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Kubernetes Upgrade Notes

Prerequisite​

  1. Upgrade to the latest minor release. e.g. you are using 1.9.3, upgrade to latest 1.9.x
  2. Read the CHANGELOG of the target version. Watch out for sections:
  • Action Required
  • Deprecations and Removals
  1. Consider etcd backup.

Upgrade​

  • etcd per recommended & supported version.
  • CNI and/or CoreDNS? Drain node-by-node.
  • kubectl
  • control nodes kubernetes binaries e.g. kube-apiserver, kube-controller-manager, kube-scheduler, etc.
  • worker nodes e.g. kubelet, kube-proxy, CNI, etc.

1.14 -> 1.15 Case-study​

For target version CHANGELOG, the minimal MUST read:

There's also searchable release notes: https://relnotes.k8s.io/?releaseVersions=1.15.0

Deprecated API versions in 1.15:

  • Ingress: migrate to networking.k8s.io/v1beta1
  • NetworkPolicy: migrate to networking.k8s.io/v1
  • PodSecurityPolicy: migrate to policy/v1beta1
  • DaemonSet: migrate to apps/v1
  • Deployment: migrate to apps/v1
  • ReplicaSet: migrate to apps/v1
  • PriorityClass: migrate to scheduling.k8s.io/v1

Check currently used objects:

kubectl get ingresses.extensions -A
kubectl get ingress.networking.k8s.io -A

kubectl get networkpolicies.extensions -A
kubectl get networkpolicies.networking.k8s.io -A

kubectl get podsecuritypolicies.extensions -A
kubectl get podsecuritypolicies.policy -A

kubectl get daemonsets.extensions -A
kubectl get daemonsets.apps -A

kubectl get deployment.extensions -A
kubectl get deployment.apps -A

kubectl get replicasets.extensions -A
kubectl get replicasets.apps -A

kubectl get priorityclasses.scheduling.k8s.io -A

Cluster List​

DigitalOcean has a CLI tool, clusterlint and a knowledge-base for common issues & fixes: https://www.digitalocean.com/docs/kubernetes/resources/clusterlint-errors/

Resources​