The Guaranteed class has the highest priority of resource QoS classes. In the case of a resource shortage, the Kubernetes scheduler will try to retain the Guaranteed pod to the last.

In order to configure a pod to have the guaranteed class, explicitly set the resource limit and resource request as the same value, or only set the resource limit:

1. Prepare a pod configuration that has the same value for resources.limit and resources.request:

$ cat guaranteed.yml
apiVersion: v1
kind: Pod
metadata:
  name: guaranteed-pod
spec:
  containers:
  - name: nginx
    image: nginx
    resources:
      limits:
        cpu: 0.3
        memory: 350Mi
      requests:
        cpu: 0.3
        memory: 350Mi

2. Create the pod on the chap8-no-qos namespace:

$ kubectl create -f guaranteed.yml --namespace=chap8-no-qos
pod "guaranteed-pod" created

3. Check the QoS class; it has the Guaranteed class:

$ kubectl describe pods guaranteed-pod --namespace=chap8-no-qos |grep QoS
QoS Class:       Guaranteed