Platform Briefing — Kubernetes 1.21 Release
Kubernetes 1.21 introduced CronJobs and Immutable Secrets as generally available features, marked PodSecurityPolicy for removal, and advanced IPv6 dual-stack networking, shaping upgrade priorities for platform teams.
Executive briefing: The Kubernetes community released version 1.21 on , focusing on workload stability, security hardening, and extensibility for managed clusters.
Key updates
- CronJobs graduate to GA. Production scheduler support now covers cron workloads with improved controller performance.
- Immutable Secrets and ConfigMaps. Operators can enable immutability to prevent accidental overwrites of runtime configuration.
- PodSecurityPolicy deprecation. PSP entered deprecation ahead of removal in 1.25, nudging adopters to switch to Policy-as-Code alternatives.
- IPv6/IPv4 dual-stack beta. Multi-family networking unlocks gradual IPv6 adoption alongside existing IPv4 services.
Implementation guidance
- Audit clusters for PodSecurityPolicy usage and transition to Gatekeeper, Kyverno, or upcoming Pod Security Admission replacements.
- Enable immutable configuration maps for critical workloads to reduce configuration drift.
- Update scheduling and observability playbooks to account for CronJob controller changes.
- Pilot dual-stack networking in staging clusters, validating service discovery and firewall rules.