What's New in Kubernetes 1.31 Release

Table of Contents

Kubernetes 1.31, codenamed “Elli,” marks another significant stride in container orchestration. This release introduces a suite of enhancements that address critical areas such as networking, security, storage, and resource management. Let’s delve into the key features and their implications.

Networking Enhancements

Improved Ingress Connectivity Reliability

Kubernetes 1.31 significantly bolsters ingress connectivity reliability, especially for load balancers. This is achieved through enhancements in kube-proxy, which now implements a connection draining mechanism for terminating nodes.

Example Service Configuration:

apiVersion: v1
kind: Service
metadata:
  name: my-loadbalancer-service
spec:
  type: LoadBalancer
  externalTrafficPolicy: Cluster
  selector:
    app: my-app
  ports:
    - protocol: TCP
      port: 80
      targetPort: 9376

nftables Backend for Kube-Proxy

Kubernetes 1.31 introduces nftables as a backend option for kube-proxy, offering potential performance improvements and enhanced flexibility.

Enabling nftables:

To enable nftables, set the NFTablesProxyMode feature gate to true.

Multiple Service CIDRs

Addressing the challenge of IP exhaustion in large-scale deployments, Kubernetes 1.31 allows for multiple Service CIDRs.

Example kubeadm Configuration:

apiVersion: kubeadm.k8s.io/v1beta2
kind: ClusterConfiguration
networking:
  serviceSubnet: "10.96.0.0/12,10.100.0.0/16"

Traffic Distribution for Services

Kubernetes 1.31 introduces the trafficDistribution field in the Service specification, offering more granular control over traffic routing.

Example Service Configuration:

apiVersion: v1
kind: Service
metadata:
  name: my-service
spec:
  selector:
    app: my-app
  ports:
    - protocol: TCP
      port: 80
      targetPort: 9376
  trafficDistribution:
    policy: Weighted
    weight: 70

Security Enhancements

AppArmor Support (GA)

Kubernetes 1.31 brings stable AppArmor support, enabling granular security policies for containers and pods.

Example Pod Specification:

apiVersion: v1
kind: Pod
metadata:
  name: my-pod
spec:
  containers:
    - name: my-container
      image: my-image
      securityContext:
        appArmor:
        profileName: my-apparmor-profile

Bound Service Account Token Improvements (Beta)

This feature enhances security by embedding node information in tokens and extending token functionalities.

Finer-Grained Authorization Based on Selectors (Alpha)
Allows webhook authorizers to use label and field selectors for more granular authorization decisions, improving security by restricting access based on specific resource attributes.

Storage Improvements

Persistent Volume Last Phase Transition Time (GA)
Introduces a timestamp field in PersistentVolumes to record the last phase transition time, aiding in troubleshooting and management.
Changes to Reclaim Policy for PersistentVolumes (Beta)

Ensures that the reclaim policy is respected even after the PVC is deleted, preventing potential storage leaks.

Kubernetes VolumeAttributesClass ModifyVolume (Beta)

Allows for dynamic modification of volume parameters, improving flexibility in managing storage resources.

AI/ML and Hardware Management

New DRA APIs for Better Hardware Management (Alpha)
Introduces structured parameters within the dynamic resource allocation (DRA) API, enabling features like cluster autoscaling for hardware resources like GPUs.

Example ResourceClaim:

apiVersion: resource.k8s.io/v1alpha1
kind: ResourceClaim
metadata:
   name: ai-workload
spec:
  resourceClassName: nvidia-gpu
  parameters:
    gpuType: "A100"
    memory: "16Gi"
    compute: "2"

Support for Image Volumes (Alpha)

Enables using OCI images as native volumes in pods, providing flexible storage solutions for AI/ML workloads.
Exposing Device Health Information Through Pod Status (Alpha)
Provides real-time health information about allocated devices within a Pod, facilitating better monitoring and management of hardware resources.

Additional Enhancements

Kubernetes 1.31 also includes improvements in areas like scheduling, CLI, and instrumentation.

For a comprehensive overview, refer to the official release notes.

Resources:

Kubernetes project on GitHub
Get involved with the Kubernetes tools community
Follow @kubetools on Twitter

What’s New in Kubernetes 1.31 Release