Knative 1.8: Serverless on Kubernetes Evolution

Introduction

Knative 1.8, released on November 10, 2022, continues to evolve serverless capabilities on Kubernetes. This release improves serving APIs, enhances eventing capabilities, and delivers better autoscaling for production serverless workloads.

This release is most relevant in day‑2 operations—when you’re upgrading, scaling, or troubleshooting in real clusters. The goal is the same: fewer surprises and more predictable behavior under load.

Serving Improvements

• Service APIs improvements provide better stability and performance for serverless services.
• Revision management gains enhanced lifecycle controls, enabling precise traffic splitting.
• Domain mapping supports custom domains and TLS termination for multi-tenant deployments.
• Container concurrency and scale bounds expose fine-grained controls for resource utilization.

Eventing Enhancements

1. Broker improvements standardize event delivery with configurable retries and dead-letter queues.
2. Trigger filtering enables attribute-based event routing for complex event-driven architectures.
3. Source ecosystem matures with production-ready connectors for Kafka, RabbitMQ, and cloud event sources.
4. Channel implementations provide reliable event delivery with pluggable backends.

Autoscaling Excellence

• KPA (Knative Pod Autoscaler) delivers sub-second scale-to-zero and rapid scale-up.
• Activator optimizations reduce queueing latency and improve request routing during scale transitions.
• Concurrency-based scaling automatically adjusts replica counts based on request load.
• Burst capacity settings prevent traffic spikes from overwhelming newly scaled pods.

Operational Maturity

• Health checks and readiness probes ensure traffic only routes to healthy revisions.
• Metrics integration with Prometheus provides visibility into request rates and autoscaling decisions.
• Distributed tracing support via OpenTelemetry enables end-to-end request observability.
• Multi-cluster support through service mesh integration enables global serverless deployments.

Getting Started

kubectl apply -f https://github.com/knative/serving/releases/download/v1.8.0/serving-crds.yaml
kubectl apply -f https://github.com/knative/serving/releases/download/v1.8.0/serving-core.yaml
kubectl apply -f https://github.com/knative/net-istio/releases/download/v1.8.0/release.yaml

Deploy a serverless service:

kn service create hello \
  --image gcr.io/knative-samples/helloworld-go:latest \
  --env TARGET="Knative 1.8"

Summary

Knative 1.8 continues to evolve as a leading serverless platform, providing teams with a mature, scalable platform for building event-driven applications.