k3s/pkg/cloudprovider/servicelb.go

721 lines
21 KiB
Go

package cloudprovider
import (
"context"
"fmt"
"sort"
"strconv"
"strings"
"time"
"github.com/k3s-io/k3s/pkg/util"
"github.com/k3s-io/k3s/pkg/version"
"github.com/rancher/wrangler/v3/pkg/condition"
coreclient "github.com/rancher/wrangler/v3/pkg/generated/controllers/core/v1"
discoveryclient "github.com/rancher/wrangler/v3/pkg/generated/controllers/discovery/v1"
"github.com/rancher/wrangler/v3/pkg/merr"
"github.com/rancher/wrangler/v3/pkg/objectset"
"github.com/sirupsen/logrus"
apps "k8s.io/api/apps/v1"
core "k8s.io/api/core/v1"
discovery "k8s.io/api/discovery/v1"
apierrors "k8s.io/apimachinery/pkg/api/errors"
meta "k8s.io/apimachinery/pkg/apis/meta/v1"
"k8s.io/apimachinery/pkg/labels"
"k8s.io/apimachinery/pkg/util/intstr"
"k8s.io/apimachinery/pkg/util/wait"
utilfeature "k8s.io/apiserver/pkg/util/feature"
"k8s.io/client-go/util/retry"
ccmapp "k8s.io/cloud-provider/app"
servicehelper "k8s.io/cloud-provider/service/helpers"
"k8s.io/kubernetes/pkg/features"
utilsnet "k8s.io/utils/net"
utilsptr "k8s.io/utils/ptr"
)
var (
finalizerName = "svccontroller." + version.Program + ".cattle.io/daemonset"
svcNameLabel = "svccontroller." + version.Program + ".cattle.io/svcname"
svcNamespaceLabel = "svccontroller." + version.Program + ".cattle.io/svcnamespace"
daemonsetNodeLabel = "svccontroller." + version.Program + ".cattle.io/enablelb"
daemonsetNodePoolLabel = "svccontroller." + version.Program + ".cattle.io/lbpool"
nodeSelectorLabel = "svccontroller." + version.Program + ".cattle.io/nodeselector"
controllerName = ccmapp.DefaultInitFuncConstructors["service"].InitContext.ClientName
)
const (
Ready = condition.Cond("Ready")
DefaultLBNS = meta.NamespaceSystem
)
var (
DefaultLBImage = "rancher/klipper-lb:v0.4.7"
)
func (k *k3s) Register(ctx context.Context,
nodes coreclient.NodeController,
pods coreclient.PodController,
endpointslices discoveryclient.EndpointSliceController,
) error {
nodes.OnChange(ctx, controllerName, k.onChangeNode)
pods.OnChange(ctx, controllerName, k.onChangePod)
endpointslices.OnChange(ctx, controllerName, k.onChangeEndpointSlice)
if err := k.ensureServiceLBNamespace(ctx); err != nil {
return err
}
if err := k.ensureServiceLBServiceAccount(ctx); err != nil {
return err
}
go wait.Until(k.runWorker, time.Second, ctx.Done())
return k.removeServiceFinalizers(ctx)
}
// ensureServiceLBNamespace ensures that the configured namespace exists.
func (k *k3s) ensureServiceLBNamespace(ctx context.Context) error {
ns := k.client.CoreV1().Namespaces()
if _, err := ns.Get(ctx, k.LBNamespace, meta.GetOptions{}); err == nil || !apierrors.IsNotFound(err) {
return err
}
_, err := ns.Create(ctx, &core.Namespace{
ObjectMeta: meta.ObjectMeta{
Name: k.LBNamespace,
},
}, meta.CreateOptions{})
if apierrors.IsAlreadyExists(err) {
return nil
}
return err
}
// ensureServiceLBServiceAccount ensures that the ServiceAccount used by pods exists.
func (k *k3s) ensureServiceLBServiceAccount(ctx context.Context) error {
sa := k.client.CoreV1().ServiceAccounts(k.LBNamespace)
if _, err := sa.Get(ctx, "svclb", meta.GetOptions{}); err == nil || !apierrors.IsNotFound(err) {
return err
}
_, err := sa.Create(ctx, &core.ServiceAccount{
ObjectMeta: meta.ObjectMeta{
Name: "svclb",
Namespace: k.LBNamespace,
},
}, meta.CreateOptions{})
if apierrors.IsAlreadyExists(err) {
return nil
}
return err
}
// onChangePod handles changes to Pods.
