prometheus/retrieval/discovery/kubernetes/discovery.go
2016-07-05 14:22:12 +02:00

300 lines
9.7 KiB
Go

// Copyright 2015 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 (
"fmt"
"io/ioutil"
"net"
"net/http"
"os"
"sync"
"time"
"github.com/prometheus/common/log"
"github.com/prometheus/common/model"
"golang.org/x/net/context"
"github.com/prometheus/prometheus/config"
"github.com/prometheus/prometheus/util/httputil"
)
const (
// kubernetesMetaLabelPrefix is the meta prefix used for all meta labels.
// in this discovery.
metaLabelPrefix = model.MetaLabelPrefix + "kubernetes_"
// roleLabel is the name for the label containing a target's role.
roleLabel = metaLabelPrefix + "role"
sourcePodPrefix = "pods"
// podsTargetGroupNAme is the name given to the target group for pods
podsTargetGroupName = "pods"
// podNamespaceLabel is the name for the label containing a target pod's namespace
podNamespaceLabel = metaLabelPrefix + "pod_namespace"
// podNameLabel is the name for the label containing a target pod's name
podNameLabel = metaLabelPrefix + "pod_name"
// podAddressLabel is the name for the label containing a target pod's IP address (the PodIP)
podAddressLabel = metaLabelPrefix + "pod_address"
// podContainerNameLabel is the name for the label containing a target's container name
podContainerNameLabel = metaLabelPrefix + "pod_container_name"
// podContainerPortNameLabel is the name for the label containing the name of the port selected for a target
podContainerPortNameLabel = metaLabelPrefix + "pod_container_port_name"
// PodContainerPortListLabel is the name for the label containing a list of all TCP ports on the target container
podContainerPortListLabel = metaLabelPrefix + "pod_container_port_list"
// PodContainerPortMapPrefix is the prefix used to create the names of labels that associate container port names to port values
// Such labels will be named (podContainerPortMapPrefix)_(PortName) = (ContainerPort)
podContainerPortMapPrefix = metaLabelPrefix + "pod_container_port_map_"
// podReadyLabel is the name for the label containing the 'Ready' status (true/false/unknown) for a target
podReadyLabel = metaLabelPrefix + "pod_ready"
// podLabelPrefix is the prefix for prom label names corresponding to k8s labels for a target pod
podLabelPrefix = metaLabelPrefix + "pod_label_"
// podAnnotationPrefix is the prefix for prom label names corresponding to k8s annotations for a target pod
podAnnotationPrefix = metaLabelPrefix + "pod_annotation_"
sourceServicePrefix = "services"
// serviceNamespaceLabel is the name for the label containing a target's service namespace.
serviceNamespaceLabel = metaLabelPrefix + "service_namespace"
// serviceNameLabel is the name for the label containing a target's service name.
serviceNameLabel = metaLabelPrefix + "service_name"
// serviceLabelPrefix is the prefix for the service labels.
serviceLabelPrefix = metaLabelPrefix + "service_label_"
// serviceAnnotationPrefix is the prefix for the service annotations.
serviceAnnotationPrefix = metaLabelPrefix + "service_annotation_"
// nodesTargetGroupName is the name given to the target group for nodes.
nodesTargetGroupName = "nodes"
// nodeLabelPrefix is the prefix for the node labels.
nodeLabelPrefix = metaLabelPrefix + "node_label_"
// nodeAddressPrefix is the prefix for the node addresses.
nodeAddressPrefix = metaLabelPrefix + "node_address_"
// nodePortLabel is the name of the label for the node port.
nodePortLabel = metaLabelPrefix + "node_port"
// apiServersTargetGroupName is the name given to the target group for API servers.
apiServersTargetGroupName = "apiServers"
serviceAccountToken = "/var/run/secrets/kubernetes.io/serviceaccount/token"
serviceAccountCACert = "/var/run/secrets/kubernetes.io/serviceaccount/ca.crt"
apiVersion = "v1"
apiPrefix = "/api/" + apiVersion
nodesURL = apiPrefix + "/nodes"
podsURL = apiPrefix + "/pods"
servicesURL = apiPrefix + "/services"
endpointsURL = apiPrefix + "/endpoints"
serviceEndpointsURL = apiPrefix + "/namespaces/%s/endpoints/%s"
)
// Discovery implements a TargetProvider for Kubernetes services.
type Discovery struct {
client *http.Client
Conf *config.KubernetesSDConfig
apiServers []config.URL
apiServersMu sync.RWMutex
}
// Initialize sets up the discovery for usage.
func (kd *Discovery) Initialize() error {
client, err := newKubernetesHTTPClient(kd.Conf)
if err != nil {
return err
}
kd.apiServers = kd.Conf.APIServers
kd.client = client
return nil
}
// Run implements the TargetProvider interface.
