--- title: Configure Quality of Service for Pods content_template: templates/task weight: 30 --- {{% capture overview %}} This 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 scheduling and evicting Pods. {{% /capture %}} {{% capture prerequisites %}} {{< include "task-tutorial-prereqs.md" >}} {{< version-check >}} {{% /capture %}} {{% capture steps %}} ## QoS classes When Kubernetes creates a Pod it assigns one of these QoS classes to the Pod: * Guaranteed * Burstable * BestEffort ## Create a namespace Create a namespace so that the resources you create in this exercise are isolated from the rest of your cluster. ```shell kubectl create namespace qos-example ``` ## Create a Pod that gets assigned a QoS class of Guaranteed For a Pod to be given a QoS class of Guaranteed: * Every Container in the Pod must have a memory limit and a memory request, and they must be the same. * Every Container in the Pod must have a CPU limit and a CPU request, and they must be the same. Here is the configuration file 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: {{< codenew file="pods/qos/qos-pod.yaml" >}} Create the Pod: ```shell kubectl apply -f https://k8s.io/examples/pods/qos/qos-pod.yaml --namespace=qos-example ``` View detailed information about the Pod: ```shell 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. ```yaml spec: containers: ... resources: limits: cpu: 700m memory: 200Mi requests: cpu: 700m memory: 200Mi ... 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. {{< /note >}} Delete your Pod: ```shell kubectl delete pod qos-demo --namespace=qos-example ``` ## Create a Pod that gets assigned a QoS class of Burstable A 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. Here is the configuration file for a Pod that has one Container. The Container has a memory limit of 200 MiB and a memory request of 100 MiB. {{< codenew file="pods/qos/qos-pod-2.yaml" >}} Create the Pod: ```shell kubectl apply -f https://k8s.io/examples/pods/qos/qos-pod-2.yaml --namespace=qos-example ``` View detailed information about the Pod: ```shell kubectl get pod qos-demo-2 --namespace=qos-example --output=yaml ``` The output shows that Kubernetes gave the Pod a QoS class of Burstable. ```yaml spec: containers: - image: nginx imagePullPolicy: Always name: qos-demo-2-ctr resources: limits: memory: 200Mi requests: memory: 100Mi ... qosClass: Burstable ``` Delete your Pod: ```shell kubectl delete pod qos-demo-2 --namespace=qos-example ``` ## Create a Pod that gets assigned a QoS class of BestEffort For 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 the configuration file for a Pod that has one Container. The Container has no memory or CPU limits or requests: {{< codenew file="pods/qos/qos-pod-3.yaml" >}} Create the Pod: ```shell kubectl apply -f https://k8s.io/examples/pods/qos/qos-pod-3.yaml --namespace=qos-example ``` View detailed information about the Pod: ```shell kubectl get pod qos-demo-3 --namespace=qos-example --output=yaml ``` The output shows that Kubernetes gave the Pod a QoS class of BestEffort. ```yaml spec: containers: ... resources: {} ... qosClass: BestEffort ``` Delete your Pod: ```shell kubectl delete pod qos-demo-3 --namespace=qos-example ``` ## Create a Pod that has two Containers Here is the configuration file 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. {{< codenew file="pods/qos/qos-pod-4.yaml" >}} 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: ```shell kubectl apply -f https://k8s.io/examples/pods/qos/qos-pod-4.yaml --namespace=qos-example ``` View detailed information about the Pod: ```shell kubectl get pod qos-demo-4 --namespace=qos-example --output=yaml ``` The output shows that Kubernetes gave the Pod a QoS class of Burstable: ```yaml spec: containers: ... name: qos-demo-4-ctr-1 resources: requests: memory: 200Mi ... name: qos-demo-4-ctr-2 resources: {} ... qosClass: Burstable ``` Delete your Pod: ```shell kubectl delete pod qos-demo-4 --namespace=qos-example ``` ## Clean up Delete your namespace: ```shell kubectl delete namespace qos-example ``` {{% /capture %}} {{% capture whatsnext %}} ### For app developers * [Assign Memory Resources to Containers and Pods](/docs/tasks/configure-pod-container/assign-memory-resource/) * [Assign CPU Resources to Containers and Pods](/docs/tasks/configure-pod-container/assign-cpu-resource/) ### For cluster administrators * [Configure Default Memory Requests and Limits for a Namespace](/docs/tasks/administer-cluster/memory-default-namespace/) * [Configure Default CPU Requests and Limits for a Namespace](/docs/tasks/administer-cluster/cpu-default-namespace/) * [Configure Minimum and Maximum Memory Constraints for a Namespace](/docs/tasks/administer-cluster/memory-constraint-namespace/) * [Configure Minimum and Maximum CPU Constraints for a Namespace](/docs/tasks/administer-cluster/cpu-constraint-namespace/) * [Configure Memory and CPU Quotas for a Namespace](/docs/tasks/administer-cluster/quota-memory-cpu-namespace/) * [Configure a Pod Quota for a Namespace](/docs/tasks/administer-cluster/quota-pod-namespace/) * [Configure Quotas for API Objects](/docs/tasks/administer-cluster/quota-api-object/) * [Control Topology Management policies on a node](/docs/tasks/administer-cluster/topology-manager/) {{% /capture %}}