main.go

/*
 * (c) Copyright IBM Corp. 2021
 * (c) Copyright Instana Inc. 2021
 */

package main

import (
	"context"
	"flag"
	"fmt"
	"os"
	"runtime"
	"strconv"

	appsv1 "k8s.io/api/apps/v1"
	rbacv1 "k8s.io/api/rbac/v1"
	"k8s.io/apimachinery/pkg/api/errors"
	"k8s.io/apimachinery/pkg/fields"
	"k8s.io/apimachinery/pkg/labels"
	k8sruntime "k8s.io/apimachinery/pkg/runtime"
	"k8s.io/apimachinery/pkg/types"
	utilruntime "k8s.io/apimachinery/pkg/util/runtime"
	clientgoscheme "k8s.io/client-go/kubernetes/scheme"
	_ "k8s.io/client-go/plugin/pkg/client/auth"
	ctrl "sigs.k8s.io/controller-runtime"
	"sigs.k8s.io/controller-runtime/pkg/client"
	k8sClient "sigs.k8s.io/controller-runtime/pkg/client"
	"sigs.k8s.io/controller-runtime/pkg/healthz"
	logf "sigs.k8s.io/controller-runtime/pkg/log"
	"sigs.k8s.io/controller-runtime/pkg/log/zap"
	metricsserver "sigs.k8s.io/controller-runtime/pkg/metrics/server"

	agentoperatorv1 "github.com/instana/instana-agent-operator/api/v1"
	"github.com/instana/instana-agent-operator/controllers"
	instanaclient "github.com/instana/instana-agent-operator/pkg/k8s/client"
	"github.com/instana/instana-agent-operator/version"
	// +kubebuilder:scaffold:imports
)

var (
	scheme = k8sruntime.NewScheme()
	log    = logf.Log.WithName("main")
)

func init() {
	utilruntime.Must(clientgoscheme.AddToScheme(scheme))

	utilruntime.Must(agentoperatorv1.AddToScheme(scheme))
	utilruntime.Must(appsv1.AddToScheme(scheme))
	// +kubebuilder:scaffold:scheme
}

func main() {
	var metricsAddr string
	var probeAddr string
	var enableLeaderElection bool
	flag.StringVar(&metricsAddr, "metrics-bind-address", ":8080", "The address the metric endpoint binds to.")
	flag.StringVar(&probeAddr, "health-probe-bind-address", ":8081", "The address the probe endpoint binds to.")
	// By default disable leader-election and assume single instance gets installed. Via parameters (--leader-elect) it will be
	// enabled from the Operator Deployment spec.
	flag.BoolVar(
		&enableLeaderElection, "leader-elect", false,
		"Enable leader election for controller manager. "+
			"Enabling this will ensure there is only one active controller manager.",
	)

	// When running in debug-mode, include some more logging etc
	debugMode, _ := strconv.ParseBool(os.Getenv("DEBUG_MODE"))

	opts := zap.Options{
		Development: debugMode,
	}
	opts.BindFlags(flag.CommandLine)
	flag.Parse()

	// Set the Logger to be used also by the controller-runtime
	logf.SetLogger(zap.New(zap.UseFlagOptions(&opts)).WithName("instana"))

	printVersion()
	cfg := ctrl.GetConfigOrDie()

	mgr, err := ctrl.NewManager(
		cfg, ctrl.Options{
			Metrics: metricsserver.Options{
				BindAddress: metricsAddr,
			},
			Scheme:                 scheme,
			HealthProbeBindAddress: probeAddr,
			LeaderElection:         enableLeaderElection,
			LeaderElectionID:       "819a9291.instana.io",
		},
	)
	if err != nil {
		log.Error(err, "Unable to start manager")
		os.Exit(1)
	}

	if err := mgr.AddHealthzCheck("healthz", healthz.Ping); err != nil {
		log.Error(err, "Unable to set up health check")
		os.Exit(1)
	}
	if err := mgr.AddReadyzCheck("readyz", healthz.Ping); err != nil {
		log.Error(err, "Unable to set up ready check")
		os.Exit(1)
	}
	// Add our own Agent Controller to the manager
	if err := controllers.Add(mgr); err != nil {
		log.Error(err, "Failure setting up Instana Agent Controller")
		os.Exit(1)
	}

	// controller-manager only runs controllers/runnables after getting the lock
	// we do the cleanup beforehand so our new deployment gets the lock
	log.Info("Deleting the controller-manager deployment and RBAC if it's present")
	//we need a new client because we have to delete old resources before starting the new manager
	if client, err := k8sClient.New(cfg, k8sClient.Options{
		Scheme: scheme,
	}); err != nil {
		log.Error(err, "Failed to create a new k8s client")
	} else {
		cleanupOldOperator(client)
	}

	log.Info("Starting manager")
	if err := mgr.Start(ctrl.SetupSignalHandler()); err != nil {
		log.Error(err, "Problem running manager")
		os.Exit(1)
	}
}

func cleanupOldOperator(k8sClient k8sClient.Client) {
	const labelKey string = "app.kubernetes.io/name"
	const InstanaOperatorOldDeploymentName string = "controller-manager"
	const InstanaOperatorOldClusterRoleName string = "manager-role"
	const InstanaOperatorOldClusterRoleBindingName string = "manager-rolebinding"

