The k3s system-upgrade controller is a fantastic tool for upgrading k3s automatically. It has done a fantastic job for me every time I’ve used it. Today I ran it on a cluster that needed to upgrade several minors and I learned that the controller does not pick up on changes to the channel url if you change from minor to minor.

The solution I came up with was to name the plan with the version it supports. Then on each patch upgrade, change both the plan name and the channel. I use gitops with argocd, it automcatically cleaned up old plans, created new plans, and the system-upgrade-controller picked up the plan and started applying immediately.

# Server plan
apiVersion: upgrade.cattle.io/v1
kind: Plan
metadata:
name: server-plan-v1.33 # <- This is important if you want to change the channel name
namespace: system-upgrade
spec:
concurrency: 1
cordon: true
nodeSelector:
matchExpressions:
- key: node-role.kubernetes.io/control-plane
operator: In
values:
- "true"
serviceAccountName: system-upgrade
upgrade:
image: rancher/k3s-upgrade
channel: https://update.k3s.io/v1-release/channels/v1.33
---
# Agent plan
apiVersion: upgrade.cattle.io/v1
kind: Plan
metadata:
name: agent-plan-v1.33 # <- This is important if you want to change the channel name
namespace: system-upgrade
spec:
concurrency: 1
cordon: true
nodeSelector:
matchExpressions:
- key: node-role.kubernetes.io/control-plane
operator: DoesNotExist
prepare:
args:
- prepare
- server-plan
image: rancher/k3s-upgrade
serviceAccountName: system-upgrade
upgrade:
image: rancher/k3s-upgrade
channel: https://update.k3s.io/v1-release/channels/v1.33

I’d love to see a better way if you have a way to upgrade through minors, or manually control the minor of your cluster let me know.