From cd859cc9c45b20781839afca4518a19882281942 Mon Sep 17 00:00:00 2001
From: Wilfried OLLIVIER <wollivier@fdn.fr>
Date: Thu, 5 Aug 2021 14:44:58 +0200
Subject: [PATCH] Add k8s upgrade

---
 src/SUMMARY.md         |  1 +
 src/ops/k8s/upgrade.md | 63 ++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 64 insertions(+)
 create mode 100644 src/ops/k8s/upgrade.md

diff --git a/src/SUMMARY.md b/src/SUMMARY.md
index bafc855..afb15ca 100644
--- a/src/SUMMARY.md
+++ b/src/SUMMARY.md
@@ -32,6 +32,7 @@
 - [Ops](./ops/main.md)
   - [k8s](./ops/k8s/main.md)
     - [kubectl](./ops/k8s/kubectl.md)
+    - [upgrade](./ops/k8s/upgrade.md)
   - [macOS](./ops/macos/main.md)
     - [iterm](./ops/macos/iterm.md)
   - [GNU/Linux](./ops/gnulinux/main.md)
diff --git a/src/ops/k8s/upgrade.md b/src/ops/k8s/upgrade.md
new file mode 100644
index 0000000..0876332
--- /dev/null
+++ b/src/ops/k8s/upgrade.md
@@ -0,0 +1,63 @@
+# Cluster Upgrade
+
+## Versions
+
+`vMajor.Minor.Patch` semantic versioning
+
+K8S compatibility is as follow : current and n-2 version are supported.
+
+**Always upgrade minor to minor releases**.
+
+## kubeadm
+
+### Check latest/upgradable version
+
+```shell
+kubeadm upgrade plan
+```
+
+## Master node upgrade
+
+### Drain and mark it at Unschedulable
+
+```shell
+kubectl drain master
+```
+
+`kubectl get nodes` to verify that master node is unschedulable
+
+### kubeadm update
+
+```shell
+apt install kubeadm=X.Y.Z-00
+```
+
+`kubeadm version` to ensure version number
+
+### Node update
+
+```shell
+kubeadm upgrade apply vX.Y.Z
+```
+
+`kubectl version` to validate
+
+### Update kubelet
+
+```shell
+apt install kubelet=X.Y.Z-00
+```
+
+`kubectl get nodes` to validate
+
+### Mark master node as schedulable
+
+```shell
+kubectl uncordon master
+```
+
+## Worker nodes upgrade
+
+Repeat the same actions done on master for each worker node
+
+🎉