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tailscale/cmd/k8s-operator/svc.go

281 lines
9.6 KiB
Go

// Copyright (c) Tailscale Inc & AUTHORS
// SPDX-License-Identifier: BSD-3-Clause
//go:build !plan9
package main
import (
"context"
"fmt"
"net/netip"
"strings"
"sync"
"go.uber.org/zap"
"golang.org/x/exp/slices"
corev1 "k8s.io/api/core/v1"
apierrors "k8s.io/apimachinery/pkg/api/errors"
"k8s.io/apimachinery/pkg/types"
"sigs.k8s.io/controller-runtime/pkg/client"
"sigs.k8s.io/controller-runtime/pkg/reconcile"
"tailscale.com/util/clientmetric"
"tailscale.com/util/set"
)
type ServiceReconciler struct {
client.Client
ssr *tailscaleSTSReconciler
logger *zap.SugaredLogger
isDefaultLoadBalancer bool
mu sync.Mutex // protects following
// managedIngressProxies is a set of all ingress proxies that we're
// currently managing. This is only used for metrics.
managedIngressProxies set.Slice[types.UID]
// managedEgressProxies is a set of all egress proxies that we're currently
// managing. This is only used for metrics.
managedEgressProxies set.Slice[types.UID]
}
var (
// gaugeEgressProxies tracks the number of egress proxies that we're
// currently managing.
gaugeEgressProxies = clientmetric.NewGauge("k8s_egress_proxies")
// gaugeIngressProxies tracks the number of ingress proxies that we're
// currently managing.
gaugeIngressProxies = clientmetric.NewGauge("k8s_ingress_proxies")
)
func childResourceLabels(name, ns, typ string) map[string]string {
// You might wonder why we're using owner references, since they seem to be
// built for exactly this. Unfortunately, Kubernetes does not support
// cross-namespace ownership, by design. This means we cannot make the
// service being exposed the owner of the implementation details of the
// proxying. Instead, we have to do our own filtering and tracking with
// labels.
return map[string]string{
LabelManaged: "true",
LabelParentName: name,
LabelParentNamespace: ns,
LabelParentType: typ,
}
}
func (a *ServiceReconciler) Reconcile(ctx context.Context, req reconcile.Request) (_ reconcile.Result, err error) {
logger := a.logger.With("service-ns", req.Namespace, "service-name", req.Name)
logger.Debugf("starting reconcile")
defer logger.Debugf("reconcile finished")
svc := new(corev1.Service)
err = a.Get(ctx, req.NamespacedName, svc)
if apierrors.IsNotFound(err) {
// Request object not found, could have been deleted after reconcile request.
logger.Debugf("service not found, assuming it was deleted")
return reconcile.Result{}, nil
} else if err != nil {
return reconcile.Result{}, fmt.Errorf("failed to get svc: %w", err)
}
targetIP := a.tailnetTargetAnnotation(svc)
if !svc.DeletionTimestamp.IsZero() || !a.shouldExpose(svc) && targetIP == "" {
logger.Debugf("service is being deleted or is (no longer) referring to Tailscale ingress/egress, ensuring any created resources are cleaned up")
return reconcile.Result{}, a.maybeCleanup(ctx, logger, svc)
}
return reconcile.Result{}, a.maybeProvision(ctx, logger, svc)
}
// maybeCleanup removes any existing resources related to serving svc over tailscale.
//
// This function is responsible for removing the finalizer from the service,
// once all associated resources are gone.
func (a *ServiceReconciler) maybeCleanup(ctx context.Context, logger *zap.SugaredLogger, svc *corev1.Service) error {
ix := slices.Index(svc.Finalizers, FinalizerName)
if ix < 0 {
logger.Debugf("no finalizer, nothing to do")
a.mu.Lock()
defer a.mu.Unlock()
a.managedIngressProxies.Remove(svc.UID)
a.managedEgressProxies.Remove(svc.UID)
gaugeIngressProxies.Set(int64(a.managedIngressProxies.Len()))
gaugeEgressProxies.Set(int64(a.managedEgressProxies.Len()))
return nil
}
if done, err := a.ssr.Cleanup(ctx, logger, childResourceLabels(svc.Name, svc.Namespace, "svc")); err != nil {
return fmt.Errorf("failed to cleanup: %w", err)
} else if !done {
logger.Debugf("cleanup not done yet, waiting for next reconcile")
return nil
}
svc.Finalizers = append(svc.Finalizers[:ix], svc.Finalizers[ix+1:]...)
if err := a.Update(ctx, svc); err != nil {
return fmt.Errorf("failed to remove finalizer: %w", err)
}
// Unlike most log entries in the reconcile loop, this will get printed
// exactly once at the very end of cleanup, because the final step of
// cleanup removes the tailscale finalizer, which will make all future
// reconciles exit early.
logger.Infof("unexposed service from tailnet")
a.mu.Lock()
defer a.mu.Unlock()
a.managedIngressProxies.Remove(svc.UID)
a.managedEgressProxies.Remove(svc.UID)
gaugeIngressProxies.Set(int64(a.managedIngressProxies.Len()))
gaugeEgressProxies.Set(int64(a.managedEgressProxies.Len()))
return nil
}
// maybeProvision ensures that svc is exposed over tailscale, taking any actions
// necessary to reach that state.
