Load Balancing in the Cloud (with Diamonds)
Load balancing technologies are still needed when businesses put their applications in the cloud. One of the primary reasons people are putting their applications in the cloud is because they want the applications available anytime and anywhere.
The cloud infrastructures are designed to provide a unified service that makes their applications available without having to understand or deploy many of the complex technologies that provide application availability and resiliency.
Unfortunately, most cloud services do not deliver the advanced capabilities necessary so that applications are available under all fault scenarios. Applications must reside on specific server instances within the cloud infrastructure. If the hardware or software for that server instance fails, then the application is no longer accessible. Also, if the cloud provider has broader internet connectivity issues, then the clients will not be able to reach the application.
Elasticity through load balancing
Traditional load balancing technologies can mitigate these problems with application accessibility in the cloud. Multiple virtual instances of the application in the cloud can be load balanced using proven and mature server load balancing (SLB) technologies.
SLB can pool multiple instances of the same application to provide resiliency in case one or more of the virtual servers fails due to hardware or software malfunction. SLB also delivers scalability by allowing clients to connect to a single address and distributing the connections across the multiple application servers.
Resiliency through cloud redundancy
Global server load balancing (GSLB) offers a solution when the cloud provider is having broad connectivity issues. Traditionally, GSLB is used to provide dynamic failover between different data centers through the use of dynamic DNS responses.
When applications are moved to the cloud, a public cloud provider can be seen to be like a single data center. Businesses need a diverse solution that utilizes a combination of private data centers and multiple public cloud providers to ensure that their applications are always available. Public clouds can have outages just like any other data center architecture.
For the mission critical applications, businesses need to ensure that there are multiple ways to access the application. This eliminates any single point of failure that can cause the entire application to become unavailable.
Value add through mature and advanced technologies
Load balancing technologies have been around for 20 years. They are proven and stable. Cloud architectures are valuable by creating a more flexible application infrastructure, but they are only one of the available tools that businesses must leverage. The combination of load balancing technologies with cloud architectures creates a complete architectural solution that ensures application availability, scalability, and resiliency that is required for any mission critical application.