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Assign Extended Resources to a Container
Kubernetes v1.21 [stable]
This page shows how to assign extended resources to a Container.
Before you begin
You 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:
Before you do this exercise, do the exercise in Advertise Extended Resources for a Node. That will configure one of your Nodes to advertise a dongle resource.
Assign an extended resource to a Pod
To request an extended resource, include the
resources:requests field in your
Container manifest. Extended resources are fully qualified with any domain outside of
*.kubernetes.io/. Valid extended resource names have the form
example.com is replaced with your organization's domain and
foo is a
descriptive resource name.
Here is the configuration file for a Pod that has one Container:
apiVersion: v1 kind: Pod metadata: name: extended-resource-demo spec: containers: - name: extended-resource-demo-ctr image: nginx resources: requests: example.com/dongle: 3 limits: example.com/dongle: 3
In the configuration file, you can see that the Container requests 3 dongles.
Create a Pod:
kubectl apply -f https://k8s.io/examples/pods/resource/extended-resource-pod.yaml
Verify that the Pod is running:
kubectl get pod extended-resource-demo
Describe the Pod:
kubectl describe pod extended-resource-demo
The output shows dongle requests:
Limits: example.com/dongle: 3 Requests: example.com/dongle: 3
Attempt to create a second Pod
Here is the configuration file for a Pod that has one Container. The Container requests two dongles.
apiVersion: v1 kind: Pod metadata: name: extended-resource-demo-2 spec: containers: - name: extended-resource-demo-2-ctr image: nginx resources: requests: example.com/dongle: 2 limits: example.com/dongle: 2
Kubernetes will not be able to satisfy the request for two dongles, because the first Pod used three of the four available dongles.
Attempt to create a Pod:
kubectl apply -f https://k8s.io/examples/pods/resource/extended-resource-pod-2.yaml
Describe the Pod
kubectl describe pod extended-resource-demo-2
The output shows that the Pod cannot be scheduled, because there is no Node that has 2 dongles available:
Conditions: Type Status PodScheduled False ... Events: ... ... Warning FailedScheduling pod (extended-resource-demo-2) failed to fit in any node fit failure summary on nodes : Insufficient example.com/dongle (1)
View the Pod status:
kubectl get pod extended-resource-demo-2
The output shows that the Pod was created, but not scheduled to run on a Node. It has a status of Pending:
NAME READY STATUS RESTARTS AGE extended-resource-demo-2 0/1 Pending 0 6m
Delete the Pods that you created for this exercise:
kubectl delete pod extended-resource-demo kubectl delete pod extended-resource-demo-2