The Cloud Native Computing Foundation (CNCF) recently released Kubernetes 1.23. The version adds new features like events subcommand for kubectl, gRPC-Probes and expression language validation for custom resources, generally available or stable features like generic ephemeral volumes, horizontal pod autoscaling and IPv4 / IPv6 dual-stack networks, beta functions like PodSecurity and legacy features like FlexVolume.
The new version kubectl, the command line tool for executing commands for clusters, includes an event subcommand (kubectl events) to better troubleshoot problems. The new subcommand fixes problems with kubectl get events, including sorting and viewing events.
gRPC probes were introduced so that developers can improve application resilience by adding liveness or readiness probes, not only for the HTTP or TCP protocols, but also for gRPC. a high performance framework, widely used for distributed applications and services, that allows a client application to seamlessly invoke a method on a remote server.
In version 1.23 there is a validation mechanism for Custom Resource Definitions (CRDs). This makes it possible to have everything CRD related in one place instead of writing validation webhooks. The validation rules use the Common Expression Language (CEL).
Generic ephemeral volumes moved to GA in version 1.23. Such volumes provide storage for pods for temporary data and are usually empty after provisioning. You can work with any storage driver that supports dynamic provisioning.
Additionally, Version 2 of the HorizontalPodAutoscaler (HPA), a Kubernetes component that automatically updates workloads to meet demand, has been downgraded to GA. The API auto-scaling / v2beta2 is now replaced by Autoscaling / v2.
In addition, IPv4 / IPv6 dual-stack mode network support has been switched to GA. This allows developers to use both IPv4 and IPv6 addresses for pods and to run clusters in production in dual-stack mode.
PodSecurity has been moved to beta in version 1.23 and replaces the outdated PodSecurityPolicy access controller. The new access controller can enforce pod security standards, a set of guidelines ranging from very permissive to very restrictive, for a namespace based on a specific namespace label.
In addition, the 1.23 Container Runtime Interface (CRI) v1 API has been upgraded to beta and become a project-wide standard. CRI is a plug-in interface that enables the Kubelet to use many container runtimes. For example, Docker can be the container runtime for one cluster and containerd for another.
FlexVolume, a plugin interface for dealing with storage drivers, is obsolete in 1.23. FlexVolume driver users are recommended to move their workloads to Container Storage Interface (CSI) drivers.
Kubernetes is open source software that automates the deployment, scaling, and management of application containers.
According to the release notes, Kubernetes version 1.23 has 47 improvements, including 11 generally available or stable, 17 in beta, and 19 in alpha. In addition, a feature is obsolete. Version 1.23 is the last version for 2021.
A CNCF webinar is planned for January 4, 2022, in which the most important functions of the new version will be explained.