Kubernetes 1.20

The Raddest Release

raddest: adjective, Slang. excellent; wonderful; cool:

11 enhancements ==> stable

15 enhancements ==> beta

16 enhancements ==> alpha.

42 enhancements

Container Runtime Interface moved to stable

https://kubernetes.io/blog/2016/12/container-runtime-interface-cri-in-kubernetes/

Dockershim is deprecated

Docker as an underlying RUNTIME is being deprecated.

Docker still an option.

Open Container Initiative (OCI) Docker, CRI-O, containerd

https://opencontainers.org/

IPv4/IPv6 dual-stack

Still alpha feature
Cluster IP Service can have both IPv4 & IPv6
```
.spec.ipFamilyPolicy 
```
- Move from single to dual stack
- Move from dual to single stack

go1.15.5 is now used in K8s

kubectl

kubectl debug #beta

kubectl alpha debug ...

kubectl debug #beta

kubectl alpha debug ...

kubectl debug ...

kubectl code is decoupled

https://github.com/kubernetes/kubectl

k8s.io/kubernetes/pkg/kubectl

Avoid dependencies on K8s internal code
Make it easy for external projects to reuse code from kubectl

https://github.com/kubernetes/kubernetes/tree/master/staging

Graceful Node Shutdown

Alpha feature
Allows graceful termination of pods during a system shutdown
kubelet is aware of system status

kubelet exec probe timeouts

Probes:

initialDelaySeconds
periodSeconds
successThreshold
failureThreshold
timeoutSeconds

kubelet exec probe timeouts

Turn it off via feature gate:

ExecProbeTimeout:False

Probes:

initialDelaySeconds
periodSeconds
successThreshold
failureThreshold
timeoutSeconds

startupProbe graduates to stable

hold other probes before my app is really ready to be checked
Avoid pod to be killed very early
Avoid pod to be left as dead for a long time

Tracking Terminating Endpoints in the EndpointSlice API

EndpointSlice API to track endpoints being terminated
no need to watch the pods
Make smarter decisions

Networking

Different protocols in the same service definition with type=loadbalancer

Two load balancers for TCP & UDP traffic

Different protocols in the same service definition with type=loadbalancer

alpha feature
both UPD & TCP is supported on the same port

Two load balancers for TCP & UDP traffic

Different protocols in the same service definition with type=loadbalancer

alpha feature
both UPD & TCP is supported on the same port

Two load balancers for TCP & UDP traffic

apiVersion: v1
kind: Service
metadata:
  name: mixed-protocol
spec:
  type: LoadBalancer
  ports:
    - name: dns-udp
      port: 53
      protocol: UDP
    - name: dns-tcp
      port: 53
      protocol: TCP
  selector:
    app: my-dns-server

Optionally Disable NodePorts for Service type=LoadBalancer

alpha feature
```
allocateLoadBalancerNodePort: *bool
```

Getting rid of non-inclusive language in kubeadm

master taint is replaced by controlplane

CronJob (previously ScheduledJobs) graduates to stable

Thank you