The Burstable pod has a priority that is higher than BestEffort but lower than Guaranteed. In order to configure a pod to be a Burstable Pod, you need to set resources.request. resources.limit is optional, but the value of resources.request and resources.limit must not be equal:

1. Prepare a pod configuration that has resources.request only:

$ cat burstable.yml
apiVersion: v1
kind: Pod
metadata:
  name: burstable-pod
spec:
  containers:
  - name: nginx
    image: nginx
    resources:
      requests:
        cpu: 0.1
        memory: 10Mi
      limits:
        cpu: 0.5
        memory: 300Mi

2. Create the pod:

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

3. Check the QoS class; it is Burstable:

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