Remove configuration hot reloading from target allocator (#2425)

.chloggen/ta_removehotreload.yaml

@@ -0,0 +1,16 @@
+# One of 'breaking', 'deprecation', 'new_component', 'enhancement', 'bug_fix'
+change_type: breaking
+
+# The name of the component, or a single word describing the area of concern, (e.g. operator, target allocator, github action)
+component: target allocator
+
+# A brief description of the change. Surround your text with quotes ("") if it needs to start with a backtick (`).
+note: Remove configuration hot reloading from target allocator
+
+# One or more tracking issues related to the change
+issues: [2032]
+
+# (Optional) One or more lines of additional information to render under the primary note.
+# These lines will be padded with 2 spaces and then inserted directly into the document.
+# Use pipe (|) for multiline entries.
+subtext: This only affects use of target allocator without the operator.

cmd/otel-allocator/config/config.go

@@ -43,7 +43,6 @@ type Config struct {
 	KubeConfigFilePath     string             `yaml:"kube_config_file_path,omitempty"`
 	ClusterConfig          *rest.Config       `yaml:"-"`
 	RootLogger             logr.Logger        `yaml:"-"`
-	ReloadConfig           bool               `yaml:"-"`
 	LabelSelector          map[string]string  `yaml:"label_selector,omitempty"`
 	PromConfig             *promconfig.Config `yaml:"config"`
 	AllocationStrategy     *string            `yaml:"allocation_strategy,omitempty"`
@@ -111,11 +110,6 @@ func LoadFromCLI(target *Config, flagSet *pflag.FlagSet) error {
 		return err
 	}
 
-	target.ReloadConfig, err = getConfigReloadEnabled(flagSet)
-	if err != nil {
-		return err
-	}
-
 	return nil
 }
 
@@ -139,33 +133,33 @@ func CreateDefaultConfig() Config {
 	}
 }
 
-func Load() (*Config, string, error) {
+func Load() (*Config, error) {
 	var err error
 
 	flagSet := getFlagSet(pflag.ExitOnError)
 	err = flagSet.Parse(os.Args)
 	if err != nil {
-		return nil, "", err
+		return nil, err
 	}
 
 	config := CreateDefaultConfig()
 
 	// load the config from the config file
 	configFilePath, err := getConfigFilePath(flagSet)
 	if err != nil {
-		return nil, "", err
+		return nil, err
 	}
 	err = LoadFromFile(configFilePath, &config)
 	if err != nil {
-		return nil, "", err
+		return nil, err
 	}
 
 	err = LoadFromCLI(&config, flagSet)
 	if err != nil {
-		return nil, "", err
+		return nil, err
 	}
 
-	return &config, configFilePath, nil
+	return &config, nil
 }
 
 // ValidateConfig validates the cli and file configs together.

cmd/otel-allocator/config/flags.go

@@ -30,7 +30,6 @@ const (
 	listenAddrFlagName          = "listen-addr"
 	prometheusCREnabledFlagName = "enable-prometheus-cr-watcher"
 	kubeConfigPathFlagName      = "kubeconfig-path"
-	reloadConfigFlagName        = "reload-config"
 )
 
 // We can't bind this flag to our FlagSet, so we need to handle it separately.
@@ -42,7 +41,6 @@ func getFlagSet(errorHandling pflag.ErrorHandling) *pflag.FlagSet {
 	flagSet.String(listenAddrFlagName, ":8080", "The address where this service serves.")
 	flagSet.Bool(prometheusCREnabledFlagName, false, "Enable Prometheus CRs as target sources")
 	flagSet.String(kubeConfigPathFlagName, filepath.Join(homedir.HomeDir(), ".kube", "config"), "absolute path to the KubeconfigPath file")
-	flagSet.Bool(reloadConfigFlagName, false, "Enable automatic configuration reloading. This functionality is deprecated and will be removed in a future release.")
 	zapFlagSet := flag.NewFlagSet("", flag.ErrorHandling(errorHandling))
 	zapCmdLineOpts.BindFlags(zapFlagSet)
 	flagSet.AddGoFlagSet(zapFlagSet)
@@ -64,7 +62,3 @@ func getListenAddr(flagSet *pflag.FlagSet) (string, error) {
 func getPrometheusCREnabled(flagSet *pflag.FlagSet) (bool, error) {
 	return flagSet.GetBool(prometheusCREnabledFlagName)
 }
-
-func getConfigReloadEnabled(flagSet *pflag.FlagSet) (bool, error) {
-	return flagSet.GetBool(reloadConfigFlagName)
-}

cmd/otel-allocator/config/flags_test.go

@@ -64,12 +64,6 @@ func TestFlagGetters(t *testing.T) {
 			expectedValue: true,
 			getterFunc:    func(fs *pflag.FlagSet) (interface{}, error) { return getPrometheusCREnabled(fs) },
 		},
-		{
-			name:          "GetConfigReloadEnabled",
-			flagArgs:      []string{"--" + reloadConfigFlagName, "true"},
-			expectedValue: true,
-			getterFunc:    func(fs *pflag.FlagSet) (interface{}, error) { return getConfigReloadEnabled(fs) },
-		},
 		{
 			name:        "InvalidFlag",
 			flagArgs:    []string{"--invalid-flag", "value"},

cmd/otel-allocator/main.go

@@ -54,7 +54,6 @@ func main() {
 		allocator        allocation.Allocator
 		discoveryManager *discovery.Manager
 		collectorWatcher *collector.Client
-		fileWatcher      allocatorWatcher.Watcher
 		promWatcher      allocatorWatcher.Watcher
 		targetDiscoverer *target.Discoverer
 
@@ -65,7 +64,7 @@ func main() {
 		interrupts      = make(chan os.Signal, 1)
 		errChan         = make(chan error)
 	)
-	cfg, configFilePath, err := config.Load()
+	cfg, err := config.Load()
 	if err != nil {
 		fmt.Printf("Failed to load config: %v", err)
 		os.Exit(1)
@@ -99,13 +98,6 @@ func main() {
 		setupLog.Error(collectorWatcherErr, "Unable to initialize collector watcher")
 		os.Exit(1)
 	}
-	if cfg.ReloadConfig {
-		fileWatcher, err = allocatorWatcher.NewFileWatcher(setupLog.WithName("file-watcher"), configFilePath)
-		if err != nil {
-			setupLog.Error(err, "Can't start the file watcher")
-			os.Exit(1)
-		}
-	}
 	signal.Notify(interrupts, os.Interrupt, syscall.SIGINT, syscall.SIGTERM)
 	defer close(interrupts)
 
@@ -129,21 +121,6 @@ func main() {
 				}
 			})
 	}
-	if cfg.ReloadConfig {
-		runGroup.Add(
-			func() error {
-				fileWatcherErr := fileWatcher.Watch(eventChan, errChan)
-				setupLog.Info("File watcher exited")
-				return fileWatcherErr
-			},
-			func(_ error) {
-				setupLog.Info("Closing file watcher")
-				fileWatcherErr := fileWatcher.Close()
-				if fileWatcherErr != nil {
-					setupLog.Error(fileWatcherErr, "file watcher failed to close")
-				}
-			})
-	}
 	runGroup.Add(
 		func() error {
 			discoveryManagerErr := discoveryManager.Run()