k3s/pkg/cluster/bootstrap.go

601 lines
17 KiB
Go

package cluster
import (
"bytes"
"context"
"encoding/json"
"fmt"
"io"
"io/ioutil"
"net"
"os"
"path/filepath"
"reflect"
"strconv"
"strings"
"time"
"github.com/k3s-io/k3s/pkg/bootstrap"
"github.com/k3s-io/k3s/pkg/clientaccess"
"github.com/k3s-io/k3s/pkg/daemons/config"
"github.com/k3s-io/k3s/pkg/etcd"
"github.com/k3s-io/k3s/pkg/version"
"github.com/k3s-io/kine/pkg/client"
"github.com/k3s-io/kine/pkg/endpoint"
"github.com/otiai10/copy"
"github.com/pkg/errors"
"github.com/sirupsen/logrus"
)
// Bootstrap attempts to load a managed database driver, if one has been initialized or should be created/joined.
// It then checks to see if the cluster needs to load bootstrap data, and if so, loads data into the
// ControlRuntimeBoostrap struct, either via HTTP or from the datastore.
func (c *Cluster) Bootstrap(ctx context.Context, snapshot bool) error {
if err := c.assignManagedDriver(ctx); err != nil {
return err
}
shouldBootstrap, isInitialized, err := c.shouldBootstrapLoad(ctx)
if err != nil {
return err
}
c.shouldBootstrap = shouldBootstrap
if c.managedDB != nil {
if !snapshot {
isHTTP := c.config.JoinURL != "" && c.config.Token != ""
// For secondary servers, we attempt to connect and reconcile with the datastore.
// If that fails we fallback to the local etcd cluster start
if isInitialized && isHTTP && c.clientAccessInfo != nil {
if err := c.httpBootstrap(ctx); err == nil {
logrus.Info("Successfully reconciled with datastore")
return nil
}
logrus.Warnf("Unable to reconcile with datastore: %v", err)
}
// In the case of etcd, if the database has been initialized, it doesn't
// need to be bootstrapped however we still need to check the database
// and reconcile the bootstrap data. Below we're starting a temporary
// instance of etcd in the event that etcd certificates are unavailable,
// reading the data, and comparing that to the data on disk, all the while
// starting normal etcd.
if isInitialized {
if err := c.reconcileEtcd(ctx); err != nil {
logrus.Fatalf("Failed to reconcile with temporary etcd: %v", err)
}
}
}
}
if c.shouldBootstrap {
return c.bootstrap(ctx)
}
return nil
}
// shouldBootstrapLoad returns true if we need to load ControlRuntimeBootstrap data again and a second boolean
// indicating that the server has or has not been initialized, if etcd. This is controlled by a stamp file on
// disk that records successful bootstrap using a hash of the join token.
func (c *Cluster) shouldBootstrapLoad(ctx context.Context) (bool, bool, error) {
// Non-nil managedDB indicates that the database is either initialized, initializing, or joining
if c.managedDB != nil {
c.config.Runtime.HTTPBootstrap = true
isInitialized, err := c.managedDB.IsInitialized(ctx, c.config)
if err != nil {
return false, false, err
}
if isInitialized {
// If the database is initialized we skip bootstrapping; if the user wants to rejoin a
// cluster they need to delete the database.
logrus.Infof("Managed %s cluster bootstrap already complete and initialized", c.managedDB.EndpointName())
// This is a workaround for an issue that can be caused by terminating the cluster bootstrap before
// etcd is promoted from learner. Odds are we won't need this info, and we don't want to fail startup
// due to failure to retrieve it as this will break cold cluster restart, so we ignore any errors.
if c.config.JoinURL != "" && c.config.Token != "" {
c.clientAccessInfo, _ = clientaccess.ParseAndValidateTokenForUser(c.config.JoinURL, c.config.Token, "server")
}
return false, true, nil
} else if c.config.JoinURL == "" {
// Not initialized, not joining - must be initializing (cluster-init)
logrus.Infof("Managed %s cluster initializing", c.managedDB.EndpointName())
return false, false, nil
} else {
// Not initialized, but have a Join URL - fail if there's no token; if there is then validate it.
if c.config.Token == "" {
return false, false, errors.New(version.ProgramUpper + "_TOKEN is required to join a cluster")
}
// Fail if the token isn't syntactically valid, or if the CA hash on the remote server doesn't match
// the hash in the token. The password isn't actually checked until later when actually bootstrapping.
