# Configure Quality of Service for Pods

Configure Quality of Service for PodsThis page shows how to configure Pods so that they will be assigned particular Quality of Service (QoS) classes. Kubernetes uses QoS classes to make decisions about evicting Pods when Node resources are exceeded.When Kubernetes creates a Pod it assigns one of these QoS classes to the Pod:GuaranteedBurstableBestEffortBefore you beginYou need to have a Kubernetes cluster, and the kubectl command-line tool must be configured to communicate with your cluster. It is recommended to run this tutorial on a cluster with at least two nodes that are not acting as control plane hosts. If you do not already have a cluster, you can create one by using minikube or you can use one of these Kubernetes playgrounds:iximiuz LabsKillercodaKodeKloudPlay with KubernetesYou also need to be able to create and delete namespaces.Create a namespaceCreate a namespace so that the resources you create in this exercise are isolated from the rest of your cluster.kubectl create namespace qos-example Create a Pod that gets assigned a QoS class of GuaranteedFor a Pod to be given a QoS class of Guaranteed:Every Container in the Pod must have a memory limit and a memory request.For every Container in the Pod, the memory limit must equal the memory request.Every Container in the Pod must have a CPU limit and a CPU request.For every Container in the Pod, the CPU limit must equal the CPU request.These restrictions apply to init containers and app containers equally. Ephemeral containers cannot define resources so these restrictions do not apply.Here is a manifest for a Pod that has one Container. The Container has a memory limit and a memory request, both equal to 200 MiB. The Container has a CPU limit and a CPU request, both equal to 700 milliCPU:pods/qos/qos-pod.yaml apiVersion: v1 kind: Pod metadata: name: qos-demo namespace: qos-example spec: containers: - name: qos-demo-ctr image: nginx resources: limits: memory: "200Mi" cpu: "700m" requests: memory: "200Mi" cpu: "700m" Create the Pod:kubectl apply -f https://k8s.io/examples/pods/qos/qos-pod.yaml --namespace=qos-example View detailed information about the Pod:kubectl get pod qos-demo --namespace=qos-example --output=yaml The output shows that Kubernetes gave the Pod a QoS class of Guaranteed. The output also verifies that the Pod Container has a memory request that matches its memory limit, and it has a CPU request that matches its CPU limit.spec: containers: ... resources: limits: cpu: 700m memory: 200Mi requests: cpu: 700m memory: 200Mi ... status: qosClass: Guaranteed Note:If a Container specifies its own memory limit, but does not specify a memory request, Kubernetes automatically assigns a memory request that matches the limit. Similarly, if a Container specifies its own CPU limit, but does not specify a CPU request, Kubernetes automatically assigns a CPU request that matches the limit.Clean upDelete your Pod:kubectl delete pod qos-demo --namespace=qos-example Create a Pod that gets assigned a QoS class of BurstableA Pod is given a QoS class of Burstable if:The Pod does not meet the criteria for QoS class Guaranteed.At least one Container in the Pod has a memory or CPU request or limit.Here is a manifest for a Pod that has one Container. The Container has a memory limit of 200 MiB and a memory request of 100 MiB.pods/qos/qos-pod-2.yaml apiVersion: v1 kind: Pod metadata: name: qos-demo-2 namespace: qos-example spec: containers: - name: qos-demo-2-ctr image: nginx resources: limits: memory: "200Mi" requests: memory: "100Mi" Create the Pod:kubectl apply -f https://k8s.io/examples/pods/qos/qos-pod-2.yaml --namespace=qos-example View detailed information about the Pod:kubectl get pod qos-demo-2 --namespace=qos-example --output=yaml The output shows that Kubernetes gave the Pod a QoS class of Burstable:spec: containers: - image: nginx imagePullPolicy: Always name: qos-demo-2-ctr resources: limits: memory: 200Mi requests: memory: 100Mi ... status: qosClass: Burstable Clean upDelete your Pod:kubectl delete pod qos-demo-2 --namespace=qos-example Create a Pod that gets assigned a QoS class of BestEffortFor a Pod to be given a QoS class of BestEffort, the Containers in the Pod must not have any memory or CPU limits or requests.Here is a manifest for a Pod that has one Container. The Container has no memory or CPU limits or requests:pods/qos/qos-pod-3.yaml apiVersion: v1 kind: Pod metadata: name: qos-demo-3 namespace: qos-example spec: containers: - name: qos-demo-3-ctr image: nginx Create the Pod:kubectl apply -f https://k8s.io/examples/pods/qos/qos-pod-3.yaml --namespace=qos-example View detailed information about the Pod:kubectl get pod qos-demo-3 --namespace=qos-example --output=yaml The output shows that Kubernetes gave the Pod a QoS class of BestEffort:spec: containers: ... resources: {} ... status: qosClass: BestEffort Clean upDelete your Pod:kubectl delete pod qos-demo-3 --namespace=qos-example Create a Pod that has two ContainersHere is a manifest for a Pod that has two Containers. One container specifies a memory request of 200 MiB. The other Container does not specify any requests or limits.pods/qos/qos-pod-4.yaml apiVersion: v1 kind: Pod metadata: name: qos-demo-4 namespace: qos-example spec: containers: - name: qos-demo-4-ctr-1 image: nginx resources: requests: memory: "200Mi" - name: qos-demo-4-ctr-2 image: redis Notice that this Pod meets the criteria for QoS class Burstable. That is, it does not meet the criteria for QoS class Guaranteed, and one of its Containers has a memory request.Create the Pod:kubectl apply -f https://k8s.io/examples/pods/qos/qos-pod-4.yaml --namespace=qos-example View detailed information about the Pod:kubectl get pod qos-demo-4 --namespace=qos-example --output=yaml The output shows that Kubernetes gave the Pod a QoS class of Burstable:spec: containers: ... name: qos-demo-4-ctr-1 resources: requests: memory: 200Mi ... name: qos-demo-4-ctr-2 resources: {} ... status: qosClass: Burstable Retrieve the QoS class for a PodRather than see all the fields, you can view just the field you need:kubectl --namespace=qos-example get pod qos-demo-4 -o jsonpath='{ .status.qosClass}{"\n"}' Burstable Clean upDelete your namespace:kubectl delete namespace qos-example What's nextFor app developersAssign Memory Resources to Containers and PodsAssign CPU Resources to Containers and PodsFor cluster administratorsConfigure Default Memory Requests and Limits for a NamespaceConfigure Default CPU Requests and Limits for a NamespaceConfigure Minimum and Maximum Memory Constraints for a NamespaceConfigure Minimum and Maximum CPU Constraints for a NamespaceConfigure Memory and CPU Quotas for a NamespaceConfigure a Pod Quota for a NamespaceConfigure Quotas for API ObjectsControl Topology Management policies on a node