Assign Extended Resources to a Container

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:

• Killercoda
• Play with Kubernetes

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