info, err := clientaccess.ParseAndValidateTokenForUser(c.config.JoinURL, c.config.Token, "server")
if err != nil {
return false, false, err
}
logrus.Infof("Managed %s cluster not yet initialized", c.managedDB.EndpointName())
c.clientAccessInfo = info
}
}
// No errors and no bootstrap stamp, need to bootstrap.
return true, false, nil
}
// isDirEmpty checks to see if the given directory
// is empty.
func isDirEmpty(name string) (bool, error) {
f, err := os.Open(name)
if err != nil {
return false, err
}
defer f.Close()
_, err = f.Readdir(1)
if err == io.EOF {
return true, nil
}
return false, err
}
// certDirsExist checks to see if the directories
// that contain the needed certificates exist.
func (c *Cluster) certDirsExist() error {
bootstrapDirs := []string{
"cred",
"tls",
"tls/etcd",
}
const (
missingDir = "missing %s directory from ${data-dir}"
emptyDir = "%s directory is empty"
)
for _, dir := range bootstrapDirs {
d := filepath.Join(c.config.DataDir, dir)
if _, err := os.Stat(d); os.IsNotExist(err) {
errMsg := fmt.Sprintf(missingDir, d)
logrus.Debug(errMsg)
return errors.New(errMsg)
}
ok, err := isDirEmpty(d)
if err != nil {
return err
}
if ok {
errMsg := fmt.Sprintf(emptyDir, d)
logrus.Debug(errMsg)
return errors.New(errMsg)
}
}
return nil
}
// migrateBootstrapData migrates bootstrap data from the old format to the new format.
func migrateBootstrapData(ctx context.Context, data io.Reader, files bootstrap.PathsDataformat) error {
logrus.Info("Migrating bootstrap data to new format")
var oldBootstrapData map[string][]byte
if err := json.NewDecoder(data).Decode(&oldBootstrapData); err != nil {
// if this errors here, we can assume that the error being thrown
// is not related to needing to perform a migration.
return err
}
// iterate through the old bootstrap data structure
// and copy into the new bootstrap data structure
for k, v := range oldBootstrapData {
files[k] = bootstrap.File{
Content: v,
}
}
return nil
}
const systemTimeSkew = int64(3)
// isMigrated checks to see if the given bootstrap data
// is in the latest format.
func isMigrated(buf io.ReadSeeker, files *bootstrap.PathsDataformat) bool {
buf.Seek(0, 0)
defer buf.Seek(0, 0)
if err := json.NewDecoder(buf).Decode(files); err != nil {
// This will fail if data is being pulled from old an cluster since
// older clusters used a map[string][]byte for the data structure.
// Therefore, we need to perform a migration to the newer bootstrap
// format; bootstrap.BootstrapFile.
return false
}
return true
}
// ReconcileBootstrapData is called before any data is saved to the
// datastore or locally. It checks to see if the contents of the
// bootstrap data in the datastore is newer than on disk or different
// and depending on where the difference is. If the datastore is newer,
// then the data will be written to disk. If the data on disk is newer,
// k3s will exit with an error.
func (c *Cluster) ReconcileBootstrapData(ctx context.Context, buf io.ReadSeeker, crb *config.ControlRuntimeBootstrap, isHTTP bool) error {
logrus.Info("Reconciling bootstrap data between datastore and disk")
if err := c.certDirsExist(); err != nil {
// we need to see if the data has been migrated before writing to disk. This
// is because the data may have been given to us via the HTTP bootstrap process
// from an older version of k3s. That version might not have the new data format
// and we should write the correct format.
