LWKD: Week Ending September 3, 2023
Last Week In Kubernetes Development
Week Ending September 3, 2023
Developer News
The Kubernetes legacy Linux package repositories, apt.kubernetes.io and yum.kubernetes.io, have been deprecated and will be frozen on September 13, 2023. Use the new Kubernetes community-owned package repository at pkgs.k8s.io.
Kubernetes Contributor Summit Shanghai will take place on Sept. 26. Registration is open, as is the CfP for team meetings and discussions.
Reminders:
- Vote for Kubernetes Steering Committee
- Registration and CfP for Contributor Summit Chicago is also still open.
Release Schedule
Next Deadline: Production Readiness Review Freeze, September 28th
We are now officially in the 1.29 cycle, and Release Lead Priyanka Saggu has a “sneak peek” for you. That also means that Enhancements deadlines are coming soon (PRR: 28 September, Enhancements: 6 October).
The entire tentative schedule for the 1.29 release can now be found at GitHub - Kubernetes SIG Release. Weekly meetings for the 1.29 release will start from Wednesday, September 6, 2023. You can find details, meeting links, and agendas here.
Cherry Pick deadline for the next set of patch releases is this Friday.
Featured PRs
#119157: WebSocket Client and V5 RemoteCommand Subprotocol
Since their addition in the pre-history of Kubernetes, the streaming APIs have used the SPDY ("speedy" to its friends) protocol. While SPDY was intended more for general web usage, the broader internet quickly centered around HTTP/2 as a better successor protocol. But our APIs for things like kubectl exec required bidirectional communication features that HTTP/2 didn't inherit from its predecessor. So despite being effectively unsupported by web browsers and general purpose web servers, we've continued to use this SPDY plumbing for many years. This is mostly fine, but it does create some difficulties as things like proxy servers and firewalls don't natively understand SPDY traffic anymore.
Fortunately there is a replacement protocol in common usage across the internet, WebSockets. While mostly used for bidirectional data communications with browser-based JavaScript, the WebSockets protocol is flexible enough to take over all our SPDY-based APIs. This effort has been ongoing for a while, as it became clear that SPDY was a dead-end technology, and this PR is another big leap forward towards the future. It adds an official client which can later be used from things like kubectl, as well as another iteration of a WS-based API for kubectl exec.
#117503: [KEP-2395] Phase 4 - Disabling In-Tree Providers
A big push over the past few releases has been the expunge the last bits of in-tree providers for things like cloud servers and storage. While these drivers were really convenient in the early days of Kubernetes, when we were a small community and most vendors didn't even know what containers were, let alone have dedicated support tooling for us. As we've grown both as a piece of software and as a community, they started to hold us back. Vendors wanted to get "quick fixes" in patch releases, or to support advanced or in-development features that the core team couldn't test against. So we decided to push vendor-specific and situational drivers into their own projects, some still owned by us but many managed by the underlying vendors.
This PR is very close to the end of the migration for cloud controllers, all in-tree cloud providers are now disabled by default and require a feature flag to turn them back on. The final nail in the coffin will making this flag mandatory, which isn't happening yet, but hopefully soon. If you've been putting off your CCM migration, be sure to prepare for it before upgrading to 1.29!
KEP of the Week
KEP-4009: Add CDI devices to device plugin API
This KEP proposes extending the Device Plugin API in Kubernetes to include a field for specifying Container Device Interface (CDI) device IDs in the AllocateResponse. This addition allows device plugin implementations to uniquely specify devices using their fully-qualified CDI device names, simplifying the process of injecting devices into containers.
The motivation behind this change is to align Kubernetes with the CDI standard, which provides a standardized way for device vendors to describe resource requirements and access to specific devices. The CDI device IDs are included in the response from the device plugin and forwarded to the CRI runtimes for container execution.
This KEP outlines the design details, test plan, graduation criteria, and production readiness review for this enhancement, with a focus on ensuring compatibility and minimal impact on existing components. The goal is to enable device plugin authors to leverage CDI for device injection without necessitating a shift to Dynamic Resource Allocation (DRA) based implementations.
This KEP was created by Evan Lezar and received the alpha milestone in v1.28.
Other Merges
- Scheduler: fix concurrent event tracking
- ExternalIPs support ExternalTrafficPolicy
- APIserver adds
--authentication-configflag - A fix to the data race in etcd metrics
kubectl eventsto filter events by group and version for resource with full name- Stability static analyzer to sort the list of metrics in the shell command and not just in the Go program
- More hypens in Resource Claim names
- Kube-proxy should ignore invalid DROP conntrack rules
- Add SidecarContainers feature gate to prevent unexpected regressions with pod restart
- Kubeadm: EtcdLearnerMode is beta, print default configs
- OpenAPI gets cleaned up properly when aggregated APIs are shut down
- Fall back to legacy discovery whenever aggregated discovery fails
- Clean up Jobs (and prevent deadlock) once resource limit is reached
- Add more callback points during drain for triggering custom controllers
Promotions
Deprecated
- Scheduler's selectorSpread plugin is removed, use podTopologySpread instead
- Remove SchedulerPolicyConfigMapKey since nobody uses it
- Remove deprecated v1beta1 API for APF
- Remove 1.22-era legacy ephemeral container support
- Remove Swagger 2.0 support from Kubectl, deprecated since 1.9
Version Updates
Subprojects and Dependency Updates
- kubernetes-sigs/gateway-api had its v0.8.0 release last week. The major new changes include adding service mesh support as per the GAMMA initiative as an experimental feature and moving to CEL validation.
- kubernetes-sigs/cluster-api improved ExtensionConfig reconcile performance.