Add initial support for daemonsets (#217)

Signed-off-by: galal-hussein <[email protected]>

Author: galal-hussein

k3k-kubelet/config.go

@@ -11,7 +11,7 @@ import (
 type config struct {
 	ClusterName       string `yaml:"clusterName,omitempty"`
 	ClusterNamespace  string `yaml:"clusterNamespace,omitempty"`
-	NodeName          string `yaml:"nodeName,omitempty"`
+	ServiceName       string `yaml:"serviceName,omitempty"`
 	Token             string `yaml:"token,omitempty"`
 	AgentHostname     string `yaml:"agentHostname,omitempty"`
 	HostConfigPath    string `yaml:"hostConfigPath,omitempty"`
@@ -46,8 +46,8 @@ func (c *config) unmarshalYAML(data []byte) error {
 	if c.AgentHostname == "" {
 		c.AgentHostname = conf.AgentHostname
 	}
-	if c.NodeName == "" {
-		c.NodeName = conf.NodeName
+	if c.ServiceName == "" {
+		c.ServiceName = conf.ServiceName
 	}
 	if c.Token == "" {
 		c.Token = conf.Token

k3k-kubelet/controller/webhook/pod.go

@@ -33,6 +33,7 @@ type webhookHandler struct {
 	client           ctrlruntimeclient.Client
 	scheme           *runtime.Scheme
 	nodeName         string
+	serviceName      string
 	clusterName      string
 	clusterNamespace string
 	logger           *log.Logger
@@ -41,11 +42,12 @@ type webhookHandler struct {
 // AddPodMutatorWebhook will add a mutator webhook to the virtual cluster to
 // modify the nodeName of the created pods with the name of the virtual kubelet node name
 // as well as remove any status fields of the downward apis env fields
-func AddPodMutatorWebhook(ctx context.Context, mgr manager.Manager, hostClient ctrlruntimeclient.Client, clusterName, clusterNamespace, nodeName string, logger *log.Logger) error {
+func AddPodMutatorWebhook(ctx context.Context, mgr manager.Manager, hostClient ctrlruntimeclient.Client, clusterName, clusterNamespace, nodeName, serviceName string, logger *log.Logger) error {
 	handler := webhookHandler{
 		client:           mgr.GetClient(),
 		scheme:           mgr.GetScheme(),
 		logger:           logger,
+		serviceName:      serviceName,
 		clusterName:      clusterName,
 		clusterNamespace: clusterNamespace,
 		nodeName:         nodeName,
@@ -107,7 +109,7 @@ func (w *webhookHandler) configuration(ctx context.Context, hostClient ctrlrunti
 	if !ok {
 		return nil, errors.New("webhook CABundle does not exist in secret")
 	}
-	webhookURL := "https://" + w.nodeName + ":" + webhookPort + webhookPath
+	webhookURL := "https://" + w.serviceName + ":" + webhookPort + webhookPath
 	return &admissionregistrationv1.MutatingWebhookConfiguration{
 		TypeMeta: metav1.TypeMeta{
 			APIVersion: "admissionregistration.k8s.io/v1",

k3k-kubelet/kubelet.go

@@ -127,7 +127,7 @@ func newKubelet(ctx context.Context, c *config, logger *k3klog.Logger) (*kubelet
 		return nil, errors.New("unable to create controller-runtime mgr for virtual cluster: " + err.Error())
 	}
 	logger.Info("adding pod mutator webhook")
-	if err := k3kwebhook.AddPodMutatorWebhook(ctx, virtualMgr, hostClient, c.ClusterName, c.ClusterNamespace, c.NodeName, logger); err != nil {
+	if err := k3kwebhook.AddPodMutatorWebhook(ctx, virtualMgr, hostClient, c.ClusterName, c.ClusterNamespace, c.AgentHostname, c.ServiceName, logger); err != nil {
 		return nil, errors.New("unable to add pod mutator webhook for virtual cluster: " + err.Error())
 	}
 
@@ -141,7 +141,7 @@ func newKubelet(ctx context.Context, c *config, logger *k3klog.Logger) (*kubelet
 		return nil, errors.New("failed to add pvc syncer controller: " + err.Error())
 	}
 
-	clusterIP, err := clusterIP(ctx, c.AgentHostname, c.ClusterNamespace, hostClient)
+	clusterIP, err := clusterIP(ctx, c.ServiceName, c.ClusterNamespace, hostClient)
 	if err != nil {
 		return nil, errors.New("failed to extract the clusterIP for the server service: " + err.Error())
 	}
@@ -161,7 +161,7 @@ func newKubelet(ctx context.Context, c *config, logger *k3klog.Logger) (*kubelet
 	return &kubelet{
 		virtualCluster: virtualCluster,
 
-		name:       c.NodeName,
+		name:       c.AgentHostname,
 		hostConfig: hostConfig,
 		hostClient: hostClient,
 		virtConfig: virtConfig,

k3k-kubelet/main.go

@@ -61,6 +61,12 @@ func main() {
 			EnvVars:     []string{"SERVER_PORT"},
 			Value:       "10250",
 		},
+		&cli.StringFlag{
+			Name:        "service-name",
+			Usage:       "The service name deployed by the k3k controller",
+			Destination: &cfg.ServiceName,
+			EnvVars:     []string{"SERVICE_NAME"},
+		},
 		&cli.StringFlag{
 			Name:        "agent-hostname",
 			Usage:       "Agent Hostname used for TLS SAN for the kubelet server",

pkg/controller/cluster/agent/shared.go

@@ -44,7 +44,7 @@ func NewSharedAgent(cluster *v1alpha1.Cluster, serviceIP, image, imagePullPolicy
 }
 
 func (s *SharedAgent) Config() ctrlruntimeclient.Object {
-	config := sharedAgentData(s.cluster, s.token, s.Name(), s.serviceIP)
+	config := sharedAgentData(s.cluster, s.Name(), s.token, s.serviceIP)
 
 	return &v1.Secret{
 		TypeMeta: metav1.TypeMeta{
@@ -61,19 +61,18 @@ func (s *SharedAgent) Config() ctrlruntimeclient.Object {
 	}
 }
 
-func sharedAgentData(cluster *v1alpha1.Cluster, token, nodeName, ip string) string {
+func sharedAgentData(cluster *v1alpha1.Cluster, serviceName, token, ip string) string {
 	version := cluster.Spec.Version
 	if cluster.Spec.Version == "" {
 		version = cluster.Status.HostVersion
 	}
 	return fmt.Sprintf(`clusterName: %s
 clusterNamespace: %s
-nodeName: %s
-agentHostname: %s
 serverIP: %s
+serviceName: %s
 token: %s
 version: %s`,
-		cluster.Name, cluster.Namespace, nodeName, nodeName, ip, token, version)
+		cluster.Name, cluster.Namespace, ip, serviceName, token, version)
 }
 
 func (s *SharedAgent) Resources() ([]ctrlruntimeclient.Object, error) {
@@ -178,6 +177,17 @@ func (s *SharedAgent) podSpec() v1.PodSpec {
 					"--config",
 					sharedKubeletConfigPath,
 				},
+				Env: []v1.EnvVar{
+					{
+						Name: "AGENT_HOSTNAME",
+						ValueFrom: &v1.EnvVarSource{
+							FieldRef: &v1.ObjectFieldSelector{
+								APIVersion: "v1",
+								FieldPath:  "spec.nodeName",
+							},
+						},
+					},
+				},
 				VolumeMounts: []v1.VolumeMount{
 					{
 						Name:      "config",