files := make(bootstrap.PathsDataformat)
if !isMigrated(buf, &files) {
if err := migrateBootstrapData(ctx, buf, files); err != nil {
return err
}
buf.Seek(0, 0)
}
logrus.Debugf("One or more certificate directories do not exist; writing data to disk from datastore")
return bootstrap.WriteToDiskFromStorage(files, crb)
}
var dbRawData []byte
if c.managedDB != nil && !isHTTP {
token := c.config.Token
if token == "" {
tokenFromFile, err := readTokenFromFile(c.config.Runtime.ServerToken, c.config.Runtime.ServerCA, c.config.DataDir)
if err != nil {
return err
}
if tokenFromFile == "" {
// at this point this is a fresh start in a non-managed environment
c.saveBootstrap = true
return nil
}
token = tokenFromFile
}
normalizedToken, err := normalizeToken(token)
if err != nil {
return err
}
var value *client.Value
storageClient, err := client.New(c.config.Runtime.EtcdConfig)
if err != nil {
return err
}
defer storageClient.Close()
ticker := time.NewTicker(5 * time.Second)
defer ticker.Stop()
RETRY:
for {
value, c.saveBootstrap, err = getBootstrapKeyFromStorage(ctx, storageClient, normalizedToken, token)
if err != nil {
if strings.Contains(err.Error(), "not supported for learner") {
for range ticker.C {
continue RETRY
}
}
return err
}
if value == nil {
return nil
}
dbRawData, err = decrypt(normalizedToken, value.Data)
if err != nil {
return err
}
break
}
buf = bytes.NewReader(dbRawData)
}
paths, err := bootstrap.ObjToMap(crb)
if err != nil {
return err
}
files := make(bootstrap.PathsDataformat)
if !isMigrated(buf, &files) {
if err := migrateBootstrapData(ctx, buf, files); err != nil {
return err
}
buf.Seek(0, 0)
}
type update struct {
db, disk, conflict bool
}
var updateDisk bool
results := make(map[string]update)
for pathKey, fileData := range files {
path, ok := paths[pathKey]
if !ok || path == "" {
logrus.Warnf("Unable to lookup path to reconcile %s", pathKey)
continue
}
logrus.Debugf("Reconciling %s at '%s'", pathKey, path)
f, err := os.Open(path)
if err != nil {
if os.IsNotExist(err) {
logrus.Warn(path + " doesn't exist. continuing...")
updateDisk = true
continue
}
return err
}
defer f.Close()
fData, err := ioutil.ReadAll(f)
if err != nil {
return err
}
if !bytes.Equal(fileData.Content, fData) {
info, err := os.Stat(path)
if err != nil {
return err
}
switch {
case info.ModTime().Unix()-files[pathKey].Timestamp.Unix() >= systemTimeSkew:
if _, ok := results[path]; !ok {
results[path] = update{
db: true,
}
}
for pk := range files {
p, ok := paths[pk]
if !ok {
continue
}
if filepath.Base(p) == info.Name() {
continue
}
i, err := os.Stat(p)
if err != nil {
return err
}
if i.ModTime().Unix()-files[pk].Timestamp.Unix() >= systemTimeSkew {
if _, ok := results[path]; !ok {
results[path] = update{
conflict: true,
}
}
}
}
case info.ModTime().Unix()-files[pathKey].Timestamp.Unix() <= systemTimeSkew:
if _, ok := results[info.Name()]; !ok {
results[path] = update{
disk: true,
}
}
for pk := range files {
p, ok := paths[pk]
if !ok {
continue
}
if filepath.Base(p) == info.Name() {
continue
}
i, err := os.Stat(p)
if err != nil {
return err
}
if i.ModTime().Unix()-files[pk].Timestamp.Unix() <= systemTimeSkew {
if _, ok := results[path]; !ok {
results[path] = update{
conflict: true,
}
}
}
}
default:
if _, ok := results[path]; ok {
results[path] = update{}
}
}
}
}
if c.config.ClusterReset {
serverTLSDir := filepath.Join(c.config.DataDir, "tls")
tlsBackupDir := filepath.Join(c.config.DataDir, "tls-"+strconv.Itoa(int(time.Now().Unix())))
logrus.Infof("Cluster reset: backing up certificates directory to " + tlsBackupDir)
if _, err := os.Stat(serverTLSDir); err != nil {
return err
}
if err := copy.Copy(serverTLSDir, tlsBackupDir); err != nil {
return err
}
}
var newerOnDisk []string
for path, res := range results {
switch {
case res.disk:
updateDisk = true
logrus.Warn("Datastore newer than " + path)
case res.db:
if c.config.ClusterReset {
logrus.Infof("Cluster reset: replacing file on disk: " + path)
updateDisk = true
continue
}
newerOnDisk = append(newerOnDisk, path)
case res.conflict:
logrus.Warnf("Datastore / disk conflict: %s newer than in the datastore", path)
}
}
if len(newerOnDisk) > 0 {
logrus.Fatal(strings.Join(newerOnDisk, ", ") + " newer than datastore and could cause a cluster outage. Remove the file(s) from disk and restart to be recreated from datastore.")
