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prometheus/discovery/kubernetes/kubernetes.go

385 lines
12 KiB

// Copyright 2016 The Prometheus Authors
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package kubernetes
import (
"context"
"fmt"
"io/ioutil"
"sync"
"time"
"github.com/go-kit/kit/log"
"github.com/go-kit/kit/log/level"
"github.com/prometheus/client_golang/prometheus"
config_util "github.com/prometheus/common/config"
"github.com/prometheus/common/model"
"github.com/prometheus/prometheus/discovery/targetgroup"
metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
"k8s.io/apimachinery/pkg/runtime"
"k8s.io/apimachinery/pkg/watch"
"k8s.io/client-go/kubernetes"
"k8s.io/client-go/pkg/api"
apiv1 "k8s.io/client-go/pkg/api/v1"
extensionsv1beta1 "k8s.io/client-go/pkg/apis/extensions/v1beta1"
"k8s.io/client-go/rest"
"k8s.io/client-go/tools/cache"
)
const (
// kubernetesMetaLabelPrefix is the meta prefix used for all meta labels.
// in this discovery.
metaLabelPrefix = model.MetaLabelPrefix + "kubernetes_"
namespaceLabel = metaLabelPrefix + "namespace"
)
var (
eventCount = prometheus.NewCounterVec(
prometheus.CounterOpts{
Name: "prometheus_sd_kubernetes_events_total",
Help: "The number of Kubernetes events handled.",
},
[]string{"role", "event"},
)
// DefaultSDConfig is the default Kubernetes SD configuration
DefaultSDConfig = SDConfig{}
)
// Role is role of the service in Kubernetes.
type Role string
// The valid options for Role.
const (
RoleNode Role = "node"
RolePod Role = "pod"
RoleService Role = "service"
RoleEndpoint Role = "endpoints"
RoleIngress Role = "ingress"
)
// UnmarshalYAML implements the yaml.Unmarshaler interface.
func (c *Role) UnmarshalYAML(unmarshal func(interface{}) error) error {
if err := unmarshal((*string)(c)); err != nil {
return err
}
switch *c {
case RoleNode, RolePod, RoleService, RoleEndpoint, RoleIngress:
return nil
default:
return fmt.Errorf("Unknown Kubernetes SD role %q", *c)
}
}
// SDConfig is the configuration for Kubernetes service discovery.
type SDConfig struct {
APIServer config_util.URL `yaml:"api_server"`
Role Role `yaml:"role"`
BasicAuth *config_util.BasicAuth `yaml:"basic_auth,omitempty"`
BearerToken config_util.Secret `yaml:"bearer_token,omitempty"`
BearerTokenFile string `yaml:"bearer_token_file,omitempty"`
TLSConfig config_util.TLSConfig `yaml:"tls_config,omitempty"`
NamespaceDiscovery NamespaceDiscovery `yaml:"namespaces"`
}
// UnmarshalYAML implements the yaml.Unmarshaler interface.
func (c *SDConfig) UnmarshalYAML(unmarshal func(interface{}) error) error {
*c = SDConfig{}
type plain SDConfig
err := unmarshal((*plain)(c))
if err != nil {
return err
}
if c.Role == "" {
return fmt.Errorf("role missing (one of: pod, service, endpoints, node)")
}
if len(c.BearerToken) > 0 && len(c.BearerTokenFile) > 0 {
return fmt.Errorf("at most one of bearer_token & bearer_token_file must be configured")
}
if c.BasicAuth != nil && (len(c.BearerToken) > 0 || len(c.BearerTokenFile) > 0) {
return fmt.Errorf("at most one of basic_auth, bearer_token & bearer_token_file must be configured")
}
if c.APIServer.URL == nil &&
(c.BasicAuth != nil || c.BearerToken != "" || c.BearerTokenFile != "" ||
c.TLSConfig.CAFile != "" || c.TLSConfig.CertFile != "" || c.TLSConfig.KeyFile != "") {
return fmt.Errorf("to use custom authentication please provide the 'api_server' URL explicitly")
}
return nil
}
// NamespaceDiscovery is the configuration for discovering
// Kubernetes namespaces.
type NamespaceDiscovery struct {
Names []string `yaml:"names"`
}
// UnmarshalYAML implements the yaml.Unmarshaler interface.
