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Configure Quotas for API Objects

This page shows how to configure quotas for API objects, including PersistentVolumeClaims and Services. A quota restricts the number of objects, of a particular type, that can be created in a namespace. You specify quotas in a ResourceQuota object.

• Before you begin
• Create a namespace
• Create a ResourceQuota
• Create a PersistentVolumeClaim
• Attempt to create a second PersistentVolumeClaim
• Notes
• Clean up
• What’s next
  • For cluster administrators
  • For app developers

Before you begin

You need to have a Kubernetes cluster, and the kubectl command-line tool must be configured to communicate with your cluster. If you do not already have a cluster, you can create one by using Minikube, or you can use one of these Kubernetes playgrounds:

• Katacoda
• Play with Kubernetes

To check the version, enter kubectl version.

Create a namespace

Create a namespace so that the resources you create in this exercise are isolated from the rest of your cluster.

kubectl create namespace quota-object-example

Create a ResourceQuota

Here is the configuration file for a ResourceQuota object:

quota-objects.yaml
apiVersion: v1 kind: ResourceQuota metadata: name: object-quota-demo spec: hard: persistentvolumeclaims: "1" services.loadbalancers: "2" services.nodeports: "0"

Create the ResourceQuota:

kubectl create -f https://k8s.io/docs/tasks/administer-cluster/quota-objects.yaml --namespace=quota-object-example

View detailed information about the ResourceQuota:

kubectl get resourcequota object-quota-demo --namespace=quota-object-example --output=yaml

The output shows that in the quota-object-example namespace, there can be at most one PersistentVolumeClaim, at most two Services of type LoadBalancer, and no Services of type NodePort.

status:
  hard:
    persistentvolumeclaims: "1"
    services.loadbalancers: "2"
    services.nodeports: "0"
  used:
    persistentvolumeclaims: "0"
    services.loadbalancers: "0"
    services.nodeports: "0"

Create a PersistentVolumeClaim

Here is the configuration file for a PersistentVolumeClaim object:

quota-objects-pvc.yaml
kind: PersistentVolumeClaim apiVersion: v1 metadata: name: pvc-quota-demo spec: storageClassName: manual accessModes: - ReadWriteOnce resources: requests: storage: 3Gi

Create the PersistentVolumeClaim:

kubectl create -f https://k8s.io/docs/tasks/administer-cluster/quota-objects-pvc.yaml --namespace=quota-object-example

Verify that the PersistentVolumeClaim was created:

kubectl get persistentvolumeclaims --namespace=quota-object-example

The output shows that the PersistentVolumeClaim exists and has status Pending:

NAME             STATUS
pvc-quota-demo   Pending

Attempt to create a second PersistentVolumeClaim

Here is the configuration file for a second PersistentVolumeClaim:

quota-objects-pvc-2.yaml
kind: PersistentVolumeClaim apiVersion: v1 metadata: name: pvc-quota-demo-2 spec: storageClassName: manual accessModes: - ReadWriteOnce resources: requests: storage: 4Gi

Attempt to create the second PersistentVolumeClaim:

kubectl create -f https://k8s.io/docs/tasks/administer-cluster/quota-objects-pvc-2.yaml --namespace=quota-object-example

The output shows that the second PersistentVolumeClaim was not created, because it would have exceeded the quota for the namespace.

persistentvolumeclaims "pvc-quota-demo-2" is forbidden:
exceeded quota: object-quota-demo, requested: persistentvolumeclaims=1,
used: persistentvolumeclaims=1, limited: persistentvolumeclaims=1

Notes

These are the strings used to identify API resources that can be constrained by quotas:

Clean up

Delete your namespace:

kubectl delete namespace quota-object-example

What’s next

For cluster administrators

• Configure Default Memory Requests and Limits for a Namespace

• Configure Default CPU Requests and Limits for a Namespace

• Configure Minimum and Maximum Memory Constraints for a Namespace

• Configure Minimum and Maximum CPU Constraints for a Namespace

• Configure Memory and CPU Quotas for a Namespace

• Configure a Pod Quota for a Namespace

For app developers

• Assign Memory Resources to Containers and Pods

• Assign CPU Resources to Containers and Pods

• Configure Quality of Service for Pods