Hybrid Cloud Apps with OpenShift and Kubernetes

Chapter 4. Single Cluster Availability

A solid foundation for each individual cluster is critical to the availability of your applications and services. Even with these advanced distributed application capabilities, there are some systems for which multicluster isn’t an option. Most stateful applications and databases are not capable of geographic distribution and are very complicated to properly operate across multiple clusters. Many modern data storage solutions require low latency multizone solutions, making it less than optimal to break up the data clusters into higher latency environments. It is also important to consider that many data platforms have StatefulSet solutions to help operate them, requiring a single-cluster architecture. We think that having a strong foundation of what it means for a system to be available and highly available is critical to understanding the value and architecture of OpenShift and Kubernetes. Note that we’ll discuss how to take advantage of multicluster architectures for the ultimate in availability and flexibility in Chapter 5. This chapter should help prepare you with the knowledge required to make intelligent decisions about what your availability goals are and how to leverage Kubernetes and OpenShift to achieve them.

System Availability

In modern service and application delivery, we typically talk about system availability in terms of what percentage of time an application or service is available and responding normally. A common standard ...