hopkins University, discusses the challenges that come with weighing the cloud's benefits to an enterprise business continuity and disaster recovery plan against the many risks it presents.
After reading the excerpt, be sure to take the CCSP exam questions to see what you have learned.
Disaster Recovery and Business Continuity Management Planning
A cloud environment represents a natural opportunity for a robust business continuity and disaster recovery (BCDR) program for any organization due to its constructs around resiliency, portability, interoperability, and elasticity. However, the cloud environment also presents its own unique challenges, as we will discuss next.
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Understanding the Cloud Environment
A cloud environment can be used for BCDR in a few different types of scenarios, such as hosting for either the primary or the BCDR site as a traditional data center or a cloud environment, or both environments being hosted in cloud environments.
The first scenario is where an organization has its primary computing and hosting capabilities in a traditional data center and uses the cloud to host its BCDR environment. This type of plan would typically revolve around already existing BCDR plans the organization has in place, where the cloud environment takes the place of the failover site should the need arise, versus having a BCDR site at another data center. This scenario leverages the on-demand and metered service aspects of a cloud platform, which makes it a very cost-effective method. With a traditional BCDR plan and a secondary data center, hardware must be procured and available for use, usually in a dedicated fashion, making costs significantly higher and requiring far more substantial prep time. Of course, as we discussed previously, extra care is required in going from a data center model to a cloud model to ensure that all security controls and requirements are being met, and there is no reliance on local security controls and configurations that cannot be easily duplicated or duplicated at all in a cloud environment.
Apart from the cost benefits of not having hardware standing by and ready at a BCDR site is the benefit of being able to test and configure without having staff onsite. Traditionally, BCDR tests involve staff traveling to the location to configure equipment, but in a cloud environment everything is done via network access. However, do not overlook the fact that in a real emergency, unless staff is geographically dispersed already, some travel may be required if network access is not available at the primary location.
A second scenario is where a system or application is already hosted in a cloud environment, and a separate additional cloud provider is used for the BCDR solution. This would be used in the case of a catastrophic failure at the primary cloud provider, causing the migration of all servers to the secondary cloud provider. This requires the Cloud Security Professional to fully analyze the secondary cloud environment to ensure it has the same or similar security capabilities to satisfy the risk tolerance of the company. Although the system and applications may be portable enough that they do not suffer from vendor lock-in and can easily move between different cloud environments, the secondary cloud environment may offer completely different security settings and controls from the primary environment. There is also the need to ensure that images from one cloud provider can be used by the other cloud provider, or there is additional complexity in preparing and maintaining two sets of images should a sudden disaster occur. As with any BCDR approach, there is the need to have data replicated between the two cloud providers so that the necessary pieces are ready in the event of a sudden disaster. Many times this can be implemented by using the secondary site to back up the primary site.
A third scenario is where an application is hosted in a cloud provider and another hosting model is used within the same cloud provider for BCDR. This is more prevalent with large public clouds that are often divided geographically because it provides resiliency from an outage at one data center of the cloud provider. This setup certainly streamlines configuration and minimizes configuration difficulties for the customer, because both locations within the same cloud provider will have identical configurations, offerings, options, and requirements. This differs in regard to having a BCDR configuration between different cloud providers or data centers in that vendor lock-in is not a prevailing concern.
Understanding Business Requirements
Three big concepts are crucial to determining the business requirements for BCDR, whether implemented with a traditional data center model or a cloud hosting model:
- Recovery point objective (RPO) The RPO is defined as the amount of data a company would need to maintain and recover in order to function at a level acceptable to management. This may or may not be a restoration to full operating capacity, depending on what management deems as crucial and essential.
- Recovery time objective (RTO) The RTO is a measurement of the amount of time it would take to recover operations in the event of a disaster to the point where management's objectives for BCDR are met.
- Recovery service level (RSL) The RSL measures the percentage of the total, typical production service level that needs to be restored to meet BCDR objectives in the case of a failure.
Be sure to know the difference between these three concepts and to recognize them by their acronyms.
