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kubernetes: add multicluster support (#7266)
* kubernetes: add multicluster support Add multicluster support via Multi-Cluster Services API (MCS-API) via a new option `multiclusterZones` in the kubernetes plugin. When some multicluster zones are passed to the kubernetes plugin, it will start watching the ServiceImport objects and its associated EndpointSlices. Signed-off-by: Arthur Outhenin-Chalandre <arthur@cri.epita.fr> * kubernetes: implement xfr support for multicluster zones Signed-off-by: Arthur Outhenin-Chalandre <arthur@cri.epita.fr> --------- Signed-off-by: Arthur Outhenin-Chalandre <arthur@cri.epita.fr>
This commit is contained in:
Arthur Outhenin-Chalandre
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GitHub
GitHub
parent
76b199f829
commit
5c71bd0b87
@@ -26,6 +26,7 @@ import (
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"k8s.io/client-go/rest"
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"k8s.io/client-go/tools/clientcmd"
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clientcmdapi "k8s.io/client-go/tools/clientcmd/api"
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mcsClientset "sigs.k8s.io/mcs-api/pkg/client/clientset/versioned/typed/apis/v1alpha1"
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)
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// Kubernetes implements a plugin that connects to a Kubernetes cluster.
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@@ -237,6 +238,14 @@ func (k *Kubernetes) InitKubeCache(ctx context.Context) (onStart func() error, o
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return nil, nil, fmt.Errorf("failed to create kubernetes notification controller: %q", err)
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}
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var mcsClient mcsClientset.MulticlusterV1alpha1Interface
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if len(k.opts.multiclusterZones) > 0 {
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mcsClient, err = mcsClientset.NewForConfig(config)
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if err != nil {
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return nil, nil, fmt.Errorf("failed to create kubernetes multicluster notification controller: %q", err)
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}
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}
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if k.opts.labelSelector != nil {
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var selector labels.Selector
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selector, err = meta.LabelSelectorAsSelector(k.opts.labelSelector)
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@@ -260,7 +269,7 @@ func (k *Kubernetes) InitKubeCache(ctx context.Context) (onStart func() error, o
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k.opts.zones = k.Zones
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k.opts.endpointNameMode = k.endpointNameMode
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k.APIConn = newdnsController(ctx, kubeClient, k.opts)
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k.APIConn = newdnsController(ctx, kubeClient, mcsClient, k.opts)
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onStart = func() error {
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go func() {
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@@ -299,7 +308,8 @@ func (k *Kubernetes) InitKubeCache(ctx context.Context) (onStart func() error, o
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// Records looks up services in kubernetes.
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func (k *Kubernetes) Records(ctx context.Context, state request.Request, exact bool) ([]msg.Service, error) {
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r, e := parseRequest(state.Name(), state.Zone)
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multicluster := k.isMultiClusterZone(state.Zone)
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r, e := parseRequest(state.Name(), state.Zone, multicluster)
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if e != nil {
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return nil, e
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}
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@@ -320,7 +330,13 @@ func (k *Kubernetes) Records(ctx context.Context, state request.Request, exact b
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return pods, err
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}
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services, err := k.findServices(r, state.Zone)
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var services []msg.Service
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var err error
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if !multicluster {
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services, err = k.findServices(r, state.Zone)
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} else {
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services, err = k.findMultiClusterServices(r, state.Zone)
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}
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return services, err
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}
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@@ -518,12 +534,127 @@ func (k *Kubernetes) findServices(r recordRequest, zone string) (services []msg.
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return services, err
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}
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// findMultiClusterServices returns the multicluster services matching r from the cache.
