Exploring Quality of Service (QoS) Contracts
In this lesson, we will explore the Quality of Service contracts and types of QoS classes.
Understanding the Scheduling Process
When we send a request to Kubernetes API to create a Pod (directly or through one of the Controllers), it initiates the scheduling process. What happens next or, to be more precise, where it will decide to run a Pod, depends hugely on the resources we defined for the containers that form the Pod. In a nutshell, Kubernetes will decide to deploy a Pod, whenever it is possible, inside one of the nodes that has enough available memory.
Memory Requests and Limits
When memory requests are defined, Pods will get the memory they requested. If the memory usage of one of the containers exceeds the requested amount, or if some other Pod needs that memory, the Pod hosting it might be killed. Please note that we wrote that a Pod might be killed. Whether that will happen depends on the requests from other Pods and the available memory in the cluster. On the other hand, containers that exceed their memory limits are always ...