This page shows how to set a quota for the total number of Pods that can run in a namespace. You specify quotas in a ResourceQuota object.
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:
Create a namespace so that the resources you create in this exercise are isolated from the rest of your cluster.
kubectl create namespace quota-pod-example
Here is the configuration file for a ResourceQuota object:
Create the ResourceQuota:
kubectl create -f https://k8s.io/docs/tasks/administer-cluster/quota-pod.yaml --namespace=quota-pod-example
View detailed information about the ResourceQuota:
kubectl get resourcequota pod-demo --namespace=quota-pod-example --output=yaml
The output shows that the namespace has a quota of two Pods, and that currently there are no Pods; that is, none of the quota is used.
spec: hard: pods: "2" status: hard: pods: "2" used: pods: "0"
Here is the configuration file for a Deployment:
In the configuration file,
replicas: 3 tells Kubernetes to attempt to create three Pods, all running the same application.
Create the Deployment:
kubectl create -f https://k8s.io/docs/tasks/administer-cluster/quota-pod-deployment.yaml --namespace=quota-pod-example
View detailed information about the Deployment:
kubectl get deployment pod-quota-demo --namespace=quota-pod-example --output=yaml
The output shows that even though the Deployment specifies three replicas, only two Pods were created because of the quota.
spec: ... replicas: 3 ... status: availableReplicas: 2 ... lastUpdateTime: 2017-07-07T20:57:05Z message: 'unable to create pods: pods "pod-quota-demo-1650323038-" is forbidden: exceeded quota: pod-demo, requested: pods=1, used: pods=2, limited: pods=2'
Delete your namespace:
kubectl delete namespace quota-pod-example