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server: don't set CNI config readinessindicatorfile when using ConfigManager

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For whatever reason calling os.Stat() on the readiness indicator file
from CmdAdd()/CmdDel() when multus is running in server mode and is
containerized often returns "file not found", which triggers the
polling behavior of GetReadinessIndicatorFile(). This greatly delays
CNI operations that should be pretty quick. Even if an exponential
backoff is used, os.Stat() can still return "file not found"
multiple times, even though the file clearly exists.

But it turns out we don't need to check the readiness file in server
mode when running with MultusConfigFile == "auto". In this mode the
server starts the ConfigManager which (a) waits until the file exists
and (b) fsnotify watches the readiness and (c) exits the daemon
immediately if the file is deleted or moved.

This means we can assume that while the daemon is running and the
server is handling CNI requests that the readiness file exists;
otherwise the daemon would have exited. Thus CmdAdd/CmdDel don't
need to run a lot of possibly failing os.Stat() calls in the CNI
hot paths.

Signed-off-by: Dan Williams <dcbw@redhat.com>
This commit is contained in:
Dan Williams
2023-09-12 20:40:28 -05:00
parent b0df7dd5e3
commit d9c06e99d1
6 changed files with 184 additions and 54 deletions
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48
cmd/multus-daemon/main.go
View File

@@ -83,7 +83,30 @@ func main() {
logging.Verbosef("Readiness Indicator file check done!")
}
if err := startMultusDaemon(ctx, daemonConf); err != nil {
var configManager *config.Manager
var ignoreReadinessIndicator bool
if multusConf.MultusConfigFile == "auto" {
if multusConf.CNIVersion == "" {
_ = logging.Errorf("the CNI version is a mandatory parameter when the '-multus-config-file=auto' option is used")
}
// Generate multus CNI config from current CNI config
configManager, err = config.NewManager(*multusConf)
if err != nil {
_ = logging.Errorf("failed to create the configuration manager for the primary CNI plugin: %v", err)
os.Exit(2)
}
// ConfigManager watches the readiness indicator file (if configured)
// and exits the daemon when that is removed. The CNIServer does
// not need to re-do that check every CNI operation
ignoreReadinessIndicator = true
} else {
if err := copyUserProvidedConfig(multusConf.MultusConfigFile, multusConf.CniConfigDir); err != nil {
logging.Errorf("failed to copy the user provided configuration %s: %v", multusConf.MultusConfigFile, err)
}
}
if err := startMultusDaemon(ctx, daemonConf, ignoreReadinessIndicator); err != nil {
logging.Panicf("failed start the multus thick-plugin listener: %v", err)
os.Exit(3)
}
@@ -96,25 +119,6 @@ func main() {
}
logging.Verbosef("API readiness check done!")
var configManager *config.Manager
// Generate multus CNI config from current CNI config
if multusConf.MultusConfigFile == "auto" {
if multusConf.CNIVersion == "" {
_ = logging.Errorf("the CNI version is a mandatory parameter when the '-multus-config-file=auto' option is used")
}
configManager, err = config.NewManager(*multusConf)
if err != nil {
_ = logging.Errorf("failed to create the configuration manager for the primary CNI plugin: %v", err)
os.Exit(2)
}
} else {
if err := copyUserProvidedConfig(multusConf.MultusConfigFile, multusConf.CniConfigDir); err != nil {
logging.Errorf("failed to copy the user provided configuration %s: %v", multusConf.MultusConfigFile, err)
}
}
signalCh := make(chan os.Signal, 16)
signal.Notify(signalCh, syscall.SIGINT, syscall.SIGTERM)
go func() {
@@ -146,7 +150,7 @@ func waitUntilAPIReady(socketPath string) error {
})
}
func startMultusDaemon(ctx context.Context, daemonConfig *srv.ControllerNetConf) error {
func startMultusDaemon(ctx context.Context, daemonConfig *srv.ControllerNetConf, ignoreReadinessIndicator bool) error {
if user, err := user.Current(); err != nil || user.Uid != "0" {
return fmt.Errorf("failed to run multus-daemon with root: %v, now running in uid: %s", err, user.Uid)
}
@@ -155,7 +159,7 @@ func startMultusDaemon(ctx context.Context, daemonConfig *srv.ControllerNetConf)
return fmt.Errorf("failed to prepare the cni-socket for communicating with the shim: %w", err)
}
server, err := srv.NewCNIServer(daemonConfig, daemonConfig.ConfigFileContents)
server, err := srv.NewCNIServer(daemonConfig, daemonConfig.ConfigFileContents, ignoreReadinessIndicator)
if err != nil {
return fmt.Errorf("failed to create the server: %v", err)
}