Container Resource Requirements

Kubernetes allows you to specify the CPU and memory requirements for a container. As part of the Pod  spec you can specify CPU and memory requests and limits.

  •  requests
    • the CPU and memory resources required to run a container
    • used by Kubernetes to decide what worker Node a Pod should be deployed to. This ensures there are sufficient resources on the Node to run the Pod.
  •  limits
    • an upper limit for the resource usage of a container
    • if a container exceeds these limits it will likely be destroyed.
    • stops individual containers monopolising resources on a Node.

requests and limits are defined beneath resources in the Pod spec.

apiVersion: v1
kind: Pod
  name: container-resources-pod-demo
    - name: container-resources-pod-demo
      image: busybox
      command: [ "sh", "-c", "echo hello pod security & sleep 3600" ]
          memory: "32Mi"
          cpu: "400m"
          memory: "64Mi"
          cpu: "600m"

Requested memory is 32Mi (32 Mebibytes) which is approximately 32 megabytes. Allowed memory is capped at 64Mi.

CPU is measured in cores. The requested CPU is 400m which represents 400 milliCPUs or 0.4 CPU cores. The upper CPU limit is capped at 600m or 600 milliCPUs.

After running the above Pod you can use kubectl describe to see the resource requirements in the running container.

The sample code for these notes is available here.