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func (k *Kubernetes) findMultiClusterServices(r recordRequest, zone string) (services []msg.Service, err error) {
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if !k.namespaceExposed(r.namespace) {
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return nil, errNoItems
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}
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// handle empty service name
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if r.service == "" {
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if k.namespaceExposed(r.namespace) {
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// NODATA
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return nil, nil
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}
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// NXDOMAIN
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return nil, errNoItems
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}
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err = errNoItems
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var (
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endpointsListFunc func() []*object.MultiClusterEndpoints
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endpointsList []*object.MultiClusterEndpoints
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serviceList []*object.ServiceImport
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)
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idx := object.ServiceImportKey(r.service, r.namespace)
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serviceList = k.APIConn.SvcImportIndex(idx)
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endpointsListFunc = func() []*object.MultiClusterEndpoints { return k.APIConn.McEpIndex(idx) }
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zonePath := msg.Path(zone, coredns)
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for _, svc := range serviceList {
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if !match(r.namespace, svc.Namespace) || !match(r.service, svc.Name) {
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continue
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}
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// If "ignore empty_service" option is set and no endpoints exist, return NXDOMAIN unless
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// it's a headless or externalName service (covered below).
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if k.opts.ignoreEmptyService && !svc.Headless() { // serve NXDOMAIN if no endpoint is able to answer
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podsCount := 0
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for _, ep := range endpointsListFunc() {
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for _, eps := range ep.Subsets {
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podsCount += len(eps.Addresses)
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}
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}
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if podsCount == 0 {
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continue
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}
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}
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// Endpoint query or headless service
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if svc.Headless() || r.endpoint != "" {
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if endpointsList == nil {
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endpointsList = endpointsListFunc()
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}
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for _, ep := range endpointsList {
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if object.MultiClusterEndpointsKey(svc.Name, svc.Namespace) != ep.Index {
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continue
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}
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for _, eps := range ep.Subsets {
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for _, addr := range eps.Addresses {
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// See comments in parse.go parseRequest about the endpoint handling.
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if r.endpoint != "" {
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if !match(r.cluster, ep.ClusterId) || !match(r.endpoint, endpointHostname(addr, k.endpointNameMode)) {
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continue
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}
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}
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for _, p := range eps.Ports {
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if !(matchPortAndProtocol(r.port, p.Name, r.protocol, p.Protocol)) {
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continue
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}
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s := msg.Service{Host: addr.IP, Port: int(p.Port), TTL: k.ttl}
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s.Key = strings.Join([]string{zonePath, Svc, svc.Namespace, svc.Name, ep.ClusterId, endpointHostname(addr, k.endpointNameMode)}, "/")
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err = nil
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services = append(services, s)
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}
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}
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}
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}
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continue
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}
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// ClusterIP service
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for _, p := range svc.Ports {
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if !(matchPortAndProtocol(r.port, p.Name, r.protocol, string(p.Protocol))) {
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continue
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}
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err = nil
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for _, ip := range svc.ClusterIPs {
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s := msg.Service{Host: ip, Port: int(p.Port), TTL: k.ttl}
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s.Key = strings.Join([]string{zonePath, Svc, svc.Namespace, svc.Name}, "/")
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services = append(services, s)
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}
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}
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}
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return services, err
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}
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// Serial return the SOA serial.
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func (k *Kubernetes) Serial(state request.Request) uint32 { return uint32(k.APIConn.Modified(false)) }
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func (k *Kubernetes) Serial(state request.Request) uint32 {
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if !k.isMultiClusterZone(state.Zone) {
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return uint32(k.APIConn.Modified(ModifiedInternal))
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} else {
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return uint32(k.APIConn.Modified(ModifiedMultiCluster))
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}
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}
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// MinTTL returns the minimal TTL.
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func (k *Kubernetes) MinTTL(state request.Request) uint32 { return k.ttl }
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func (k *Kubernetes) isMultiClusterZone(zone string) bool {
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z := plugin.Zones(k.opts.multiclusterZones).Matches(zone)
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return z != ""
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}
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// match checks if a and b are equal.
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func match(a, b string) bool {
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return strings.EqualFold(a, b)
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