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register.go
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register.go
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package register
import (
"context"
"fmt"
"net/http"
"os"
"time"
"github.com/sirupsen/logrus"
"github.com/rancher/fleet/internal/config"
"github.com/rancher/fleet/internal/registration"
fleet "github.com/rancher/fleet/pkg/apis/fleet.cattle.io/v1alpha1"
"github.com/rancher/fleet/pkg/durations"
fleetcontrollers "github.com/rancher/fleet/pkg/generated/controllers/fleet.cattle.io"
"github.com/rancher/wrangler/v2/pkg/generated/controllers/core"
corecontrollers "github.com/rancher/wrangler/v2/pkg/generated/controllers/core/v1"
"github.com/rancher/wrangler/v2/pkg/randomtoken"
"github.com/rancher/wrangler/v2/pkg/ratelimit"
corev1 "k8s.io/api/core/v1"
apierrors "k8s.io/apimachinery/pkg/api/errors"
metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
"k8s.io/client-go/kubernetes"
"k8s.io/client-go/rest"
"k8s.io/client-go/tools/clientcmd"
clientcmdapi "k8s.io/client-go/tools/clientcmd/api"
"sigs.k8s.io/yaml"
)
const (
CredName = "fleet-agent" // same as AgentConfigName
Kubeconfig = "kubeconfig"
Token = "token"
Values = "values"
DeploymentNamespace = "deploymentNamespace"
ClusterNamespace = "clusterNamespace"
ClusterName = "clusterName"
)
type AgentInfo struct {
ClusterNamespace string
ClusterName string
ClientConfig clientcmd.ClientConfig
}
func Register(ctx context.Context, namespace, clusterID string, config *rest.Config) (*AgentInfo, error) {
for {
cfg, err := tryRegister(ctx, namespace, clusterID, config)
if err == nil {
return cfg, nil
}
logrus.Errorf("Failed to register agent: %v", err)
select {
case <-ctx.Done():
return nil, ctx.Err()
case <-time.After(durations.AgentRegistrationRetry):
}
}
}
// tryRegister makes sure the secret cattle-fleet-system/fleet-agent is
// populated and the contained kubeconfig is working
func tryRegister(ctx context.Context, namespace, clusterID string, cfg *rest.Config) (*AgentInfo, error) {
cfg = rest.CopyConfig(cfg)
// disable the rate limiter
cfg.RateLimiter = ratelimit.None
k8s, err := core.NewFactoryFromConfig(cfg)
if err != nil {
return nil, err
}
secret, err := k8s.Core().V1().Secret().Get(namespace, CredName, metav1.GetOptions{})
if apierrors.IsNotFound(err) {
logrus.Warn("Cannot find fleet-agent secret, running registration")
// fallback to local cattle-fleet-system/fleet-agent-bootstrap
secret, err = runRegistration(ctx, k8s.Core().V1(), namespace, clusterID)
if err != nil {
return nil, fmt.Errorf("registration failed: %w", err)
}
} else if err != nil {
return nil, err
} else if err := testClientConfig(secret.Data[Kubeconfig]); err != nil {
// skip testClientConfig check if previous error, or IsNotFound fallback succeeded
logrus.Errorf("Current credential failed, failing back to reregistering: %v", err)
secret, err = runRegistration(ctx, k8s.Core().V1(), namespace, clusterID)
if err != nil {
return nil, fmt.Errorf("re-registration failed: %w", err)
}
}
clientConfig, err := clientcmd.NewClientConfigFromBytes(secret.Data[Kubeconfig])
if err != nil {
return nil, err
}
// delete the fleet-agent-bootstrap cred
_ = k8s.Core().V1().Secret().Delete(namespace, config.AgentBootstrapConfigName, nil)
return &AgentInfo{
ClusterNamespace: string(secret.Data[ClusterNamespace]),
ClusterName: string(secret.Data[ClusterName]),
ClientConfig: clientConfig,
}, nil
}
// coreInterface is a subset of corecontrollers.Interface
type coreInterface interface {
ConfigMap() corecontrollers.ConfigMapController
Namespace() corecontrollers.NamespaceController
Secret() corecontrollers.SecretController
}
// runRegistration reads the cattle-fleet-system/fleet-agent-bootstrap secret and
// waits for the registration secret to appear on the management cluster to
// create a new fleet-agent secret.
