148422597X Kubernetes Management Design Patterns [Vohra 2017-01-29] {E559F6BB}

Types of Compute Resources
Chapter 10 ■ Configuring Compute Resources
Kubernetes provides two types of compute resources, CPUs and memory, as shown in Figure 10-3.
Compute Resources
CPUs
Memory
Figure 10-3. Types of compute resources
A compute resource is also referred to simply as a “resource,” and each resource type is a distinctly
measurable quantity at the container level. By default a pod’s compute resources are unbounded, only
limited by the node capacity. A pod’s container could optionally specify resource request and limit levels for
each type of resource, as discussed in the next section. Specifying explicit values for resource request and
limit is recommended for the following reasons:
Doing so makes it easier for the Scheduler to assign pods on a node.
It makes it easier for a Scheduler to handle excess resources and contention of
resources.
Available node capacity could make some pods non-schedulable on the
node if the pod’s containers require more capacity than the node capacity.
Specifying resource requests and limits makes feasible a better design of the pod
scheduling.
Separate namespaces could be created for development and production
workloads with separate resource requests and limits, the resource consumption
being different for different types of workloads.
More efficient utilization of a cluster’s resources is made feasible by specifying
explicit requests and limits for resources. While exceeding a node’s capacity is
one issue, a node could be underutilized if a pod that consumes only a fraction of
the node’s capacity is scheduled on the node, with the remaining node capacity
neither suitable for scheduling another pod nor used by the pod scheduled.
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