Kubeadm upgrade apply failed when the etcd-data is not /var/lib/etcd

[alfadb]

Is this a BUG REPORT or FEATURE REQUEST?

BUG REPORT

Versions

kubeadm version (use kubeadm version):

kubeadm version: &version.Info{Major:"1", Minor:"30", GitVersion:"v1.30.0", GitCommit:"7c48c2bd72b9bf5c44d21d7338cc7bea77d0ad2a", GitTreeState:"clean", BuildDate:"2024-04-17T17:34:08Z", GoVersion:"go1.22.2", Compiler:"gc", Platform:"linux/amd64"}

Environment:

• Kubernetes version (use kubectl version): v1.29.3
• Cloud provider or hardware configuration:
• OS (e.g. from /etc/os-release): Debian GNU/Linux 12 (bookworm)
• Kernel (e.g. uname -a): Linux host 6.5.13-5-pve x86_64 GNU/Linux
• Container runtime (CRI) (e.g. containerd, cri-o): containerd
• Container networking plugin (CNI) (e.g. Calico, Cilium): flannel

What happened?

My etcd dir on host is not /var/lib/etcd, when I execute sudo kubeadm upgrade apply v1.30.0, I got this error:

[upgrade/config] Making sure the configuration is correct:
[preflight] Running pre-flight checks.
[upgrade/config] Reading configuration from the cluster...
[upgrade/config] FYI: You can look at this config file with 'kubectl -n kube-system get cm kubeadm-config -o yaml'
[upgrade] Running cluster health checks
[upgrade/version] You have chosen to change the cluster version to "v1.30.0"
[upgrade/versions] Cluster version: v1.29.3
[upgrade/versions] kubeadm version: v1.30.0
[upgrade] Are you sure you want to proceed? [y/N]: y
[upgrade/prepull] Pulling images required for setting up a Kubernetes cluster
[upgrade/prepull] This might take a minute or two, depending on the speed of your internet connection
[upgrade/prepull] You can also perform this action in beforehand using 'kubeadm config images pull'
[upgrade/apply] Upgrading your Static Pod-hosted control plane to version "v1.30.0" (timeout: 5m0s)...
[upgrade/etcd] Upgrading to TLS for etcd
[upgrade/apply] FATAL: failed to back up etcd data, output: "cp: cannot stat '/var/lib/etcd': No such file or directory\n": exit status 1
To see the stack trace of this error execute with --v=5 or higher

My /etc/kubernetes/manifests/etcd.yaml file like this:

apiVersion: v1
kind: Pod
metadata:
  annotations:
    kubeadm.kubernetes.io/etcd.advertise-client-urls: https://192.168.50.3:2379
  creationTimestamp: null
  labels:
    component: etcd
    tier: control-plane
  name: etcd
  namespace: kube-system
spec:
  ...
  volumes:
  - hostPath:
      path: /etc/kubernetes/pki/etcd
      type: DirectoryOrCreate
    name: etcd-certs
  - hostPath:
      path: /main/data/etcd
      type: DirectoryOrCreate
    name: etcd-data

I Changed the etcd-data's path to /main/data/etcd.

What you expected to happen?

Correct upgrade

How to reproduce it (as minimally and precisely as possible)?

Change host /var/lib/etcd to another path.

Anything else we need to know?

None.

[neolit123]

My etcd dir on host is not /var/lib/etcd, when I execute sudo kubeadm upgrade apply v1.30.0, I got this error:

this is not supported.

a lot of kubeadm paths on the hosts are hardcoded, including /etc/kubernetes, /var/lib/etcd, /var/lib/kubelet

symlinks is what we recommend to users, but there are no plans to support customization of these dirs.