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Assign Extended Resources to a Container

This page shows how to assign extended resources to a Container.

• Before you begin
• Assign an extended resource to a Pod
• Attempt to create a second Pod
• Clean up
• What's next

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.

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/foo where 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:

pods/resource/extended-resource-pod.yaml
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.

pods/resource/extended-resource-pod-2.yaml
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

Clean up

Delete the Pods that you created for this exercise:

kubectl delete pod extended-resource-demo
kubectl delete pod extended-resource-demo-2

What's next

For application developers

• Assign Memory Resources to Containers and Pods
• Assign CPU Resources to Containers and Pods

For cluster administrators

• Advertise Extended Resources for a Node

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