The upgrade rancher dilemna

OK.

It's been awhile since I have not upgraded Rancher and the K3S cluster infra and I think it's maybe thge good time to upgrade my infra to be up to date.

Problem is that I fear this upgrade because I went in the past into some big issues like the rancher webgui not accessible and haf to restore back all the vms of the infra.

But well, that's not a good reason to not to upgrade!

So, I have decided to make it more clean and have a way to:

Backup
Plan
Test
Do
Validate

the update tasks.

This time I really be organized and do this update once for all!

So, my initial plan is to use rancher 2.7.5 because the 2.7.6 and the 2.7.7 seems to be in RC with and not sure exactly what is the difference between the 2...

Anyway!

Let's have a look at my current setup:

3 master nodes (centos 7.9)
3 workers (centos 7.9)
kube-vip used as the VIP manager

Current version of K3s (I used k3sup to install it):

[root@node-1 ~]# kubectl get nodes -o wide
NAME STATUS ROLES AGE VERSION INTERNAL-IP EXTERNAL-IP OS-IMAGE KERNEL-VERSION CONTAINER-RUNTIME
node-1 Ready control-plane,etcd,master 2y142d v1.21.12+k3s1 192.168.2.100 <none> CentOS Linux 7 (Core) 3.10.0-1160.88.1.el7.x86_64 containerd://1.4.13-k3s1
node-2 Ready control-plane,etcd,master 442d v1.21.12+k3s1 192.168.2.101 <none> CentOS Linux 7 (Core) 3.10.0-1160.49.1.el7.x86_64 containerd://1.4.13-k3s1
node-3 Ready control-plane,etcd,master 431d v1.21.12+k3s1 192.168.2.102 <none> CentOS Linux 7 (Core) 3.10.0-1160.88.1.el7.x86_64 containerd://1.4.13-k3s1
worker-1 Ready <none> 2y142d v1.21.12+k3s1 192.168.2.103 <none> CentOS Linux 7 (Core) 3.10.0-1160.49.1.el7.x86_64 containerd://1.4.13-k3s1
worker-2 Ready <none> 2y142d v1.21.12+k3s1 192.168.2.104 <none> CentOS Linux 7 (Core) 3.10.0-1160.88.1.el7.x86_64 containerd://1.4.13-k3s1
worker-3 Ready <none> 356d v1.21.12+k3s1 192.168.2.105 <none> CentOS Linux 7 (Core) 3.10.0-1160.49.1.el7.x86_64 containerd://1.4.13-k3s1