daemon/reload.go
package daemon // import "github.com/docker/docker/daemon"
import (
"context"
"encoding/json"
"fmt"
"strconv"
"github.com/containerd/log"
"github.com/docker/docker/api/types/events"
"github.com/hashicorp/go-multierror"
"github.com/mitchellh/copystructure"
"github.com/docker/docker/daemon/config"
)
// reloadTxn is used to defer side effects of a config reload.
type reloadTxn struct {
onCommit, onRollback []func() error
}
// OnCommit defers a function to be called when a config reload is being finalized.
// The error returned from cb is purely informational.
func (tx *reloadTxn) OnCommit(cb func() error) {
tx.onCommit = append(tx.onCommit, cb)
}
// OnRollback defers a function to be called when a config reload is aborted.
// The error returned from cb is purely informational.
func (tx *reloadTxn) OnRollback(cb func() error) {
tx.onCommit = append(tx.onRollback, cb)
}
func (tx *reloadTxn) run(cbs []func() error) error {
tx.onCommit = nil
tx.onRollback = nil
var res *multierror.Error
for _, cb := range cbs {
res = multierror.Append(res, cb())
}
return res.ErrorOrNil()
}
// Commit calls all functions registered with OnCommit.
// Any errors returned by the functions are collated into a
// *github.com/hashicorp/go-multierror.Error value.
func (tx *reloadTxn) Commit() error {
return tx.run(tx.onCommit)
}
// Rollback calls all functions registered with OnRollback.
// Any errors returned by the functions are collated into a
// *github.com/hashicorp/go-multierror.Error value.
func (tx *reloadTxn) Rollback() error {
return tx.run(tx.onRollback)
}
// Reload modifies the live daemon configuration from conf.
// conf is assumed to be a validated configuration.
//
// These are the settings that Reload changes:
// - Platform runtime
// - Daemon debug log level
// - Daemon max concurrent downloads
// - Daemon max concurrent uploads
// - Daemon max download attempts
// - Daemon shutdown timeout (in seconds)
// - Cluster discovery (reconfigure and restart)
// - Daemon labels
// - Insecure registries
// - Registry mirrors
// - Daemon live restore
func (daemon *Daemon) Reload(conf *config.Config) error {
daemon.configReload.Lock()
defer daemon.configReload.Unlock()
copied, err := copystructure.Copy(daemon.config().Config)
if err != nil {
return err
}
newCfg := &configStore{
Config: copied.(config.Config),
}
attributes := map[string]string{}
// Ideally reloading should be transactional: the reload either completes
// successfully, or the daemon config and state are left untouched. We use a
// two-phase commit protocol to achieve this. Any fallible reload operation is
// split into two phases. The first phase performs all the fallible operations
// and mutates the newCfg copy. The second phase atomically swaps newCfg into
// the live daemon configuration and executes any commit functions the first
// phase registered to apply the side effects. If any first-phase returns an
// error, the reload transaction is rolled back by discarding newCfg and
// executing any registered rollback functions.
var txn reloadTxn
for _, reload := range []func(txn *reloadTxn, newCfg *configStore, conf *config.Config, attributes map[string]string) error{
daemon.reloadPlatform,
daemon.reloadDebug,
daemon.reloadMaxConcurrentDownloadsAndUploads,
daemon.reloadMaxDownloadAttempts,
daemon.reloadShutdownTimeout,
daemon.reloadFeatures,
daemon.reloadLabels,
daemon.reloadRegistryConfig,
daemon.reloadLiveRestore,
daemon.reloadNetworkDiagnosticPort,
} {
if err := reload(&txn, newCfg, conf, attributes); err != nil {
if rollbackErr := txn.Rollback(); rollbackErr != nil {
return multierror.Append(nil, err, rollbackErr)
}
return err
}
}
jsonString, _ := json.Marshal(&struct {
*config.Config
config.Proxies `json:"proxies"`
}{
Config: &newCfg.Config,
Proxies: config.Proxies{
HTTPProxy: config.MaskCredentials(newCfg.HTTPProxy),
HTTPSProxy: config.MaskCredentials(newCfg.HTTPSProxy),
NoProxy: config.MaskCredentials(newCfg.NoProxy),
},
})
log.G(context.TODO()).Infof("Reloaded configuration: %s", jsonString)
daemon.configStore.Store(newCfg)
daemon.LogDaemonEventWithAttributes(events.ActionReload, attributes)
return txn.Commit()
}
func marshalAttributeSlice(v []string) string {
if v == nil {
return "[]"
}
b, err := json.Marshal(v)
if err != nil {
panic(err) // Should never happen as the input type is fixed.