// It uses the token provided in fleet-agent-bootstrap to build a
// kubeconfig and create a ClusterRegistration on the management cluster.
// Then it waits up to 30 minutes for the registration secret
// "c-clientID-clientRandom" to appear in the systemRegistrationNamespace on
// the management cluster.
// Finally uses the client from the config (service account: fleet-agent), to
// update the "fleet-agent" secret with a new kubeconfig from the registration
// secret. The new kubeconfig can then be used to query bundledeployments.
func runRegistration(ctx context.Context, k8s coreInterface, namespace, clusterID string) (*corev1.Secret, error) {
secret, err := k8s.Secret().Get(namespace, config.AgentBootstrapConfigName, metav1.GetOptions{})
if err != nil {
return nil, fmt.Errorf("looking up secret %s/%s: %w", namespace, config.AgentBootstrapConfigName, err)
}
clientConfig := createClientConfigFromSecret(secret)
ns, _, err := clientConfig.Namespace()
if err != nil {
return nil, err
}
kc, err := clientConfig.ClientConfig()
if err != nil {
return nil, err
}
cfg, err := config.Lookup(ctx, secret.Namespace, config.AgentConfigName, k8s.ConfigMap())
if err != nil {
return nil, fmt.Errorf("failed to look up client config %s/%s: %w", secret.Namespace, config.AgentConfigName, err)
}
fleetK8s, err := kubernetes.NewForConfig(kc)
if err != nil {
return nil, err
}
fc, err := fleetcontrollers.NewFactoryFromConfig(kc)
if err != nil {
return nil, err
}
token, err := randomtoken.Generate()
if err != nil {
return nil, err
}
if cfg.ClientID != "" {
clusterID = cfg.ClientID
} else if clusterID == "" {
kubeSystem, err := k8s.Namespace().Get("kube-system", metav1.GetOptions{})
if err != nil {
return nil, fmt.Errorf("cannot retrieve our kubeSystem.UID: %w", err)
}
clusterID = string(kubeSystem.UID)
}
// add the name of the pod that created the registration for debugging
if cfg.Labels == nil {
cfg.Labels = map[string]string{}
}
cfg.Labels["fleet.cattle.io/created-by-agent-pod"] = os.Getenv("HOSTNAME")
logrus.Infof("Creating clusterregistration with id '%s' for new token", clusterID)
request, err := fc.Fleet().V1alpha1().ClusterRegistration().Create(&fleet.ClusterRegistration{
ObjectMeta: metav1.ObjectMeta{
GenerateName: "request-",
Namespace: ns,
},
Spec: fleet.ClusterRegistrationSpec{
ClientID: clusterID,
ClientRandom: token,
ClusterLabels: cfg.Labels,
},
})
if err != nil {
return nil, fmt.Errorf("cannot create clusterregistration on management cluster for cluster id '%s': %w", clusterID, err)
}
secretName := registration.SecretName(request.Spec.ClientID, request.Spec.ClientRandom)
secretNamespace := string(values(secret.Data)["systemRegistrationNamespace"])
timeout := time.After(durations.CreateClusterSecretTimeout)
for {
select {
case <-timeout:
return nil, fmt.Errorf("timeout waiting for registration secret '%s/%s' on management cluster", secretNamespace, secretName)
case <-ctx.Done():
return nil, ctx.Err()
case <-time.After(durations.ClusterSecretRetry):
}
newSecret, err := fleetK8s.CoreV1().Secrets(secretNamespace).Get(ctx, secretName, metav1.GetOptions{})
if err != nil {
logrus.Infof("Waiting for secret '%s/%s' on management cluster for request '%s/%s': %v", secretNamespace, secretName, request.Namespace, request.Name, err)
