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app.go
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app.go
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// Copyright 2023 SAP SE or an SAP affiliate company. All rights reserved. This file is licensed under the Apache Software License, v. 2 except as noted otherwise in the LICENSE file
//
// 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 app
import (
"context"
"fmt"
"net"
"net/http"
"os"
goruntime "runtime"
"strconv"
"time"
"github.com/go-logr/logr"
"github.com/spf13/cobra"
"github.com/spf13/pflag"
corev1 "k8s.io/api/core/v1"
metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
"k8s.io/apimachinery/pkg/fields"
"k8s.io/apimachinery/pkg/runtime"
"k8s.io/client-go/rest"
clientcmdlatest "k8s.io/client-go/tools/clientcmd/api/latest"
clientcmdv1 "k8s.io/client-go/tools/clientcmd/api/v1"
"k8s.io/component-base/version"
"k8s.io/component-base/version/verflag"
"k8s.io/klog/v2"
"k8s.io/utils/pointer"
"sigs.k8s.io/controller-runtime/pkg/cache"
"sigs.k8s.io/controller-runtime/pkg/client"
controllerconfig "sigs.k8s.io/controller-runtime/pkg/config"
"sigs.k8s.io/controller-runtime/pkg/healthz"
logf "sigs.k8s.io/controller-runtime/pkg/log"
"sigs.k8s.io/controller-runtime/pkg/manager"
metricsserver "sigs.k8s.io/controller-runtime/pkg/metrics/server"
resourcesv1alpha1 "github.com/gardener/gardener/pkg/apis/resources/v1alpha1"
"github.com/gardener/gardener/pkg/client/kubernetes"
"github.com/gardener/gardener/pkg/controllerutils/routes"
"github.com/gardener/gardener/pkg/features"
gardenerhealthz "github.com/gardener/gardener/pkg/healthz"
"github.com/gardener/gardener/pkg/logger"
"github.com/gardener/gardener/pkg/nodeagent/apis/config"
nodeagentv1alpha1 "github.com/gardener/gardener/pkg/nodeagent/apis/config/v1alpha1"
"github.com/gardener/gardener/pkg/nodeagent/controller"
kubernetesutils "github.com/gardener/gardener/pkg/utils/kubernetes"
)
// Name is a const for the name of this component.
const Name = "gardener-node-agent"
// NewCommand creates a new cobra.Command for running gardener-node-agent.
func NewCommand() *cobra.Command {
opts := &options{}
cmd := &cobra.Command{
Use: Name,
Short: "Launch the " + Name,
Args: cobra.NoArgs,
RunE: func(cmd *cobra.Command, args []string) error {
verflag.PrintAndExitIfRequested()
if err := opts.complete(); err != nil {
return err
}
if err := opts.validate(); err != nil {
return err
}
log, err := logger.NewZapLogger(opts.config.LogLevel, opts.config.LogFormat)
if err != nil {
return fmt.Errorf("error instantiating zap logger: %w", err)
}
logf.SetLogger(log)
klog.SetLogger(log)
log.Info("Starting "+Name, "version", version.Get())
cmd.Flags().VisitAll(func(flag *pflag.Flag) {
log.Info(fmt.Sprintf("FLAG: --%s=%s", flag.Name, flag.Value)) //nolint:logcheck
})
// don't output usage on further errors raised during execution
cmd.SilenceUsage = true
// further errors will be logged properly, don't duplicate
cmd.SilenceErrors = true
return run(cmd.Context(), log, opts.config)
},
}
flags := cmd.Flags()
verflag.AddFlags(flags)
opts.addFlags(flags)
return cmd
}
func run(ctx context.Context, log logr.Logger, cfg *config.NodeAgentConfiguration) error {
log.Info("Feature Gates", "featureGates", features.DefaultFeatureGate)
log.Info("Getting rest config")
if kubeconfig := os.Getenv("KUBECONFIG"); kubeconfig != "" {
cfg.ClientConnection.Kubeconfig = kubeconfig
}
if cfg.ClientConnection.Kubeconfig == "" {
return fmt.Errorf("must specify path to a kubeconfig (either via \"KUBECONFIG\" environment variable of via .clientConnection.kubeconfig in component config)")
}
restConfig, err := kubernetes.RESTConfigFromClientConnectionConfiguration(&cfg.ClientConnection, nil, kubernetes.AuthTokenFile)
if err != nil {
return err
}
if restConfig.BearerTokenFile == nodeagentv1alpha1.BootstrapTokenFilePath {
log.Info("Kubeconfig points to the bootstrap token file")
if err := fetchAccessTokenViaBootstrapToken(ctx, log, restConfig, cfg); err != nil {
return fmt.Errorf("failed fetching access token via bootstrap token: %w", err)
}
}
var extraHandlers map[string]http.Handler
if cfg.Debugging != nil && cfg.Debugging.EnableProfiling {
extraHandlers = routes.ProfilingHandlers
if cfg.Debugging.EnableContentionProfiling {
goruntime.SetBlockProfileRate(1)
}
}
log.Info("Fetching node name based on hostname")
