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

Chapter 10 ■ Configuring Compute Resources
Overview
The two types of resources, compute resources and API resources, are shown in Figure 10-2. Compute
resources are measurable quantities that can be requested by containers in a pod, allocated to containers
and consumed by containers. API resources are Kubernetes objects such as pods and services, which are
written to and retrieved from the API server.
Kubernetes
Resource
Compute Resources
API Resources
Figure 10-2. Kubernetes resource types
We will only be discussing compute resources in this chapter. By default, compute resources available
to a container or a pod are limited only by the node capacity. While resources are consumed by containers
in a pod (a pod can have one or more container), resources are also implied to be consumed by pods. The
resources requested, allocated, and consumed by a pod are the total of the resources requested, allocated,
and consumed by the containers in the pod. Node capacity comprises the resources available to a node in
terms of CPUs, memory, and the maximum number of pods that can be scheduled on the node. The total of
all allocated resources for each resource (CPUs, memory) to containers running on a node cannot exceed
the node capacity for the resource. Kubernetes Scheduler ensures that sufficient resources are available on
a node before it schedules a pod on the node. Even after scheduling a node, the Scheduler ensures that the
total of allocated resources on a node does not exceed the node capacity, which it cannot by virtue of the
node capacity. The Scheduler only monitors the containers started by the kubelet and not containers started
by the Docker engine. This chapter looks at the following topics:
Types of compute resources
Resource requests and limits
Quality of service
Setting the environment
Finding node capacity
Creating a pod with resources specified
Overcommitting resource limits
Reserving node resources
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