func (c *NamespaceDiscovery) UnmarshalYAML(unmarshal func(interface{}) error) error {
*c = NamespaceDiscovery{}
type plain NamespaceDiscovery
return unmarshal((*plain)(c))
}
func init() {
prometheus.MustRegister(eventCount)
// Initialize metric vectors.
for _, role := range []string{"endpoints", "node", "pod", "service"} {
for _, evt := range []string{"add", "delete", "update"} {
eventCount.WithLabelValues(role, evt)
}
}
}
// This is only for internal use.
type discoverer interface {
Run(ctx context.Context, up chan<- []*targetgroup.Group)
}
// Discovery implements the discoverer interface for discovering
// targets from Kubernetes.
type Discovery struct {
sync.RWMutex
client kubernetes.Interface
role Role
logger log.Logger
namespaceDiscovery *NamespaceDiscovery
discoverers []discoverer
}
func (d *Discovery) getNamespaces() []string {
namespaces := d.namespaceDiscovery.Names
if len(namespaces) == 0 {
namespaces = []string{api.NamespaceAll}
}
return namespaces
}
// New creates a new Kubernetes discovery for the given role.
func New(l log.Logger, conf *SDConfig) (*Discovery, error) {
if l == nil {
l = log.NewNopLogger()
}
var (
kcfg *rest.Config
err error
)
if conf.APIServer.URL == nil {
// Use the Kubernetes provided pod service account
// as described in https://kubernetes.io/docs/admin/service-accounts-admin/
kcfg, err = rest.InClusterConfig()
if err != nil {
return nil, err
}
// Because the handling of configuration parameters changes
// we should inform the user when their currently configured values
// will be ignored due to precedence of InClusterConfig
level.Info(l).Log("msg", "Using pod service account via in-cluster config")
if conf.TLSConfig.CAFile != "" {
level.Warn(l).Log("msg", "Configured TLS CA file is ignored when using pod service account")
}
if conf.TLSConfig.CertFile != "" || conf.TLSConfig.KeyFile != "" {
level.Warn(l).Log("msg", "Configured TLS client certificate is ignored when using pod service account")
}
if conf.BearerToken != "" {
level.Warn(l).Log("msg", "Configured auth token is ignored when using pod service account")
}
if conf.BasicAuth != nil {
level.Warn(l).Log("msg", "Configured basic authentication credentials are ignored when using pod service account")
}
} else {
kcfg = &rest.Config{
Host: conf.APIServer.String(),
TLSClientConfig: rest.TLSClientConfig{
CAFile: conf.TLSConfig.CAFile,
CertFile: conf.TLSConfig.CertFile,
KeyFile: conf.TLSConfig.KeyFile,
Insecure: conf.TLSConfig.InsecureSkipVerify,
},
}
token := string(conf.BearerToken)
if conf.BearerTokenFile != "" {
bf, err := ioutil.ReadFile(conf.BearerTokenFile)
if err != nil {
return nil, err
}
token = string(bf)
}
kcfg.BearerToken = token
if conf.BasicAuth != nil {
kcfg.Username = conf.BasicAuth.Username
kcfg.Password = string(conf.BasicAuth.Password)
}
}
kcfg.UserAgent = "prometheus/discovery"
c, err := kubernetes.NewForConfig(kcfg)
if err != nil {
return nil, err
}
return &Discovery{
client: c,
logger: l,
role: conf.Role,
namespaceDiscovery: &conf.NamespaceDiscovery,
discoverers: make([]discoverer, 0),
}, nil
}
const resyncPeriod = 10 * time.Minute
// Run implements the discoverer interface.