continue
}
newToken := newSecret.Data[Token]
clusterNamespace := newSecret.Data[ClusterNamespace]
clusterName := newSecret.Data[ClusterName]
deploymentNamespace := newSecret.Data[DeploymentNamespace]
newKubeconfig, err := updateClientConfig(clientConfig, string(newToken), string(deploymentNamespace))
if err != nil {
return nil, err
}
if err := testClientConfig(newKubeconfig); err != nil {
return nil, fmt.Errorf("new client config cannot list bundledeployments on management cluster: %w", err)
}
// fleet-agent secret
agentSecret := &corev1.Secret{
ObjectMeta: metav1.ObjectMeta{
Name: CredName,
Namespace: secret.Namespace,
},
Data: map[string][]byte{
Kubeconfig: newKubeconfig,
DeploymentNamespace: deploymentNamespace,
ClusterNamespace: clusterNamespace,
ClusterName: clusterName,
},
}
secret, err := k8s.Secret().Create(agentSecret)
if apierrors.IsAlreadyExists(err) {
if err = k8s.Secret().Delete(agentSecret.Namespace, agentSecret.Name, &metav1.DeleteOptions{}); err != nil {
return nil, err
}
secret, err = k8s.Secret().Create(agentSecret)
}
if err != nil {
err = fmt.Errorf("failed to create 'fleet-agent' secret: %w", err)
}
return secret, err
}
}
func values(data map[string][]byte) map[string][]byte {
values := data[Values]
if len(values) == 0 {
return data
}
// never reached? FIXME maybe use config.KubeConfigValuesKey or config.ImportTokenSecretValuesKey
newData := map[string]interface{}{}
if err := yaml.Unmarshal(values, &newData); err != nil {
return data
}
data = map[string][]byte{}
for k, v := range newData {
if s, ok := v.(string); ok {
data[k] = []byte(s)
}
}
return data
}
// createClientConfigFromSecret reads the fleet-agent-bootstrap secret and
// creates a clientConfig to access the upstream cluster
func createClientConfigFromSecret(secret *corev1.Secret) clientcmd.ClientConfig {
data := values(secret.Data)
apiServerURL := string(data[config.APIServerURLKey])
apiServerCA := data[config.APIServerCAKey]
namespace := string(data[ClusterNamespace])
token := string(data[Token])
if _, err := http.Get(apiServerURL); err == nil {
apiServerCA = nil
}
cfg := clientcmdapi.Config{
Clusters: map[string]*clientcmdapi.Cluster{
"cluster": {
Server: apiServerURL,
CertificateAuthorityData: apiServerCA,
},
},
AuthInfos: map[string]*clientcmdapi.AuthInfo{
"user": {
Token: token,
},
},
Contexts: map[string]*clientcmdapi.Context{
"default": {
Cluster: "cluster",
AuthInfo: "user",
Namespace: namespace,
},
},
CurrentContext: "default",
}
return clientcmd.NewDefaultClientConfig(cfg, &clientcmd.ConfigOverrides{})
}
func testClientConfig(cfg []byte) error {
cc, err := clientcmd.NewClientConfigFromBytes(cfg)
if err != nil {
return err
}
ns, _, err := cc.Namespace()
if err != nil {
return err
}
rest, err := cc.ClientConfig()
if err != nil {
return err
}
fc, err := fleetcontrollers.NewFactoryFromConfig(rest)
if err != nil {
return err
}
_, err = fc.Fleet().V1alpha1().BundleDeployment().List(ns, metav1.ListOptions{})
return err
}
func updateClientConfig(cc clientcmd.ClientConfig, token, ns string) ([]byte, error) {
raw, err := cc.RawConfig()
if err != nil {
return nil, err
}
for _, v := range raw.AuthInfos {
v.Token = token
}
for _, v := range raw.Contexts {
v.Namespace = ns
}
return clientcmd.Write(raw)
}