Kubernetes 1.20

[zoetrope]

Description

Update Neco for Kubernetes 1.20.
For reference, epic for 1.19 was #1146.

Submit conformance test results for Kubernetes 1.20 using sonobuoy 0.20.x.
https://github.com/cncf/k8s-conformance/blob/master/instructions.md#uploading

Requirements for readiness:

• No critical problems.
• Applications running on neco are guaranteed working with kubernetes 1.20.

Initiative / Motivation

We should update Kubernetes for each minor release.

Technical information

What's new in Kubernetes 1.20 by Sysdig.

Apply the following patches:

• kube-proxy: track serving/terminating conditions in endpoints cache kubernetes/kubernetes#96371
• manager#syncPod should cover reconciliation kubernetes/kubernetes#89155
• Ipvs: non-local access to externalTrafficPolicy:Local kubernetes/kubernetes#97081

Check and convert the following deprecated APIs storage version. ( https://github.com/cybozu-private/neco-ops/issues/791 )

• CustomResourceDefinition
• APIService
• CSIDriver

We should evaluate CronJobControllerV2 ( https://github.com/kubernetes/enhancements/tree/master/keps/sig-apps/19-Graduate-CronJob-to-Stable )

We should check and rename deprecated node-role labels. ( kubernetes/enhancements#2067 )

In an effort to move away from offensive wording, node-role.kubernetes.io/master is being renamed to node-role.kubernetes.io/control-plane.

We may use the following features in the future when it is graduated to beta.

#1435 Support of mixed protocols in Services with type=LoadBalancer
#1864 Optionally Disable NodePorts for Service Type=LoadBalancer

We should check and fix exec probe timeouts. ( kubernetes/enhancements#1972 )

The containerd team is working on supporting PID NamespaceMode_TARGET in containerd/containerd#5203. Apply this patch to our containerd and see if kubectl debug with --target works properly.

Scope and goal

Define what is a must-have for launch and in-scope. Keep this section fluid and dynamic until you lock-in priority during planning.

• Update cri-tools to 1.20.x
• Update contained
  • Re-evaluate kubectl alpha debug with --target if it can attach the target process namespace.
• Update metrics-server
• Update kube-state-metrics
• Update CoreDNS to the latest stable version
• Update client libraries for Coil
• Update client libraries for programs in neco-containers:
  • bmc-reverse-proxy
  • neco-admission
  • local-pv-provisioner
  • machines-endpoints
• Follow the k8s metrics name change

Definition of ready

• The epic owner is assigned.
• Initiatives and scopes are clearly stated.
• Feasibility is proved by PoC or scrutiny.
• All necessary issues that complete this epic are created.
• At least three people agree on making this ready.