}
if updateDisk {
logrus.Warn("Updating bootstrap data on disk from datastore")
return bootstrap.WriteToDiskFromStorage(files, crb)
}
return nil
}
// httpBootstrap retrieves bootstrap data (certs and keys, etc) from the remote server via HTTP
// and loads it into the ControlRuntimeBootstrap struct. Unlike the storage bootstrap path,
// this data does not need to be decrypted since it is generated on-demand by an existing server.
func (c *Cluster) httpBootstrap(ctx context.Context) error {
content, err := c.clientAccessInfo.Get("/v1-" + version.Program + "/server-bootstrap")
if err != nil {
return err
}
return c.ReconcileBootstrapData(ctx, bytes.NewReader(content), &c.config.Runtime.ControlRuntimeBootstrap, true)
}
func (c *Cluster) retrieveInitializedDBdata(ctx context.Context) (*bytes.Buffer, error) {
var buf bytes.Buffer
if err := bootstrap.ReadFromDisk(&buf, &c.config.Runtime.ControlRuntimeBootstrap); err != nil {
return nil, err
}
return &buf, nil
}
// bootstrap performs cluster bootstrapping, either via HTTP (for managed databases) or direct load from datastore.
func (c *Cluster) bootstrap(ctx context.Context) error {
c.joining = true
// bootstrap managed database via HTTPS
if c.config.Runtime.HTTPBootstrap {
// Assuming we should just compare on managed databases
if err := c.compareConfig(); err != nil {
return errors.Wrap(err, "failed to validate server configuration")
}
return c.httpBootstrap(ctx)
}
// Bootstrap directly from datastore
return c.storageBootstrap(ctx)
}
// Snapshot is a proxy method to call the snapshot method on the managedb
// interface for etcd clusters.
func (c *Cluster) Snapshot(ctx context.Context, config *config.Control) error {
if c.managedDB == nil {
return errors.New("unable to perform etcd snapshot on non-etcd system")
}
return c.managedDB.Snapshot(ctx, config)
}
// compareConfig verifies that the config of the joining control plane node coincides with the cluster's config
func (c *Cluster) compareConfig() error {
token := c.config.AgentToken
if token == "" {
token = c.config.Token
}
agentClientAccessInfo, err := clientaccess.ParseAndValidateTokenForUser(c.config.JoinURL, token, "node")
if err != nil {
return err
}
serverConfig, err := agentClientAccessInfo.Get("/v1-" + version.Program + "/config")
if err != nil {
return err
}
clusterControl := &config.Control{}
if err := json.Unmarshal(serverConfig, clusterControl); err != nil {
return err
}
// We are saving IPs of ClusterIPRanges and ServiceIPRanges in 4-bytes representation but json decodes in 16-byte
ipsTo16Bytes(c.config.CriticalControlArgs.ClusterIPRanges)
ipsTo16Bytes(c.config.CriticalControlArgs.ServiceIPRanges)
if !reflect.DeepEqual(clusterControl.CriticalControlArgs, c.config.CriticalControlArgs) {
logrus.Debugf("This is the server CriticalControlArgs: %#v", clusterControl.CriticalControlArgs)
logrus.Debugf("This is the local CriticalControlArgs: %#v", c.config.CriticalControlArgs)
return errors.New("critical configuration value mismatch")
}
return nil
}
// ipsTo16Bytes makes sure the IPs in the []*net.IPNet slice are represented in 16-byte format
func ipsTo16Bytes(mySlice []*net.IPNet) {
for _, ipNet := range mySlice {
ipNet.IP = ipNet.IP.To16()
}
}
// reconcileEtcd starts a temporary single-member etcd cluster using a copy of the
// etcd database, and uses it to reconcile bootstrap data. This is necessary
// because the full etcd cluster may not have quorum during startup, but we still
// need to extract data from the datastore.
func (c *Cluster) reconcileEtcd(ctx context.Context) error {
logrus.Info("Starting temporary etcd to reconcile with datastore")
tempConfig := endpoint.ETCDConfig{Endpoints: []string{"http://127.0.0.1:2399"}}
originalConfig := c.config.Runtime.EtcdConfig
c.config.Runtime.EtcdConfig = tempConfig
reconcileCtx, cancel := context.WithCancel(ctx)
defer func() {
cancel()
c.config.Runtime.EtcdConfig = originalConfig
}()
e := etcd.NewETCD()
if err := e.SetControlConfig(reconcileCtx, c.config); err != nil {
return err
}
if err := e.StartEmbeddedTemporary(reconcileCtx); err != nil {
return err
}
for {
if err := e.Test(reconcileCtx); err != nil && !errors.Is(err, etcd.ErrNotMember) {
logrus.Infof("Failed to test temporary data store connection: %v", err)
} else {
logrus.Info(e.EndpointName() + " temporary data store connection OK")
break
}
select {
case <-time.After(5 * time.Second):
case <-reconcileCtx.Done():
break
}
}
data, err := c.retrieveInitializedDBdata(reconcileCtx)
if err != nil {
return err
}
return c.ReconcileBootstrapData(reconcileCtx, bytes.NewReader(data.Bytes()), &c.config.Runtime.ControlRuntimeBootstrap, false)
}