func (kd *Discovery) Run(ctx context.Context, ch chan<- []*config.TargetGroup) {
log.Debugf("Start Kubernetes service discovery")
defer close(ch)
switch kd.Conf.Role {
case config.KubernetesRolePod, config.KubernetesRoleContainer:
pd := &podDiscovery{
retryInterval: time.Duration(kd.Conf.RetryInterval),
kd: kd,
}
pd.run(ctx, ch)
case config.KubernetesRoleNode:
nd := &nodeDiscovery{
retryInterval: time.Duration(kd.Conf.RetryInterval),
kd: kd,
}
nd.run(ctx, ch)
case config.KubernetesRoleService, config.KubernetesRoleEndpoint:
sd := &serviceDiscovery{
retryInterval: time.Duration(kd.Conf.RetryInterval),
kd: kd,
}
sd.run(ctx, ch)
case config.KubernetesRoleAPIServer:
select {
case ch <- []*config.TargetGroup{kd.updateAPIServersTargetGroup()}:
case <-ctx.Done():
return
}
default:
log.Errorf("unknown Kubernetes discovery kind %q", kd.Conf.Role)
return
}
}
func (kd *Discovery) queryAPIServerPath(path string) (*http.Response, error) {
req, err := http.NewRequest("GET", path, nil)
if err != nil {
return nil, err
}
return kd.queryAPIServerReq(req)
}
func (kd *Discovery) queryAPIServerReq(req *http.Request) (*http.Response, error) {
// Lock in case we need to rotate API servers to request.
kd.apiServersMu.Lock()
defer kd.apiServersMu.Unlock()
var lastErr error
for i := 0; i < len(kd.apiServers); i++ {
cloneReq := *req
cloneReq.URL.Host = kd.apiServers[0].Host
cloneReq.URL.Scheme = kd.apiServers[0].Scheme
res, err := kd.client.Do(&cloneReq)
if err == nil {
return res, nil
}
lastErr = err
kd.rotateAPIServers()
}
return nil, fmt.Errorf("unable to query any API servers: %v", lastErr)
}
func (kd *Discovery) rotateAPIServers() {
if len(kd.apiServers) > 1 {
kd.apiServers = append(kd.apiServers[1:], kd.apiServers[0])
}
}
func (kd *Discovery) updateAPIServersTargetGroup() *config.TargetGroup {
tg := &config.TargetGroup{
Source: apiServersTargetGroupName,
Labels: model.LabelSet{
roleLabel: model.LabelValue("apiserver"),
},
}
for _, apiServer := range kd.apiServers {
apiServerAddress := apiServer.Host
_, _, err := net.SplitHostPort(apiServerAddress)
// If error then no port is specified - use default for scheme.
if err != nil {
switch apiServer.Scheme {
case "http":
apiServerAddress = net.JoinHostPort(apiServerAddress, "80")
case "https":
apiServerAddress = net.JoinHostPort(apiServerAddress, "443")
}
}
t := model.LabelSet{
model.AddressLabel: model.LabelValue(apiServerAddress),
model.SchemeLabel: model.LabelValue(apiServer.Scheme),
}
tg.Targets = append(tg.Targets, t)
}
return tg
}
func newKubernetesHTTPClient(conf *config.KubernetesSDConfig) (*http.Client, error) {
bearerTokenFile := conf.BearerTokenFile
caFile := conf.TLSConfig.CAFile
if conf.InCluster {
if len(bearerTokenFile) == 0 {
bearerTokenFile = serviceAccountToken
}
if len(caFile) == 0 {
// With recent versions, the CA certificate is mounted as a secret
// but we need to handle older versions too. In this case, don't
// set the CAFile & the configuration will have to use InsecureSkipVerify.
if _, err := os.Stat(serviceAccountCACert); err == nil {
caFile = serviceAccountCACert
}
}
}
tlsOpts := httputil.TLSOptions{
InsecureSkipVerify: conf.TLSConfig.InsecureSkipVerify,
CAFile: caFile,
CertFile: conf.TLSConfig.CertFile,
KeyFile: conf.TLSConfig.KeyFile,
}
tlsConfig, err := httputil.NewTLSConfig(tlsOpts)
if err != nil {
return nil, err
}
var rt http.RoundTripper = &http.Transport{
Dial: func(netw, addr string) (c net.Conn, err error) {
c, err = net.DialTimeout(netw, addr, time.Duration(conf.RequestTimeout))
return
},
TLSClientConfig: tlsConfig,
}
// If a bearer token is provided, create a round tripper that will set the
// Authorization header correctly on each request.
bearerToken := conf.BearerToken
if len(bearerToken) == 0 && len(bearerTokenFile) > 0 {
b, err := ioutil.ReadFile(bearerTokenFile)
if err != nil {
return nil, fmt.Errorf("unable to read bearer token file %s: %s", bearerTokenFile, err)
}
bearerToken = string(b)
}
if len(bearerToken) > 0 {
rt = httputil.NewBearerAuthRoundTripper(bearerToken, rt)
}
if conf.BasicAuth != nil {
rt = httputil.NewBasicAuthRoundTripper(conf.BasicAuth.Username, conf.BasicAuth.Password, rt)
}
return &http.Client{
Transport: rt,
}, nil
}
// Until loops until stop channel is closed, running f every period.
// f may not be invoked if stop channel is already closed.
func until(f func(), period time.Duration, stopCh <-chan struct{}) {
select {
case <-stopCh:
return
default:
f()
}
for {
select {
case <-stopCh:
return
case <-time.After(period):
f()
}
}
}