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feat: make virtual-node kubelet port configurable via VK_KUBELET_PORT #32

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Merged
CMGS merged 1 commit into from
Jul 12, 2026
+21 −10
Merged

feat: make virtual-node kubelet port configurable via VK_KUBELET_PORT #32

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1 change: 1 addition & 0 deletions README.md
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Original file line number Diff line number Diff line change
Expand Up @@ -191,6 +191,7 @@ If the ICMP raw socket cannot be opened — typically because the binary is runn
| `VK_PROVIDER_ID` | unset | Cloud-provider ProviderID for the virtual node (e.g. `gce://<project>/<zone>/<instance>`). Prevents cloud node lifecycle controllers from deleting the virtual node. |
| `VK_TLS_CERT` | `/etc/cocoon/vk/tls/vk-kubelet.crt` | Path to the kubelet serving TLS certificate. |
| `VK_TLS_KEY` | `/etc/cocoon/vk/tls/vk-kubelet.key` | Path to the kubelet serving TLS private key. |
| `VK_KUBELET_PORT` | `10250` | Port the virtual node's kubelet API listens on and advertises. Override when a real kubelet on the same host already owns `:10250` (e.g. a co-located k3s server node). |
| `VK_METRICS_ADDR` | `:9091` | Plain-HTTP prometheus listener. |
| `VK_RESERVE_PERCENT` | `20` | Percentage of host resources reserved for the host OS (0-100). Allocatable = Capacity × (100 - reserve) / 100. |
| `VK_NODE_CPU` | auto-detected | Override CPU capacity (auto: `runtime.NumCPU()`). |
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30 changes: 20 additions & 10 deletions main.go
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Original file line number Diff line number Diff line change
Expand Up @@ -11,6 +11,7 @@ import (
"os"
"os/signal"
"slices"
"strconv"
"strings"
"syscall"
"time"
Expand Down Expand Up @@ -51,12 +52,12 @@ const (
defaultMetricsAddr = ":9091"
defaultOrphanPolicy = string(provider.OrphanDestroy)

defaultTLSCert = "/etc/cocoon/vk/tls/vk-kubelet.crt"
defaultTLSKey = "/etc/cocoon/vk/tls/vk-kubelet.key"
kubeletAPIPort = 10250
endpointPatchWait = 5 * time.Second
endpointPatchRetry = 2 * time.Second
shutdownTimeout = 10 * time.Second
defaultTLSCert = "/etc/cocoon/vk/tls/vk-kubelet.crt"
defaultTLSKey = "/etc/cocoon/vk/tls/vk-kubelet.key"
defaultKubeletAPIPort = 10250
endpointPatchWait = 5 * time.Second
endpointPatchRetry = 2 * time.Second
shutdownTimeout = 10 * time.Second
)

func main() {
Expand Down Expand Up @@ -153,7 +154,7 @@ func main() {
cfg.Node.Status.Capacity = nodeCapacity
cfg.Node.Status.Allocatable = nodeAllocatable
cfg.Node.Status.DaemonEndpoints = corev1.NodeDaemonEndpoints{
KubeletEndpoint: corev1.DaemonEndpoint{Port: kubeletAPIPort},
KubeletEndpoint: corev1.DaemonEndpoint{Port: kubeletAPIPort()},
}
if providerID != "" {
cfg.Node.Spec.ProviderID = providerID
Expand Down Expand Up @@ -195,7 +196,7 @@ func main() {
metricsServer := commonhttpx.NewServer(metricsAddr, metricsMux)

go func() {
logger.Infof(signalCtx, "vk-cocoon node %s kubelet API on :%d", nodeName, kubeletAPIPort)
logger.Infof(signalCtx, "vk-cocoon node %s kubelet API on :%d", nodeName, kubeletAPIPort())
if err := n.Run(signalCtx); err != nil {
logger.Fatalf(signalCtx, err, "virtual-kubelet node exited")
}
Expand Down Expand Up @@ -263,9 +264,18 @@ func buildProvider(ctx context.Context, opts buildOpts) (*cocoon.Provider, error
return p, nil
}

// kubeletAPIPort is overridable via VK_KUBELET_PORT so a co-located kubelet (e.g. k3s) can keep :10250.
func kubeletAPIPort() int32 {
if p, err := strconv.ParseUint(os.Getenv("VK_KUBELET_PORT"), 10, 16); err == nil && p > 0 {
return int32(p)
}
return defaultKubeletAPIPort
}

func withHandler(h http.Handler) nodeutil.NodeOpt {
return func(cfg *nodeutil.NodeConfig) error {
cfg.Handler = h
cfg.HTTPListenAddr = fmt.Sprintf(":%d", kubeletAPIPort())
return nil
}
}
Expand All @@ -287,7 +297,7 @@ func patchKubeletEndpoint(ctx context.Context, clientset kubernetes.Interface, n
continue
}
nodeObj.Status.DaemonEndpoints = corev1.NodeDaemonEndpoints{
KubeletEndpoint: corev1.DaemonEndpoint{Port: kubeletAPIPort},
KubeletEndpoint: corev1.DaemonEndpoint{Port: kubeletAPIPort()},
}
if _, err := clientset.CoreV1().Nodes().UpdateStatus(ctx, nodeObj, metav1.UpdateOptions{}); err != nil {
logger.Errorf(ctx, err, "patch daemon endpoints attempt %d", attempt)
Expand All @@ -296,7 +306,7 @@ func patchKubeletEndpoint(ctx context.Context, clientset kubernetes.Interface, n
}
continue
}
logger.Infof(ctx, "node %s kubelet endpoint set to :%d", nodeName, kubeletAPIPort)
logger.Infof(ctx, "node %s kubelet endpoint set to :%d", nodeName, kubeletAPIPort())
return
}
}
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