Kubernetes Version History: Complete Overview

Kubernetes Version History

Kubernetes follows a regular release cadence with new minor versions every three to four months. Understanding version history helps you plan upgrades and understand feature evolution.

Kubernetes Release Cadence

Kubernetes maintains a predictable release schedule:

  • Minor releases: Every 3-4 months
  • Patch releases: As needed for bug fixes and security patches
  • Support policy: Latest 3 minor versions are supported

Major Version Eras

Kubernetes 1.0-1.5 (2015-2016): The Foundation

Focus: Core functionality and stability

Key Features Introduced:

  • Basic pod, service, and replication controller APIs
  • Service discovery and load balancing
  • Health checks and restart policies
  • Basic scheduling

Kubernetes 1.6-1.10 (2016-2018): Rapid Expansion

Focus: Advanced features and enterprise readiness

Key Features Introduced:

  • Deployments and StatefulSets
  • RBAC (Role-Based Access Control)
  • Network Policies
  • Custom Resource Definitions (CRDs)
  • Helm package manager adoption

Kubernetes 1.11-1.17 (2018-2019): Maturation

Focus: Performance, stability, and extensibility

Key Features Introduced:

  • CSI (Container Storage Interface)
  • Windows container support
  • Pod Priority and Preemption
  • Topology Manager
  • Server-side Apply

Kubernetes 1.18-1.23 (2020-2021): Modern Platform

Focus: Security, observability, and developer experience

Key Features Introduced:

  • Pod Security Standards
  • Generic Ephemeral Volumes
  • IPv6 dual-stack
  • Better Windows support
  • Enhanced API capabilities

Kubernetes 1.24-1.30 (2022-2024): Cloud-Native Standard

Focus: Security hardening, performance, and ecosystem

Key Features Introduced:

  • Removal of Dockershim
  • Gateway API evolution
  • Enhanced security policies
  • Performance optimizations
  • Better multi-cluster support

Recent Major Releases

Kubernetes 1.28 (August 2023)

Theme: Planternetes (Planning for the Future)

Key Features:

  • Sidecar containers (alpha)
  • Native sidecar container support
  • Improved job management
  • Enhanced node resource management

Deprecations:

  • Various beta APIs removed

Kubernetes 1.29 (December 2023)

Theme: Mandala

Key Features:

  • LoadBalancer IP mode (beta)
  • Structured authorization configuration
  • Better resource slice management
  • Enhanced validation rules

Kubernetes 1.30 (April 2024)

Theme: Uwubernetes

Key Features:

  • Improved service mesh integration
  • Enhanced networking capabilities
  • Better observability features
  • Performance improvements

Version Support Lifecycle

Support Policy

  • Latest 3 minor versions receive active support
  • Security patches for supported versions
  • Bug fixes typically for latest 2 versions
  • Deprecated features removed after 2 releases

Upgrade Planning

Recommendation: Stay within 2 minor versions for easier upgrades

  • Plan upgrades quarterly
  • Test in non-production first
  • Review deprecation notices
  • Update tools and dependencies

Deprecation Process

Timeline

  1. Deprecation Announcement: Feature marked as deprecated (2 releases notice)
  2. Warning Phase: Feature still works but logs warnings
  3. Removal: Feature removed in next major release

Common Deprecations

  • API Versions: Beta APIs promoted to stable and old ones removed
  • Container Runtimes: Dockershim removal in 1.24
  • Security Features: Pod Security Policies replaced by Pod Security Standards

Version Comparison: Key Differences

v1.23 vs v1.24

Major Change: Dockershim removal

  • Docker runtime no longer supported
  • Must use containerd, CRI-O, or other CRI-compatible runtime

v1.24 vs v1.25

Focus: API stability and security

  • Beta APIs promoted
  • Enhanced security features
  • Better resource management

v1.25 vs v1.26

Focus: Performance and observability

  • Performance improvements
  • Better metrics and monitoring
  • Enhanced debugging capabilities

Choosing a Kubernetes Version

For New Clusters

Recommended: Use latest stable version

  • Latest features and security patches
  • Best performance
  • Active community support

For Existing Clusters

Recommended: Stay within 2 minor versions

  • Easier upgrade path
  • Reduced risk of breaking changes
  • Better compatibility with tools

Version Selection Factors

  1. Feature Requirements: Do you need specific features?
  2. Tool Compatibility: Do your tools support the version?
  3. Security: Is your version receiving security patches?
  4. Support: Is your version still supported?

Upgrade Strategies

In-Place Upgrades

  • Upgrade control plane first
  • Then upgrade worker nodes
  • Use managed services for easier upgrades

Cluster Replacement

  • Create new cluster with new version
  • Migrate workloads
  • Good for major version jumps

Blue-Green Deployment

  • Run two clusters side-by-side
  • Migrate workloads gradually
  • Minimizes risk

Version-Specific Articles

For detailed information on specific versions:

Checking Your Kubernetes Version

# Check cluster version
kubectl version --short

# Check server version
kubectl version -o json | jq .serverVersion

# Check client version
kubectl version --client --short

Related Resources

Conclusion

Understanding Kubernetes version history helps you:

  • Plan upgrades effectively
  • Understand feature evolution
  • Make informed version choices
  • Stay current with best practices

Kubernetes continues to evolve rapidly while maintaining backward compatibility. Regular upgrades keep you secure and give you access to the latest features and improvements.