From 9c7fcaa827263eb0fd89f352c6003ed78df768b5 Mon Sep 17 00:00:00 2001 From: Erik Sundell Date: Tue, 7 May 2024 17:38:10 +0200 Subject: [PATCH] docs: iterate on version skew text to better introduce version skew --- .../howto/upgrade-cluster/k8s-version-skew.md | 22 +++++++++---------- 1 file changed, 11 insertions(+), 11 deletions(-) diff --git a/docs/howto/upgrade-cluster/k8s-version-skew.md b/docs/howto/upgrade-cluster/k8s-version-skew.md index 008101e743..d8cc29042e 100644 --- a/docs/howto/upgrade-cluster/k8s-version-skew.md +++ b/docs/howto/upgrade-cluster/k8s-version-skew.md @@ -1,22 +1,22 @@ (upgrade-cluster:k8s-version-skew)= # About Kubernetes' version skew policy -When we upgrade our Kubernetes clusters, we upgrade the k8s control plane (k8s -api-server etc.), the cloud providers managed workloads (`calico-node` etc.), -and the k8s node's software (`kubelet` etc.). Since these upgrades aren't done -at the exact same time, there are known constraints on how the various versions -can [_skew_] in relation to each other. +Kubernetes clusters' software running on various machines is designed to work +even when various components gets upgraded independently of each other - at +least as long as the components don't get too mismatched versions. -When we upgrade, we are practically constrained by [Kubernetes' version skew -policy] in the following ways: +The _tolerated mismatch of versions between k8s software components_ is called +the supported _version skew_, and Kubernetes provides a [version skew policy] +about this. + +Practically for us when upgrading k8s clusters, we need to know that: 1. Highly available clusters' control planes can only be upgraded one minor version at a time (`api-server` requirement). - All of our new clusters and most of our old clusters are regional, so our - documentation assumes we need to respect this constraint. + All of our new clusters and most of our old clusters are highly available, so + our documentation assumes we need to respect this constraint. 2. Nodes' k8s version must not be newer than the control plane, and be at most three minor versions older (`kubelet` requirement). -[_skew_]: https://www.industrialempathy.com/posts/version-skew/ -[Kubernetes' version skew policy]: https://kubernetes.io/releases/version-skew-policy/#supported-version-skew +[version skew policy]: https://kubernetes.io/releases/version-skew-policy/#supported-version-skew