// If the pod has labels that tie it to a service, and the pod has an IP assigned,
// enqueue an update to the service's status.
func (k *k3s) onChangePod(key string, pod *core.Pod) (*core.Pod, error) {
if pod == nil {
return nil, nil
}
serviceName := pod.Labels[svcNameLabel]
if serviceName == "" {
return pod, nil
}
serviceNamespace := pod.Labels[svcNamespaceLabel]
if serviceNamespace == "" {
return pod, nil
}
if pod.Status.PodIP == "" {
return pod, nil
}
k.workqueue.Add(serviceNamespace + "/" + serviceName)
return pod, nil
}
// onChangeNode handles changes to Nodes. We need to handle this as we may need to kick the DaemonSet
// to add or remove pods from nodes if labels have changed.
func (k *k3s) onChangeNode(key string, node *core.Node) (*core.Node, error) {
if node == nil {
return nil, nil
}
if _, ok := node.Labels[daemonsetNodeLabel]; !ok {
return node, nil
}
if err := k.updateDaemonSets(); err != nil {
return node, err
}
return node, nil
}
// onChangeEndpointSlice handles changes to EndpointSlices. This is used to ensure that LoadBalancer
// addresses only list Nodes with ready Pods, when their ExternalTrafficPolicy is set to Local.
func (k *k3s) onChangeEndpointSlice(key string, eps *discovery.EndpointSlice) (*discovery.EndpointSlice, error) {
if eps == nil {
return nil, nil
}
serviceName, ok := eps.Labels[discovery.LabelServiceName]
if !ok {
return eps, nil
}
k.workqueue.Add(eps.Namespace + "/" + serviceName)
return eps, nil
}
// runWorker dequeues Service changes from the work queue
// We run a lightweight work queue to handle service updates. We don't need the full overhead
// of a wrangler service controller and shared informer cache, but we do want to run changes
// through a keyed queue to reduce thrashing when pods are updated. Much of this is cribbed from
// https://github.com/rancher/lasso/blob/release/v2.5/pkg/controller/controller.go#L173-L215
func (k *k3s) runWorker() {
for k.processNextWorkItem() {
}
}
// processNextWorkItem does work for a single item in the queue,
// returning a boolean that indicates if the queue should continue
// to be serviced.
func (k *k3s) processNextWorkItem() bool {
obj, shutdown := k.workqueue.Get()
if shutdown {
return false
}
if err := k.processSingleItem(obj); err != nil && !apierrors.IsConflict(err) {
logrus.Errorf("%s: %v", controllerName, err)
}
return true
}
// processSingleItem processes a single item from the work queue,
// requeueing it if the handler fails.
func (k *k3s) processSingleItem(obj interface{}) error {
var (
key string
ok bool
)
defer k.workqueue.Done(obj)
if key, ok = obj.(string); !ok {
logrus.Errorf("expected string in workqueue but got %#v", obj)
k.workqueue.Forget(obj)
return nil
}
keyParts := strings.SplitN(key, "/", 2)
if err := k.updateStatus(keyParts[0], keyParts[1]); err != nil {
k.workqueue.AddRateLimited(key)
return fmt.Errorf("error updating LoadBalancer Status for %s: %v, requeueing", key, err)
}
k.workqueue.Forget(obj)
return nil
}
// updateServiceStatus updates the load balancer status for the matching service, if it exists and is a
// LoadBalancer service. The patchStatus function handles checking to see if status needs updating.