These three measures are all crucial in making a decision as to what needs to be covered under the BCDR strategy, as well as the approach to take when considering possible BCDR solutions. The prevailing strategy for any company will constitute a cost–benefit analysis between the impact of downtime on business operations or reputation versus the costs of implementing a BCDR solution and to what extent it is done.
Management first needs to determine the appropriate values for RPO and RTO. This step serves as the framework and guidelines for the IT staff and security staff to begin forming a BCDR implementation strategy. These calculations and determinations are completely removed from the possible BCDR solutions and are made strictly from the business requirement and risk tolerance perspectives.
Once management has analyzed and assigned requirements for the RPO and RTO, the organization can set about determining which BCDR solutions are appropriate to meet its needs, weighed against cost and feasibility. While this entire analysis is agnostic of the actual solution, there are some key aspects of cloud computing, spanning multiple areas of concern, that need to be addressed.
A primary concern when it comes to BCDR solutions in the cloud goes back to two main regulatory concerns with cloud hosting in general -- where the data is housed and the local laws and jurisdictions that apply to it. This can be a particular concern for those opting for a model with a traditional data center and then using a cloud provider for their BCDR solution, where they are moving into an entirely different paradigm than their production configurations and expectations. However, it also plays prominently in the other two scenarios, because even within the same cloud provider, the other data centers will be in different geographic locations and possibly susceptible to different jurisdictions and regulations, and the same holds true for using a different cloud provider.
With any BCDR plan, there are two sets of risks -- those that require the execution of the plan in the first place, and those that are realized as a result of the plan itself.
Many risks could require the execution of the BCDR plan, regardless of the particular solution the company has opted to take. These risks include the following:
- Natural disasters (earthquakes, hurricanes, tornadoes, floods, and so on)
- Terrorists attacks, acts of war, or purposeful damage
- Equipment failures
- Utility disruptions and failures
- Data center or service provider failures or neglect
Apart from the risks than can lead to the initiation of a BCDR plan, there are also risks associated with the plan that need to be considered and understood:
- Change in location Although cloud services are normally accessed over broad networking, a change in geographic hosting location in a BCDR situation can cause network latency or other performance issues. This can impact both the user and customer perspectives when it comes to the system or application, as well as the business owner's ability to update and maintain data, especially if large data updates or transfers are required. Latency can also implement timing issues between servers and clients, especially with many security and encryption systems that rely heavily on time syncing to ensure validity or timeout processes.
- Maintaining redundancy With any BCDR plan, a second location will need to be maintained to some extent, depending on the model used and the status and design of the failover site. Both sites will need additional staffing and oversight to ensure they are compatible and maintained to the same level in the event an unforeseen emergency happens without notice.
- Failover mechanism In order for a seamless transition to occur between the primary and failover sites, there must be a mechanism in place to facilitate the transfer of services and connectivity to the failover site. This can be done through networking changes, DNS changes, global load balancers, and a variety of other approaches. The mechanism used can involve caching and timeouts that impact the transition period between sites.
- Bringing services online Whenever a BCDR situation is declared, a primary issue or concern is the speed at which services can be brought online and made ready at the failover site. With a cloud solution, this typically will be quicker than in a traditional failover site because a cloud provider can take advantage of rapid elasticity and self-service models. If the images and data are properly maintained at the failover site, services online can brought quickly.
A common practice is to leave images offline at the BCDR site when not in use. This can cause major problems in the event of a BCDR situation if the system images are not patched and up to date with configurations and baselines for the production systems. If the images are to remain largely offline, the Cloud Security Professional will need to ensure that appropriate processes and verifications are in place with images at the BCDR site.
- Functionality with external services Many modern web applications rely on extensive web service calls out to other applications and services. With a BCDR situation, a crucial concern is ensuring that all hooks and APIs are accessible from the failover site in the same manner and at the same speed as they are with the primary location. If there are keys and licensing requirements to access services from the application, those also must be replicated and made ready at the failover site. If the service has checks in place for the origination of IP addresses or some other tie into actual hosts and locations, the company will need to ensure that the same service can be accessed from the failover site with whatever information necessary already available and configured. Although the failover cloud site may have on-demand and self-service capabilities, it is likely that any external tie-ins will not have the same capabilities and will cause complications while the staff is trying to get their own services up and running.