//
// This function adds a finalizer to svc, ensuring that we can handle orderly
// deprovisioning later.
func (a *ServiceReconciler) maybeProvision(ctx context.Context, logger *zap.SugaredLogger, svc *corev1.Service) error {
hostname, err := nameForService(svc)
if err != nil {
return err
}
if !slices.Contains(svc.Finalizers, FinalizerName) {
// This log line is printed exactly once during initial provisioning,
// because once the finalizer is in place this block gets skipped. So,
// this is a nice place to tell the operator that the high level,
// multi-reconcile operation is underway.
logger.Infof("exposing service over tailscale")
svc.Finalizers = append(svc.Finalizers, FinalizerName)
if err := a.Update(ctx, svc); err != nil {
return fmt.Errorf("failed to add finalizer: %w", err)
}
}
crl := childResourceLabels(svc.Name, svc.Namespace, "svc")
var tags []string
if tstr, ok := svc.Annotations[AnnotationTags]; ok {
tags = strings.Split(tstr, ",")
}
sts := &tailscaleSTSConfig{
ParentResourceName: svc.Name,
ParentResourceUID: string(svc.UID),
Hostname: hostname,
Tags: tags,
ChildResourceLabels: crl,
}
a.mu.Lock()
if a.shouldExpose(svc) {
sts.ClusterTargetIP = svc.Spec.ClusterIP
a.managedIngressProxies.Add(svc.UID)
gaugeIngressProxies.Set(int64(a.managedIngressProxies.Len()))
} else if ip := a.tailnetTargetAnnotation(svc); ip != "" {
sts.TailnetTargetIP = ip
a.managedEgressProxies.Add(svc.UID)
gaugeEgressProxies.Set(int64(a.managedEgressProxies.Len()))
}
a.mu.Unlock()
var hsvc *corev1.Service
if hsvc, err = a.ssr.Provision(ctx, logger, sts); err != nil {
return fmt.Errorf("failed to provision: %w", err)
}
if sts.TailnetTargetIP != "" {
// TODO (irbekrm): cluster.local is the default DNS name, but
// can be changed by users. Make this configurable or figure out
// how to discover the DNS name from within operator
headlessSvcName := hsvc.Name + "." + hsvc.Namespace + ".svc.cluster.local"
if svc.Spec.ExternalName != headlessSvcName || svc.Spec.Type != corev1.ServiceTypeExternalName {
svc.Spec.ExternalName = headlessSvcName
svc.Spec.Selector = nil
svc.Spec.Type = corev1.ServiceTypeExternalName
if err := a.Update(ctx, svc); err != nil {
return fmt.Errorf("failed to update service: %w", err)
}
}
return nil
}
if !a.hasLoadBalancerClass(svc) {
logger.Debugf("service is not a LoadBalancer, so not updating ingress")
return nil
}
_, tsHost, tsIPs, err := a.ssr.DeviceInfo(ctx, crl)
if err != nil {
return fmt.Errorf("failed to get device ID: %w", err)
}
if tsHost == "" {
logger.Debugf("no Tailscale hostname known yet, waiting for proxy pod to finish auth")
// No hostname yet. Wait for the proxy pod to auth.
svc.Status.LoadBalancer.Ingress = nil
if err := a.Status().Update(ctx, svc); err != nil {
return fmt.Errorf("failed to update service status: %w", err)
}
return nil
}
logger.Debugf("setting ingress to %q, %s", tsHost, strings.Join(tsIPs, ", "))
ingress := []corev1.LoadBalancerIngress{
{Hostname: tsHost},
}
clusterIPAddr, err := netip.ParseAddr(svc.Spec.ClusterIP)
if err != nil {
return fmt.Errorf("failed to parse cluster IP: %w", err)
}
for _, ip := range tsIPs {
addr, err := netip.ParseAddr(ip)
if err != nil {
continue
}
if addr.Is4() == clusterIPAddr.Is4() { // only add addresses of the same family
ingress = append(ingress, corev1.LoadBalancerIngress{IP: ip})
}
}
svc.Status.LoadBalancer.Ingress = ingress
if err := a.Status().Update(ctx, svc); err != nil {
return fmt.Errorf("failed to update service status: %w", err)
}
return nil
}
func (a *ServiceReconciler) shouldExpose(svc *corev1.Service) bool {
// Headless services can't be exposed, since there is no ClusterIP to
// forward to.
if svc.Spec.ClusterIP == "" || svc.Spec.ClusterIP == "None" {
return false
}
return a.hasLoadBalancerClass(svc) || a.hasExposeAnnotation(svc)
}
func (a *ServiceReconciler) hasLoadBalancerClass(svc *corev1.Service) bool {
return svc != nil &&
svc.Spec.Type == corev1.ServiceTypeLoadBalancer &&
(svc.Spec.LoadBalancerClass != nil && *svc.Spec.LoadBalancerClass == "tailscale" ||
svc.Spec.LoadBalancerClass == nil && a.isDefaultLoadBalancer)
}
// hasExposeAnnotation reports whether Service has the tailscale.com/expose
// annotation set
func (a *ServiceReconciler) hasExposeAnnotation(svc *corev1.Service) bool {
return svc != nil && svc.Annotations[AnnotationExpose] == "true"
}
// hasTailnetTargetAnnotation returns the value of tailscale.com/tailnet-ip
// annotation or of the deprecated tailscale.com/ts-tailnet-target-ip
// annotation. If neither is set, it returns an empty string. If both are set,
// it returns the value of the new annotation.
func (a *ServiceReconciler) tailnetTargetAnnotation(svc *corev1.Service) string {
if svc == nil {
return ""
}
if ip := svc.Annotations[AnnotationTailnetTargetIP]; ip != "" {
return ip
}
return svc.Annotations[annotationTailnetTargetIPOld]
}