func (k *k3s) updateStatus(namespace, name string) error {
svc, err := k.client.CoreV1().Services(namespace).Get(context.TODO(), name, meta.GetOptions{})
if err != nil {
if apierrors.IsNotFound(err) {
return nil
}
return err
}
if svc.Spec.Type != core.ServiceTypeLoadBalancer {
return nil
}
previousStatus := svc.Status.LoadBalancer.DeepCopy()
newStatus, err := k.getStatus(svc)
if err != nil {
return err
}
return k.patchStatus(svc, previousStatus, newStatus)
}
// getDaemonSet returns the DaemonSet that should exist for the Service.
func (k *k3s) getDaemonSet(svc *core.Service) (*apps.DaemonSet, error) {
return k.daemonsetCache.Get(k.LBNamespace, generateName(svc))
}
// getStatus returns a LoadBalancerStatus listing ingress IPs for all ready pods
// matching the selected service.
func (k *k3s) getStatus(svc *core.Service) (*core.LoadBalancerStatus, error) {
var readyNodes map[string]bool
if servicehelper.RequestsOnlyLocalTraffic(svc) {
readyNodes = map[string]bool{}
eps, err := k.endpointsCache.List(svc.Namespace, labels.SelectorFromSet(labels.Set{
discovery.LabelServiceName: svc.Name,
}))
if err != nil {
return nil, err
}
for _, ep := range eps {
for _, endpoint := range ep.Endpoints {
isPod := endpoint.TargetRef != nil && endpoint.TargetRef.Kind == "Pod"
isReady := endpoint.Conditions.Ready != nil && *endpoint.Conditions.Ready
if isPod && isReady && endpoint.NodeName != nil {
readyNodes[*endpoint.NodeName] = true
}
}
}
}
pods, err := k.podCache.List(k.LBNamespace, labels.SelectorFromSet(labels.Set{
svcNameLabel: svc.Name,
svcNamespaceLabel: svc.Namespace,
}))
if err != nil {
return nil, err
}
expectedIPs, err := k.podIPs(pods, svc, readyNodes)
if err != nil {
return nil, err
}
loadbalancer := &core.LoadBalancerStatus{}
for _, ip := range expectedIPs {
loadbalancer.Ingress = append(loadbalancer.Ingress, core.LoadBalancerIngress{
IP: ip,
})
}
return loadbalancer, nil
}
// patchStatus patches the service status. If the status has not changed, this function is a no-op.
func (k *k3s) patchStatus(svc *core.Service, previousStatus, newStatus *core.LoadBalancerStatus) error {
if servicehelper.LoadBalancerStatusEqual(previousStatus, newStatus) {
return nil
}
updated := svc.DeepCopy()
updated.Status.LoadBalancer = *newStatus
_, err := servicehelper.PatchService(k.client.CoreV1(), svc, updated)
if err == nil {
if len(newStatus.Ingress) == 0 {
k.recorder.Event(svc, core.EventTypeWarning, "UnAvailableLoadBalancer", "There are no available nodes for LoadBalancer")
} else {
k.recorder.Eventf(svc, core.EventTypeNormal, "UpdatedLoadBalancer", "Updated LoadBalancer with new IPs: %v -> %v", ingressToString(previousStatus.Ingress), ingressToString(newStatus.Ingress))
}
}
return err
}
// podIPs returns a list of IPs for Nodes hosting ServiceLB Pods.
// If at least one node has External IPs available, only external IPs are returned.
// If no nodes have External IPs set, the Internal IPs of all nodes running pods are returned.
func (k *k3s) podIPs(pods []*core.Pod, svc *core.Service, readyNodes map[string]bool) ([]string, error) {
// Go doesn't have sets so we stuff things into a map of bools and then get lists of keys
// to determine the unique set of IPs in use by pods.
