Files
monok8s/clitools/pkg/node/kubeadm_compat.go

109 lines
3.2 KiB
Go

package node
import (
"context"
"errors"
"fmt"
"os"
"strings"
"k8s.io/klog/v2"
"example.com/monok8s/pkg/system"
)
const kubeadmUpgradeNodeHostnameBugFixedIn = "v1.35.0"
// COMPAT(kubeadm-upgrade-node-hostname)
// Affects: Kubernetes/kubeadm < v1.35.0
// Upstream: kubernetes/kubeadm#3244, kubernetes/kubernetes#134319
// RemoveWhen: minimum supported Kubernetes version >= v1.35.0
//
// Affected kubeadm versions can derive the target Node name for
// `kubeadm upgrade node` from the local OS hostname instead of the existing
// kubeadm NodeRegistration / kubelet --hostname-override state.
func needsKubeadmUpgradeNodeHostnameWorkaround(kubeadmVersion string) bool {
lt, err := versionLt(kubeadmVersion, kubeadmUpgradeNodeHostnameBugFixedIn)
if err != nil {
klog.Warningf(
"could not parse kubeadm version %q; enabling kubeadm upgrade node hostname workaround: %v",
kubeadmVersion,
err,
)
return true
}
return lt
}
// runWithTemporaryHostname works around kubernetes/kubeadm#3244, fixed by
// kubernetes/kubernetes#134319 in Kubernetes v1.35.0.
//
// Affected kubeadm versions can derive the target Node name for
// `kubeadm upgrade node` from the local OS hostname instead of the existing
// kubeadm NodeRegistration / kubelet --hostname-override state. That breaks
// valid setups where the machine hostname differs from the Kubernetes Node
// name: kubeadm may authenticate as one node but try to get/patch another Node,
// and the Node authorizer correctly rejects it.
//
// Keep this workaround scoped to affected kubeadm versions only. Set the
// temporary hostname to the Kubernetes Node name, run kubeadm, then restore the
// configured machine hostname immediately afterward.
func runWithTemporaryHostname(ctx context.Context, nctx *NodeContext, fn func(context.Context) error) error {
if nctx == nil {
return errors.New("node context is nil")
}
temporaryHostname := strings.TrimSpace(nctx.Config.Spec.NodeName)
if temporaryHostname == "" {
return errors.New("temporary hostname is required")
}
originalHostname, err := os.Hostname()
if err != nil {
return fmt.Errorf("get current hostname: %w", err)
}
if originalHostname == temporaryHostname {
return fn(ctx)
}
restoreHostname := strings.TrimSpace(nctx.Config.Spec.Network.Hostname)
if restoreHostname == "" {
restoreHostname = originalHostname
}
klog.Warningf(
"temporarily changing hostname for kubeadm upgrade node: current=%q temporary=%q restore=%q",
originalHostname,
temporaryHostname,
restoreHostname,
)
if err := system.SetHostname(temporaryHostname); err != nil {
return fmt.Errorf("set temporary hostname to %q: %w", temporaryHostname, err)
}
defer func() {
if err := system.SetHostname(restoreHostname); err != nil {
klog.Errorf("failed to restore hostname to %q: %v", restoreHostname, err)
}
}()
return fn(ctx)
}
// COMPAT(kubeadm-upgrade-node-hostname)
// RemoveWhen: minimum supported Kubernetes version >= v1.35.0
func runKubeadmUpgradeNodeWithCompat(
ctx context.Context,
nctx *NodeContext,
kubeadmVersion string,
fn func(context.Context) error,
) error {
if needsKubeadmUpgradeNodeHostnameWorkaround(kubeadmVersion) {
return runWithTemporaryHostname(ctx, nctx, fn)
}
return fn(ctx)
}