}
return string(b)
}
// reloadDebug updates configuration with Debug option
// and updates the passed attributes
func (daemon *Daemon) reloadDebug(txn *reloadTxn, newCfg *configStore, conf *config.Config, attributes map[string]string) error {
// update corresponding configuration
if conf.IsValueSet("debug") {
newCfg.Debug = conf.Debug
}
// prepare reload event attributes with updatable configurations
attributes["debug"] = strconv.FormatBool(newCfg.Debug)
return nil
}
// reloadMaxConcurrentDownloadsAndUploads updates configuration with max concurrent
// download and upload options and updates the passed attributes
func (daemon *Daemon) reloadMaxConcurrentDownloadsAndUploads(txn *reloadTxn, newCfg *configStore, conf *config.Config, attributes map[string]string) error {
// We always "reset" as the cost is lightweight and easy to maintain.
newCfg.MaxConcurrentDownloads = config.DefaultMaxConcurrentDownloads
newCfg.MaxConcurrentUploads = config.DefaultMaxConcurrentUploads
if conf.IsValueSet("max-concurrent-downloads") && conf.MaxConcurrentDownloads != 0 {
newCfg.MaxConcurrentDownloads = conf.MaxConcurrentDownloads
}
if conf.IsValueSet("max-concurrent-uploads") && conf.MaxConcurrentUploads != 0 {
newCfg.MaxConcurrentUploads = conf.MaxConcurrentUploads
}
txn.OnCommit(func() error {
if daemon.imageService != nil {
daemon.imageService.UpdateConfig(
newCfg.MaxConcurrentDownloads,
newCfg.MaxConcurrentUploads,
)
}
return nil
})
// prepare reload event attributes with updatable configurations
attributes["max-concurrent-downloads"] = strconv.Itoa(newCfg.MaxConcurrentDownloads)
attributes["max-concurrent-uploads"] = strconv.Itoa(newCfg.MaxConcurrentUploads)
log.G(context.TODO()).Debug("Reset Max Concurrent Downloads: ", attributes["max-concurrent-downloads"])
log.G(context.TODO()).Debug("Reset Max Concurrent Uploads: ", attributes["max-concurrent-uploads"])
return nil
}
// reloadMaxDownloadAttempts updates configuration with max concurrent
// download attempts when a connection is lost and updates the passed attributes
func (daemon *Daemon) reloadMaxDownloadAttempts(txn *reloadTxn, newCfg *configStore, conf *config.Config, attributes map[string]string) error {
// We always "reset" as the cost is lightweight and easy to maintain.
newCfg.MaxDownloadAttempts = config.DefaultDownloadAttempts
if conf.IsValueSet("max-download-attempts") && conf.MaxDownloadAttempts != 0 {
newCfg.MaxDownloadAttempts = conf.MaxDownloadAttempts
}
// prepare reload event attributes with updatable configurations
attributes["max-download-attempts"] = strconv.Itoa(newCfg.MaxDownloadAttempts)
log.G(context.TODO()).Debug("Reset Max Download Attempts: ", attributes["max-download-attempts"])
return nil
}
// reloadShutdownTimeout updates configuration with daemon shutdown timeout option
// and updates the passed attributes
func (daemon *Daemon) reloadShutdownTimeout(txn *reloadTxn, newCfg *configStore, conf *config.Config, attributes map[string]string) error {
// update corresponding configuration
if conf.IsValueSet("shutdown-timeout") {
newCfg.ShutdownTimeout = conf.ShutdownTimeout
log.G(context.TODO()).Debugf("Reset Shutdown Timeout: %d", newCfg.ShutdownTimeout)
}
// prepare reload event attributes with updatable configurations
attributes["shutdown-timeout"] = strconv.Itoa(newCfg.ShutdownTimeout)
return nil
}
// reloadLabels updates configuration with engine labels
// and updates the passed attributes
func (daemon *Daemon) reloadLabels(txn *reloadTxn, newCfg *configStore, conf *config.Config, attributes map[string]string) error {
// update corresponding configuration
if conf.IsValueSet("labels") {
newCfg.Labels = conf.Labels
}
// prepare reload event attributes with updatable configurations
attributes["labels"] = marshalAttributeSlice(newCfg.Labels)
return nil
}
// reloadRegistryConfig updates the configuration with registry options
// and updates the passed attributes.
