Understanding Resource Quotas

In this lesson, we dive into the implementation of resource quotas in Kubernetes, specifically tailored for multi-tenant environments. This refresher builds on concepts covered in the CKA Certification Course - Certified Kubernetes Administrator and focuses on how resource quotas ensure fair resource distribution and prevent resource exhaustion across different teams or services.

Resource quota objects in Kubernetes provide administrators with a mechanism to enforce limits on resources such as CPU, memory, and storage for pods and containers. This control is vital for multi-tenancy as it prevents any single namespace from consuming excessive resources, thereby maintaining balanced and predictable cluster performance.

Example: Resource Quota for a Namespace

The following example demonstrates a Kubernetes resource quota configuration that restricts the resource consumption for a specific namespace named "namespace_a". This setup limits resource requests to 4 CPUs and 16 GiB of memory, while capping resource limits at 8 CPUs and 32 GiB of memory.

apiVersion: v1
kind: ResourceQuota
metadata:
  name: cpu-memory-quota
  namespace: namespace_a
spec:
  hard:
    requests.cpu: "4"
    requests.memory: 16Gi
    limits.cpu: "8"
    limits.memory: 32Gi

Example: Pod with Resource Restrictions

Here’s an example of a pod configuration that adheres to the resource constraints defined for "namespace_a". The pod, using the nginx image, sets specific resource requests and limits to ensure it operates within the allocated boundaries:

apiVersion: v1
kind: Pod
metadata:
  name: resource-limited-pod
  namespace: namespace_a
spec:
  containers:
  - name: resource-limited-container
    image: nginx
    resources:
      requests:
        cpu: "250m"
        memory: "64Mi"
      limits:
        cpu: "500m"
        memory: "128Mi"

This configuration ensures that the pod operates within the specified resource limits, which in turn contributes to a well-balanced resource allocation across multi-tenant environments. By enforcing these limits, Kubernetes helps prevent any single pod from monopolizing cluster resources, supporting a fair and stable operating environment for all users.

For more detailed information on Kubernetes resource management, explore the Kubernetes Documentation.