extIPs := map[string]bool{}
intIPs := map[string]bool{}
for _, pod := range pods {
if pod.Spec.NodeName == "" || pod.Status.PodIP == "" {
continue
}
if !Ready.IsTrue(pod) {
continue
}
if readyNodes != nil && !readyNodes[pod.Spec.NodeName] {
continue
}
node, err := k.nodeCache.Get(pod.Spec.NodeName)
if apierrors.IsNotFound(err) {
continue
} else if err != nil {
return nil, err
}
for _, addr := range node.Status.Addresses {
if addr.Type == core.NodeExternalIP {
extIPs[addr.Address] = true
} else if addr.Type == core.NodeInternalIP {
intIPs[addr.Address] = true
}
}
}
keys := func(addrs map[string]bool) (ips []string) {
for k := range addrs {
ips = append(ips, k)
}
return ips
}
var ips []string
if len(extIPs) > 0 {
ips = keys(extIPs)
} else {
ips = keys(intIPs)
}
ips, err := filterByIPFamily(ips, svc)
if err != nil {
return nil, err
}
if len(ips) > 0 && k.Rootless {
return []string{"127.0.0.1"}, nil
}
return ips, nil
}
// filterByIPFamily filters node IPs based on dual-stack parameters of the service
func filterByIPFamily(ips []string, svc *core.Service) ([]string, error) {
var ipv4Addresses []string
var ipv6Addresses []string
var allAddresses []string
for _, ip := range ips {
if utilsnet.IsIPv4String(ip) {
ipv4Addresses = append(ipv4Addresses, ip)
}
if utilsnet.IsIPv6String(ip) {
ipv6Addresses = append(ipv6Addresses, ip)
}
}
sort.Strings(ipv4Addresses)
sort.Strings(ipv6Addresses)
for _, ipFamily := range svc.Spec.IPFamilies {
switch ipFamily {
case core.IPv4Protocol:
allAddresses = append(allAddresses, ipv4Addresses...)
case core.IPv6Protocol:
allAddresses = append(allAddresses, ipv6Addresses...)
}
}
return allAddresses, nil
}
// deployDaemonSet ensures that there is a DaemonSet for the service.
func (k *k3s) deployDaemonSet(ctx context.Context, svc *core.Service) error {
ds, err := k.newDaemonSet(svc)
if err != nil {
return err
}
defer k.recorder.Eventf(svc, core.EventTypeNormal, "AppliedDaemonSet", "Applied LoadBalancer DaemonSet %s/%s", ds.Namespace, ds.Name)
return k.processor.WithContext(ctx).WithOwner(svc).Apply(objectset.NewObjectSet(ds))
}
// deleteDaemonSet ensures that there are no DaemonSets for the given service.
func (k *k3s) deleteDaemonSet(ctx context.Context, svc *core.Service) error {
name := generateName(svc)
if err := k.client.AppsV1().DaemonSets(k.LBNamespace).Delete(ctx, name, meta.DeleteOptions{}); err != nil {
if apierrors.IsNotFound(err) {
return nil
}
return err
}
defer k.recorder.Eventf(svc, core.EventTypeNormal, "DeletedDaemonSet", "Deleted LoadBalancer DaemonSet %s/%s", k.LBNamespace, name)
return nil
}
// newDaemonSet creates a DaemonSet to ensure that ServiceLB pods are run on
// each eligible node.
func (k *k3s) newDaemonSet(svc *core.Service) (*apps.DaemonSet, error) {
name := generateName(svc)
oneInt := intstr.FromInt(1)
localTraffic := servicehelper.RequestsOnlyLocalTraffic(svc)
sourceRangesSet, err := servicehelper.GetLoadBalancerSourceRanges(svc)
if err != nil {
return nil, err
}
sourceRanges := strings.Join(sourceRangesSet.StringSlice(), ",")
var sysctls []core.Sysctl
for _, ipFamily := range svc.Spec.IPFamilies {
switch ipFamily {
case core.IPv4Protocol:
sysctls = append(sysctls, core.Sysctl{Name: "net.ipv4.ip_forward", Value: "1"})
case core.IPv6Protocol:
sysctls = append(sysctls, core.Sysctl{Name: "net.ipv6.conf.all.forwarding", Value: "1"})
// The upstream default load-balancer source range only includes IPv4, even if the service is IPv6-only or dual-stack.
