prometheus/retrieval/discovery/kubernetes/discovery.go
Fabian Reinartz 7221228843 discovery/kubernetes: select between discovery role
This adds `role` field to the Kubernetes SD config, which indicates
which type of Kubernetes SD should be run.
This no longer allows discovering pods and nodes with the same SD
configuration for example.
2016-07-05 14:22:12 +02:00

302 lines
9.8 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
runDone chan struct{}
}
// 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
kd.runDone = make(chan struct{})
return nil
}
// Run implements the TargetProvider interface.
func (kd *Discovery) Run(ctx context.Context, ch chan<- []*config.TargetGroup) {
log.Debugf("Kubernetes Discovery.Run beginning")
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()
}
}
}