func (daemon *Daemon) reloadRegistryConfig(txn *reloadTxn, newCfg *configStore, conf *config.Config, attributes map[string]string) error {
// Update corresponding configuration.
if conf.IsValueSet("allow-nondistributable-artifacts") {
newCfg.ServiceOptions.AllowNondistributableArtifacts = conf.AllowNondistributableArtifacts
}
if conf.IsValueSet("insecure-registries") {
newCfg.ServiceOptions.InsecureRegistries = conf.InsecureRegistries
}
if conf.IsValueSet("registry-mirrors") {
newCfg.ServiceOptions.Mirrors = conf.Mirrors
}
commit, err := daemon.registryService.ReplaceConfig(newCfg.ServiceOptions)
if err != nil {
return err
}
txn.OnCommit(func() error { commit(); return nil })
attributes["allow-nondistributable-artifacts"] = marshalAttributeSlice(newCfg.ServiceOptions.AllowNondistributableArtifacts)
attributes["insecure-registries"] = marshalAttributeSlice(newCfg.ServiceOptions.InsecureRegistries)
attributes["registry-mirrors"] = marshalAttributeSlice(newCfg.ServiceOptions.Mirrors)
return nil
}
// reloadLiveRestore updates configuration with live restore option
// and updates the passed attributes
func (daemon *Daemon) reloadLiveRestore(txn *reloadTxn, newCfg *configStore, conf *config.Config, attributes map[string]string) error {
// update corresponding configuration
if conf.IsValueSet("live-restore") {
newCfg.LiveRestoreEnabled = conf.LiveRestoreEnabled
}
// prepare reload event attributes with updatable configurations
attributes["live-restore"] = strconv.FormatBool(newCfg.LiveRestoreEnabled)
return nil
}
// reloadNetworkDiagnosticPort updates the network controller starting the diagnostic if the config is valid
func (daemon *Daemon) reloadNetworkDiagnosticPort(txn *reloadTxn, newCfg *configStore, conf *config.Config, attributes map[string]string) error {
txn.OnCommit(func() error {
if conf == nil || daemon.netController == nil || !conf.IsValueSet("network-diagnostic-port") ||
conf.NetworkDiagnosticPort < 1 || conf.NetworkDiagnosticPort > 65535 {
// If there is no config make sure that the diagnostic is off
if daemon.netController != nil {
daemon.netController.StopDiagnostic()
}
return nil
}
// Enable the network diagnostic if the flag is set with a valid port within the range
log.G(context.TODO()).WithFields(log.Fields{"port": conf.NetworkDiagnosticPort, "ip": "127.0.0.1"}).Warn("Starting network diagnostic server")
daemon.netController.StartDiagnostic(conf.NetworkDiagnosticPort)
return nil
})
return nil
}
// reloadFeatures updates configuration with enabled/disabled features
func (daemon *Daemon) reloadFeatures(txn *reloadTxn, newCfg *configStore, conf *config.Config, attributes map[string]string) error {
// update corresponding configuration
// note that we allow features option to be entirely unset
newCfg.Features = conf.Features
// prepare reload event attributes with updatable configurations
attributes["features"] = fmt.Sprintf("%v", newCfg.Features)
return nil
}