// If using the default range, and IPv6 is enabled, also allow IPv6.
if sourceRanges == "0.0.0.0/0" {
sourceRanges += ",::/0"
}
}
}
ds := &apps.DaemonSet{
ObjectMeta: meta.ObjectMeta{
Name: name,
Namespace: k.LBNamespace,
Labels: labels.Set{
nodeSelectorLabel: "false",
svcNameLabel: svc.Name,
svcNamespaceLabel: svc.Namespace,
},
},
TypeMeta: meta.TypeMeta{
Kind: "DaemonSet",
APIVersion: "apps/v1",
},
Spec: apps.DaemonSetSpec{
Selector: &meta.LabelSelector{
MatchLabels: labels.Set{
"app": name,
},
},
Template: core.PodTemplateSpec{
ObjectMeta: meta.ObjectMeta{
Labels: labels.Set{
"app": name,
svcNameLabel: svc.Name,
svcNamespaceLabel: svc.Namespace,
},
},
Spec: core.PodSpec{
ServiceAccountName: "svclb",
AutomountServiceAccountToken: utilsptr.To(false),
SecurityContext: &core.PodSecurityContext{
Sysctls: sysctls,
},
Tolerations: []core.Toleration{
{
Key: util.MasterRoleLabelKey,
Operator: "Exists",
Effect: "NoSchedule",
},
{
Key: util.ControlPlaneRoleLabelKey,
Operator: "Exists",
Effect: "NoSchedule",
},
{
Key: "CriticalAddonsOnly",
Operator: "Exists",
},
},
},
},
UpdateStrategy: apps.DaemonSetUpdateStrategy{
Type: apps.RollingUpdateDaemonSetStrategyType,
RollingUpdate: &apps.RollingUpdateDaemonSet{
MaxUnavailable: &oneInt,
},
},
},
}
for _, port := range svc.Spec.Ports {
portName := fmt.Sprintf("lb-%s-%d", strings.ToLower(string(port.Protocol)), port.Port)
container := core.Container{
Name: portName,
Image: k.LBImage,
ImagePullPolicy: core.PullIfNotPresent,
Ports: []core.ContainerPort{
{
Name: portName,
ContainerPort: port.Port,
HostPort: port.Port,
Protocol: port.Protocol,
},
},
Env: []core.EnvVar{
{
Name: "SRC_PORT",
Value: strconv.Itoa(int(port.Port)),
},
{
Name: "SRC_RANGES",
Value: sourceRanges,
},
{
Name: "DEST_PROTO",
Value: string(port.Protocol),
},
},
SecurityContext: &core.SecurityContext{
Capabilities: &core.Capabilities{
Add: []core.Capability{
"NET_ADMIN",
},
},
},
}
if localTraffic {
container.Env = append(container.Env,
core.EnvVar{
Name: "DEST_PORT",
Value: strconv.Itoa(int(port.NodePort)),
},
core.EnvVar{
Name: "DEST_IPS",
ValueFrom: &core.EnvVarSource{
FieldRef: &core.ObjectFieldSelector{
FieldPath: getHostIPsFieldPath(),
},
},
},
)
} else {
container.Env = append(container.Env,
core.EnvVar{
Name: "DEST_PORT",
Value: strconv.Itoa(int(port.Port)),
},
core.EnvVar{
Name: "DEST_IPS",
Value: strings.Join(svc.Spec.ClusterIPs, ","),
},
)
}
ds.Spec.Template.Spec.Containers = append(ds.Spec.Template.Spec.Containers, container)
}
// Add node selector only if label "svccontroller.k3s.cattle.io/enablelb" exists on the nodes
enableNodeSelector, err := k.nodeHasDaemonSetLabel()
if err != nil {
return nil, err
}
if enableNodeSelector {
ds.Spec.Template.Spec.NodeSelector = map[string]string{
daemonsetNodeLabel: "true",
}
// Add node selector for "svccontroller.k3s.cattle.io/lbpool=<pool>" if service has lbpool label
if svc.Labels[daemonsetNodePoolLabel] != "" {
ds.Spec.Template.Spec.NodeSelector[daemonsetNodePoolLabel] = svc.Labels[daemonsetNodePoolLabel]
}
ds.Labels[nodeSelectorLabel] = "true"
}
return ds, nil
}
// updateDaemonSets ensures that our DaemonSets have a NodeSelector present if one is enabled,
// and do not have one if it is not. Nodes are checked for this label when the DaemonSet is generated,
// but node labels may change between Service updates and the NodeSelector needs to be updated appropriately.