nodeName, err := getNodeName(ctx, log, restConfig)
if err != nil {
return err
}
log.Info("Setting up manager")
mgr, err := manager.New(restConfig, manager.Options{
Logger: log,
Scheme: kubernetes.SeedScheme,
GracefulShutdownTimeout: pointer.Duration(5 * time.Second),
HealthProbeBindAddress: net.JoinHostPort(cfg.Server.HealthProbes.BindAddress, strconv.Itoa(cfg.Server.HealthProbes.Port)),
Metrics: metricsserver.Options{
BindAddress: net.JoinHostPort(cfg.Server.Metrics.BindAddress, strconv.Itoa(cfg.Server.Metrics.Port)),
ExtraHandlers: extraHandlers,
},
Cache: cache.Options{
ByObject: map[client.Object]cache.ByObject{
&corev1.Secret{}: {
Namespaces: map[string]cache.Config{metav1.NamespaceSystem: {}},
},
&corev1.Node{}: {
Field: fields.SelectorFromSet(fields.Set{metav1.ObjectNameField: nodeName}),
},
},
},
LeaderElection: false,
Controller: controllerconfig.Controller{
RecoverPanic: pointer.Bool(true),
},
})
if err != nil {
return err
}
log.Info("Setting up health check endpoints")
if err := mgr.AddHealthzCheck("ping", healthz.Ping); err != nil {
return err
}
if err := mgr.AddReadyzCheck("informer-sync", gardenerhealthz.NewCacheSyncHealthz(mgr.GetCache())); err != nil {
return err
}
log.Info("Adding controllers to manager")
if err := controller.AddToManager(mgr, cfg, nodeName); err != nil {
return fmt.Errorf("failed adding controllers to manager: %w", err)
}
log.Info("Starting manager")
return mgr.Start(ctx)
}
func fetchAccessTokenViaBootstrapToken(ctx context.Context, log logr.Logger, restConfig *rest.Config, cfg *config.NodeAgentConfiguration) error {
c, err := client.New(restConfig, client.Options{})
if err != nil {
return fmt.Errorf("unable to create client with bootstrap token: %w", err)
}
secret := &corev1.Secret{ObjectMeta: metav1.ObjectMeta{Name: cfg.Controllers.Token.SecretName, Namespace: metav1.NamespaceSystem}}
log.Info("Fetching access token secret", "secret", client.ObjectKeyFromObject(secret))
if err := c.Get(ctx, client.ObjectKeyFromObject(secret), secret); err != nil {
return fmt.Errorf("failed fetching access token from API server: %w", err)
}
token := secret.Data[resourcesv1alpha1.DataKeyToken]
if len(token) == 0 {
return fmt.Errorf("secret key %q does not exist or empty", resourcesv1alpha1.DataKeyToken)
}
restConfig.BearerTokenFile = nodeagentv1alpha1.TokenFilePath
kubeconfigRaw, err := runtime.Encode(clientcmdlatest.Codec, kubernetesutils.NewKubeconfig(
Name,
clientcmdv1.Cluster{Server: restConfig.Host, CertificateAuthorityData: restConfig.CAData},
clientcmdv1.AuthInfo{TokenFile: nodeagentv1alpha1.TokenFilePath},
))
if err != nil {
return fmt.Errorf("failed encoding kubeconfig: %w", err)
}
log.Info("Writing downloaded access token to disk", "path", nodeagentv1alpha1.TokenFilePath)
if err := os.WriteFile(nodeagentv1alpha1.TokenFilePath, token, 0600); err != nil {
return fmt.Errorf("unable to write access token to %s: %w", nodeagentv1alpha1.TokenFilePath, err)
}
log.Info("Token written to disk")
log.Info("Overwriting kubeconfig on disk to no longer use bootstrap token file", "path", cfg.ClientConnection.Kubeconfig)
if err := os.WriteFile(cfg.ClientConnection.Kubeconfig, kubeconfigRaw, 0600); err != nil {
return fmt.Errorf("unable to write kubeconfig to %s: %w", cfg.ClientConnection.Kubeconfig, err)
}
log.Info("Kubeconfig written to disk")
return nil
}
func getNodeName(ctx context.Context, log logr.Logger, restConfig *rest.Config) (string, error) {
hostname, err := os.Hostname()
if err != nil {
return "", fmt.Errorf("failed fetching hostname: %w", err)
}
cl, err := client.New(restConfig, client.Options{})
if err != nil {
return "", fmt.Errorf("unable to create client: %w", err)
}
nodeList := &metav1.PartialObjectMetadataList{}
nodeList.SetGroupVersionKind(corev1.SchemeGroupVersion.WithKind("NodeList"))
if err := cl.List(ctx, nodeList, client.MatchingLabels{corev1.LabelHostname: hostname}); err != nil {
return "", err
}
switch len(nodeList.Items) {
case 0:
return "", fmt.Errorf("could not find any node with label %s=%s", corev1.LabelHostname, hostname)
case 1:
log.Info("Found node name based on hostname", "hostname", hostname, "nodeName", nodeList.Items[0].Name)
return nodeList.Items[0].Name, nil
default:
return "", fmt.Errorf("found more than one node with label %s=%s", corev1.LabelHostname, hostname)
}
}