Kubernetes - Resource Requirements

it’s the Kubernetes scheduler that decides which node a pod goes to, the schedular takes on consideration the amount of resources required by a pod and those available on the nodes and identifies the best node to place a pod on.

you can specify the amount of CPU and Memory when you spin up a new pod, to do this in pod-definition.yaml file you can put this under spec you should add a section called resources and specify the required resources you can also specify the limits where your application is not allowed to use more than that limit

...
spec:
	containers:
	- name: web-app
	  resources:
		requests:
			mem: "1Gi"
			cpu: 2
		limits:
			mem: "2Gi"
			cpu: 4
 

you can also create a limitrange resource object

apiVersion: v1
kind: LimitRange
metadata:
  name: cpu-resource-constraint
spec:
  limits:
  - default: # this section defines default limits
      cpu: 500m
    defaultRequest: # this section defines default requests
      cpu: 500m
    max: # max and min define the limit range
      cpu: "1"
    min:
      cpu: 100m
    type: Container

resource quotas

is also another way to create resource limits on namespace level, so a resource quota is a namespace level object

 
apiVersion: v1
kind: ResourceQuota
metadata: 
	name: resource-quota
spec:
	hard:
		requests.cpu: 2
		requests.mem: "1Gi"
		limits.cpu: 4
		limits.mem: "**2Gi**"