func (k *k3s) updateDaemonSets() error {
enableNodeSelector, err := k.nodeHasDaemonSetLabel()
if err != nil {
return err
}
nodeSelector := labels.SelectorFromSet(labels.Set{nodeSelectorLabel: fmt.Sprintf("%t", !enableNodeSelector)})
daemonsets, err := k.daemonsetCache.List(k.LBNamespace, nodeSelector)
if err != nil {
return err
}
for _, ds := range daemonsets {
ds.Labels[nodeSelectorLabel] = fmt.Sprintf("%t", enableNodeSelector)
ds.Spec.Template.Spec.NodeSelector = map[string]string{}
if enableNodeSelector {
ds.Spec.Template.Spec.NodeSelector[daemonsetNodeLabel] = "true"
}
if _, err := k.client.AppsV1().DaemonSets(ds.Namespace).Update(context.TODO(), ds, meta.UpdateOptions{}); err != nil {
return err
}
}
return nil
}
// nodeHasDaemonSetLabel returns true if any node is labeled for inclusion or exclusion
// from use by ServiceLB. If any node is labeled, only nodes with a label value of "true"
// will be used.
func (k *k3s) nodeHasDaemonSetLabel() (bool, error) {
selector, err := labels.Parse(daemonsetNodeLabel)
if err != nil {
return false, err
}
nodesWithLabel, err := k.nodeCache.List(selector)
return len(nodesWithLabel) > 0, err
}
// deleteAllDaemonsets deletes all daemonsets created by this controller
func (k *k3s) deleteAllDaemonsets(ctx context.Context) error {
return k.client.AppsV1().DaemonSets(k.LBNamespace).DeleteCollection(ctx, meta.DeleteOptions{}, meta.ListOptions{LabelSelector: nodeSelectorLabel})
}
// removeServiceFinalizers ensures that there are no finalizers left on any services.
// Previous implementations of the servicelb controller manually added finalizers to services it managed;
// these need to be removed in order to release ownership to the cloud provider implementation.
func (k *k3s) removeServiceFinalizers(ctx context.Context) error {
services, err := k.client.CoreV1().Services(meta.NamespaceAll).List(ctx, meta.ListOptions{})
if err != nil {
return err
}
var errs merr.Errors
for _, svc := range services.Items {
if err := retry.RetryOnConflict(retry.DefaultRetry, func() error {
s, err := k.removeFinalizer(ctx, &svc)
svc = *s
return err
}); err != nil {
errs = append(errs, err)
}
}
if len(errs) > 0 {
return errs
}
return nil
}
// removeFinalizer ensures that there is not a finalizer for this controller on the Service
func (k *k3s) removeFinalizer(ctx context.Context, svc *core.Service) (*core.Service, error) {
var found bool
for k, v := range svc.Finalizers {
if v != finalizerName {
continue
}
found = true
svc.Finalizers = append(svc.Finalizers[:k], svc.Finalizers[k+1:]...)
}
if found {
return k.client.CoreV1().Services(svc.Namespace).Update(ctx, svc, meta.UpdateOptions{})
}
return svc, nil
}
// generateName generates a distinct name for the DaemonSet based on the service name and UID
func generateName(svc *core.Service) string {
return fmt.Sprintf("svclb-%s-%s", svc.Name, svc.UID[:8])
}
// ingressToString converts a list of LoadBalancerIngress entries to strings
func ingressToString(ingresses []core.LoadBalancerIngress) []string {
parts := make([]string, len(ingresses))
for i, ingress := range ingresses {
if ingress.IP != "" {
parts[i] = ingress.IP
} else {
parts[i] = ingress.Hostname
}
}
return parts
}
func getHostIPsFieldPath() string {
if utilfeature.DefaultFeatureGate.Enabled(features.PodHostIPs) {
return "status.hostIPs"
}
return "status.hostIP"
}