Kubernetes 1.16 - how to upgrade and not break anything

Today, September 18, the next version of Kubernetes is released - 1.16. As always, we will find many improvements and new products. But I would like to draw your attention to the sections of the Action Required file CHANGELOG-1.16.md . These sections publish changes that may interrupt the operation of your application, cluster maintenance tools, or require changes to configuration files.

In general, they require manual intervention ...

Let's start right away with a change that is likely to affect everyone who has been working with kubernetes for a long time. The Kubernetes API has stopped supporting legacy versions of the resource API.

If anyone did not know, or forgot ...

The version of the resource API is indicated in the manifest in the apiVersion: apps/v1

field

Namely:

Resource type	Old version	What you need to replace
All resources	apps / v1beta1 apps / v1beta2	apps / v1
deployments daemonset replicaset	extensions / v1beta1	apps / v1
networkpolicies	extensions / v1beta1	networking.k8s.io/v1
podsecuritypolicies	extensions / v1beta1	policy / v1beta1

I also want to note that for objects like Ingress

apiVersion

also changed to networking.k8s.io/v1beta1

. The old extensions/v1beta1

still supported, but there is a good reason to update this version in manifests at the same time.

There are a lot of changes in various system labels (Node labels) that are installed on nodes.

Kubelet was forbidden to set arbitrary labels (before they could be set via the kubelet --node-labels

launch keys), they left only this list of allowed ones :

 kubernetes.io/hostname kubernetes.io/instance-type kubernetes.io/os kubernetes.io/arch beta.kubernetes.io/instance-type beta.kubernetes.io/os beta.kubernetes.io/arch failure-domain.beta.kubernetes.io/zone failure-domain.beta.kubernetes.io/region failure-domain.kubernetes.io/zone failure-domain.kubernetes.io/region [*.]kubelet.kubernetes.io/* [*.]node.kubernetes.io/*

The labels beta.kubernetes.io/metadata-proxy-ready

, beta.kubernetes.io/masq-agent-ds-ready

and beta.kubernetes.io/kube-proxy-ds-ready

no longer added to new nodes, and various additional components began to use slightly different labels as a node selector:

Component	Old label	Current tag
kube-proxy	beta.kubernetes.io/kube-proxy-ds-ready	node.kubernetes.io/kube-proxy-ds-ready
ip-mask-agent	beta.kubernetes.io/masq-agent-ds-ready	node.kubernetes.io/masq-agent-ds-ready
metadata-proxy	beta.kubernetes.io/metadata-proxy-ready	cloud.google.com/metadata-proxy-ready

kubeadm now removes the bootstrap-kubelet.conf

initial configuration file. If your tools accessed this file, then switch to using kubelet.conf

, which stores the current access settings.

Cadvisor no longer gives the pod_name

and container_name

metrics, if you used them in Prometheus, go to the pod

and container

metrics, respectively.

The keys were removed with the command line:

Component	Key removed
hyperkube	--make-symlink
kube-proxy	--resource-container

Scheduler began to use the v1beta1 Event API version. If you use third-party tools to interact with the Event API, switch to the current version.

A moment of humor. In the process of preparing release 1.16, the following changes were made:

removed annotation scheduler.alpha.kubernetes.io/critical-pod

in version v1.16.0-alpha.1
returned annotation scheduler.alpha.kubernetes.io/critical-pod

in version v1.16.0-alpha.2
removed annotation scheduler.alpha.kubernetes.io/critical-pod

in version v1.16.0-beta.1

Use the spec.priorityClassName

field to indicate the importance of the hearth.

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