func (d *Discovery) Run(ctx context.Context, ch chan<- []*targetgroup.Group) {
d.Lock()
namespaces := d.getNamespaces()
switch d.role {
case RoleEndpoint:
for _, namespace := range namespaces {
elw := &cache.ListWatch{
ListFunc: func(options metav1.ListOptions) (runtime.Object, error) {
return d.client.CoreV1().Endpoints(namespace).List(options)
},
WatchFunc: func(options metav1.ListOptions) (watch.Interface, error) {
return d.client.CoreV1().Endpoints(namespace).Watch(options)
},
}
slw := &cache.ListWatch{
ListFunc: func(options metav1.ListOptions) (runtime.Object, error) {
return d.client.CoreV1().Services(namespace).List(options)
},
WatchFunc: func(options metav1.ListOptions) (watch.Interface, error) {
return d.client.CoreV1().Services(namespace).Watch(options)
},
}
plw := &cache.ListWatch{
ListFunc: func(options metav1.ListOptions) (runtime.Object, error) {
return d.client.CoreV1().Pods(namespace).List(options)
},
WatchFunc: func(options metav1.ListOptions) (watch.Interface, error) {
return d.client.CoreV1().Pods(namespace).Watch(options)
},
}
eps := NewEndpoints(
log.With(d.logger, "role", "endpoint"),
cache.NewSharedInformer(slw, &apiv1.Service{}, resyncPeriod),
cache.NewSharedInformer(elw, &apiv1.Endpoints{}, resyncPeriod),
cache.NewSharedInformer(plw, &apiv1.Pod{}, resyncPeriod),
)
d.discoverers = append(d.discoverers, eps)
go eps.endpointsInf.Run(ctx.Done())
go eps.serviceInf.Run(ctx.Done())
go eps.podInf.Run(ctx.Done())
}
case RolePod:
for _, namespace := range namespaces {
plw := &cache.ListWatch{
ListFunc: func(options metav1.ListOptions) (runtime.Object, error) {
return d.client.CoreV1().Pods(namespace).List(options)
},
WatchFunc: func(options metav1.ListOptions) (watch.Interface, error) {
return d.client.CoreV1().Pods(namespace).Watch(options)
},
}
pod := NewPod(
log.With(d.logger, "role", "pod"),
cache.NewSharedInformer(plw, &apiv1.Pod{}, resyncPeriod),
)
d.discoverers = append(d.discoverers, pod)
go pod.informer.Run(ctx.Done())
}
case RoleService:
for _, namespace := range namespaces {
slw := &cache.ListWatch{
ListFunc: func(options metav1.ListOptions) (runtime.Object, error) {
return d.client.CoreV1().Services(namespace).List(options)
},
WatchFunc: func(options metav1.ListOptions) (watch.Interface, error) {
return d.client.CoreV1().Services(namespace).Watch(options)
},
}
svc := NewService(
log.With(d.logger, "role", "service"),
cache.NewSharedInformer(slw, &apiv1.Service{}, resyncPeriod),
)
d.discoverers = append(d.discoverers, svc)
go svc.informer.Run(ctx.Done())
}
case RoleIngress:
for _, namespace := range namespaces {
ilw := &cache.ListWatch{
ListFunc: func(options metav1.ListOptions) (runtime.Object, error) {
return d.client.ExtensionsV1beta1().Ingresses(namespace).List(options)
},
WatchFunc: func(options metav1.ListOptions) (watch.Interface, error) {
return d.client.ExtensionsV1beta1().Ingresses(namespace).Watch(options)
},
}
ingress := NewIngress(
log.With(d.logger, "role", "ingress"),
cache.NewSharedInformer(ilw, &extensionsv1beta1.Ingress{}, resyncPeriod),
)
d.discoverers = append(d.discoverers, ingress)
go ingress.informer.Run(ctx.Done())
}
case RoleNode:
nlw := &cache.ListWatch{
ListFunc: func(options metav1.ListOptions) (runtime.Object, error) {
return d.client.CoreV1().Nodes().List(options)
},
WatchFunc: func(options metav1.ListOptions) (watch.Interface, error) {
return d.client.CoreV1().Nodes().Watch(options)
},
}
node := NewNode(
log.With(d.logger, "role", "node"),
cache.NewSharedInformer(nlw, &apiv1.Node{}, resyncPeriod),
)
d.discoverers = append(d.discoverers, node)
go node.informer.Run(ctx.Done())
default:
level.Error(d.logger).Log("msg", "unknown Kubernetes discovery kind", "role", d.role)
}
var wg sync.WaitGroup
for _, dd := range d.discoverers {
wg.Add(1)
go func(d discoverer) {
defer wg.Done()
d.Run(ctx, ch)
}(dd)
}
d.Unlock()
<-ctx.Done()
}
func lv(s string) model.LabelValue {
return model.LabelValue(s)
}
func send(ctx context.Context, l log.Logger, role Role, ch chan<- []*targetgroup.Group, tg *targetgroup.Group) {
if tg == nil {
return
}
level.Debug(l).Log("msg", "kubernetes discovery update", "role", string(role), "tg", fmt.Sprintf("%#v", tg))
select {
case <-ctx.Done():
case ch <- []*targetgroup.Group{tg}:
}
}