	log.Info("Delete the old deployment if present")
	deploymentsList := &appsv1.DeploymentList{}
	// check that resources match with the old name
	fieldSelector := fields.OneTermEqualSelector("metadata.name", InstanaOperatorOldDeploymentName)
	// check that resources have label "app.kubernetes.io/name: instana-agent-operator"
	labelSelector := labels.SelectorFromSet(labels.Set{labelKey: instanaclient.FieldOwnerName})

	deploymentOptions := &client.ListOptions{
		FieldSelector: fieldSelector,
		LabelSelector: labelSelector,
		// checking all namespaces
	}

	if err := k8sClient.List(context.Background(), deploymentsList, deploymentOptions); err != nil {
		log.Info(fmt.Sprintf("Failed to get list the deployment with the label %s:%s and name %s", labelKey, instanaclient.FieldOwnerName, InstanaOperatorOldDeploymentName))
	} else {
		// there should be only one deployment but we iterate just in case
		log.Info(fmt.Sprintf("Found %v deployments that match the criteria", len(deploymentsList.Items)))
		for _, deployment := range deploymentsList.Items {
			ns := deployment.GetNamespace()
			log.Info(fmt.Sprintf("Deleting the old operator deployment %s in namespace %s", InstanaOperatorOldDeploymentName, ns))
			if err := k8sClient.Delete(context.Background(), &deployment); err != nil {
				log.Info(fmt.Sprintf("Failed to delete the old operator deployment %s", InstanaOperatorOldDeploymentName))
			} else {
				log.Info(fmt.Sprintf("Successfully deleted the deployment %s", InstanaOperatorOldDeploymentName))
			}
		}
	}

	log.Info("Delete old RBAC resources if present")
	oldRole := &rbacv1.ClusterRole{}
	roleKey := types.NamespacedName{
		Name: InstanaOperatorOldClusterRoleName,
	}
	if err := k8sClient.Get(context.Background(), roleKey, oldRole); err != nil {
		if errors.IsNotFound(err) {
			log.Info("Old operator clusterrole is not present in the cluster")
		} else {
			log.Error(err, "Failed to get the old operator clusterrole "+InstanaOperatorOldClusterRoleName)
		}
	} else {
		// check if it has an API group "instana.io"
		hasInstanaApiGroup := false
		for _, rule := range oldRole.Rules {
			for _, apiGroup := range rule.APIGroups {
				if apiGroup == "instana.io" {
					hasInstanaApiGroup = true
					break
				}
			}
			if hasInstanaApiGroup {
				break
			}
		}
		if !hasInstanaApiGroup {
			log.Info(fmt.Sprintf("ClusterRole with name %s found, but it's not coming from instana; skipping the deletion", InstanaOperatorOldClusterRoleName))
		} else {
			log.Info(fmt.Sprintf("Deleting the old operator clusterrole %s", InstanaOperatorOldClusterRoleName))
			if err := k8sClient.Delete(context.Background(), oldRole); err != nil {
				log.Info(fmt.Sprintf("Failed to delete the old operator clusterrole %s", InstanaOperatorOldClusterRoleName))
			} else {
				log.Info(fmt.Sprintf("Successfully deleted the clusterrole %s", InstanaOperatorOldClusterRoleName))
			}
		}
	}

	oldRoleBinding := &rbacv1.ClusterRoleBinding{}
	bindingKey := types.NamespacedName{
		Name: InstanaOperatorOldClusterRoleBindingName,
	}
	if err := k8sClient.Get(context.Background(), bindingKey, oldRoleBinding); err != nil {
		if errors.IsNotFound(err) {
			log.Info("Old operator clusterrolebinding is not present in the cluster")
		} else {
			log.Error(err, "Failed to get the old operator clusterrolebinding "+InstanaOperatorOldClusterRoleBindingName)
		}
	} else {
		hasInstanaAgentOperatorSA := false
		for _, subject := range oldRoleBinding.Subjects {
			if subject.Kind == "ServiceAccount" && subject.Name == instanaclient.FieldOwnerName {
				hasInstanaAgentOperatorSA = true
				break
			}
		}
		if !hasInstanaAgentOperatorSA {
			log.Info(fmt.Sprintf("ClusterRoleBinding with name %s found, but the SA doesn't match; skipping the deletion", InstanaOperatorOldClusterRoleBindingName))
		} else {
			log.Info(fmt.Sprintf("Deleting the old operator clusterrolebinding %s", InstanaOperatorOldClusterRoleBindingName))
			if err := k8sClient.Delete(context.Background(), oldRoleBinding); err != nil {
				log.Info("Failed to delete the old operator clusterrolebinding " + InstanaOperatorOldClusterRoleBindingName)
			} else {
				log.Info(fmt.Sprintf("Successfully deleted the clusterrolebinding %s", InstanaOperatorOldClusterRoleBindingName))
			}
		}
	}
}

func printVersion() {
	log.Info(fmt.Sprintf("Operator Version: %s", version.Version))
	log.Info(fmt.Sprintf("Operator Git Commit SHA: %s", version.GitCommit))
	log.Info(fmt.Sprintf("Go Version: %s", runtime.Version()))
	log.Info(fmt.Sprintf("Go OS/Arch: %s/%s", runtime.GOOS, runtime.GOARCH))
}