Kubernetes 1.16 includes several new features such as IPV4/IPV6 dual stack support, PVC cloning, custom resource definition enhancements, and server-side apply moving to the API server. Rancher 2.3 provides the ability to reuse Kubernetes configurations across clusters and is the first to deliver general availability support for Windows containers and Kubernetes with Windows worker nodes. The document discusses these new features in Kubernetes 1.16 and enhancements in Rancher 2.3.

1. Kubernetes 1.16 and
Rancher 2.3
Enhancements
@saiyampathak

2. About myself
Saiyam Pathak
• Twitter - @saiyampathak
• Blog –
https://medium.com/@saiyampathak
• Rancher and Influx Bangalore
Meetup Organizer
• Influx ACE
• Rancher RanchHands member
• Kubernetes Member and APAC
coordinator

3. Kubernetes 1.16
31
Enhancements
8 Stable
8 Beta
15 Alpha

4. IPV4/IPV6 Dual Stack Support
https://github.com/kubernetes/enhancements/issues/563
Alpha in 1.16
IPV6 was added in k8s 1.9: either ipv4 or ipv6 or single-pod-IP-aware
1.16 :
Multiple ipv4/ipv6 address assignment per pod
Native ipv4-to-ipv4 in parallel with ipv6-to-ipv6 communication to, from, and within the cluster
Tested in Bridge CNI plugin, PTP CNI plugin

5. PVC cloning
• Beta 1.16
• Support added for adding existing PVC in the data source field to
indicate that user wants to clone a Volume
• Cloning support (VolumePVCDataSource) is only available for CSI
drivers.
• PVC needs to be in same namespace

6. Custom
Resource
Definition #95
• Graduated
• CRD are the way to extend k8s API to include
custom resource types that behave like native
resource type. Beta since 1.7

7. Publish CRD
open API
schema #692
• Graduated to stable
• CustomResourceDefinition (CRD) allows the
CRD author to define an OpenAPI v3 schema to
enable server-side validation for
CustomResources (CR).

8. Subresources
for custom
resources -
#571
• Graduated to Stable
• /status and /scale subresources for CR’s
• // +kubebuilder:subresource:status

9. Defaulting and Pruning for custom resources- #575
• Pruning- Stable , Defaulting- Beta
• features aiming to facilitate the JSON
handling and processing associated with
CRD
• If pruning is enabled, unspecified fields
in CR on creation and on update are
dropped (preserveUnknownFields)
• Defaulting allows to specify default
values in the OpenAPi validation
schema (CustomResourceDefaulting)

10. Defaulting Sample

11. Webhook
conversion for
custom
resources -
#598
Graduated to stable
Different CRD versions can have different
schemas. You can now handle on-the-fly
conversion between versions defining
and implementing a conversion webhook.

12. Admission
Webhooks -
#492
• Graduated to stable
• Way to extend Kubernetes by putting
hook on object
creation/modification/deletion.
Admission webhooks can mutate or
validate the object
• Extended to single object

13. Add watch
bookmarks
support- #956
Graduted to Beta
Reduce load on ApiServer by minimizing
watch events that needs to be processed
after restarting the watch.
Bookmark represents all objects up to a
given resourceVersion requested by the
client have already been sent.

14. Server-Side Apply - #555
• Graduated to Beta
• `kubectl apply` - moves to control plane/apiserver
• Current problems:
• User does POST > changes something > again apply : boom!!
• User does apply > edit > apply : boom !!
• User does get > edit locally > apply : boom !!
• User tweaks annotations > apply : boom !!

15. Deprecate
and remove
SelfLink -
#1164 NET NEW ALPHA WILL BE DEPRECATED
IN 1 YEAR

16. Building
Kubernetes
without In-
Tree Cloud -
#1179
• Net New Alpha
• Removing in tree cloud provider
implementations code

17. Kubeadm for windows- 995
Advanced configurations with kubeadm(using kustomize) - #1177
• Net New Alpha
• Join windows machine to Kubernetes cluster
• Widows support is there since 1.14
• Rancher 2.3 has windows support (https://rancher.com/blog/2019/2019-10-17-
zero-to-windows-containers-with-rancher-2-3-and-terraform/)
• kubeadm init --experimental-kustomize kubeadm-patches/
• Static pod customizations

18. Kubernetes
metrics
overhaul -
#1206
• Net New Alpha
• Metrics not following instrumentation
guidelines, Prometheus guidelines
• Kubernetes 1.16 removes the
labels pod_name and container_name from
cAdvisor metrics, duplicates
of pod and container.
• Kubernetes 1.17 will deprecate some metrics
like
• apiserver_request_count
• apiserver_request_latencies
• apiserver_request_latencies_summary
• apiserver_dropped_requests

19. Endpoint
Slicing - #752
Net New Alpha
Endpoints object may grow too big and become
problematic; as big objects cannot be stored in etcd
will split endpoints into several Endpoint Slice
resources, solving many of the current API
problems
Any change in an endpoint, Endpoints object is re-
computed, stored and shared with all watchers and
causes problems like rolling upgrades.

20. Ephemeral containers- #277
• Great way to debug pods, as you can’t add regular
container
• Troubleshooting and debugging purpose
• EphemeralContainers – feature gate needs to be enabled
• Fields
like ports, livenessProbe, readinessProbe or lifecycle that
imply a role in a pod will be disallowed.
• Maybe : kubectl debug -c debug-shell --image=debian
target-pod -- bash

21. Node topology
manager - #693
• Alpha
• For Ultra low latency – Machine learning
workloads
• pods running in Guaranteed QoS class that
have an integer cpu value are considered by
the Topology Manager
• Kubelet component centralizes
the coordination of hardware resource
assignments

22. Other
Changes
• #688 Pod overhead: account resources tied to the
pod sandbox, but not specific containers
• #895 Even pod spreading across failure domains
• #950 Add pod-startup liveness-probe holdoff for
slow-starting pods
• #964 Extending RequestedToCapacityRatio priority
function to support resource bin packing of
extended resources
• #894 RuntimeClass scheduling – Beta
• #689 Support GMSA for Windows workloads - Beta

23. References and Kubernetes
1.17 updates link
• https://github.com/kubernetes/kubernet
es/blob/master/CHANGELOG-1.17.md
• https://sysdig.com/blog/whats-new-
kubernetes-1-16/
• https://www.youtube.com/watch?v=q9E
s0mXQlOc
Big Thanks to Awesome Kubernetes Release Team :
https://github.com/kubernetes/sig-
release/blob/master/releases/release-1.16/release_team.md

24. New in
Rancher 2.3
• Reuse Kubernetes configurations across all their cluster
deployments
• First Kubernetes management platform to deliver GA
support for Windows Containers and Kubernetes with
Windows worker nodes
• Gsuite integration
• Istio from Rancher
• Kiali dashboards for traffic and telemetry visualization
• Jaeger for tracing
• Prometheus and Grafana for observability

25. • Thank you• Thank you