diff --git a/Makefile b/Makefile
index b50d97b97..f5bfb38ff 100644
--- a/Makefile
+++ b/Makefile
@@ -129,7 +129,7 @@ helm-lint:
 	helm lint --strict deployment/helm/node-feature-discovery/
 
 test:
-	$(GO_CMD) test ./cmd/... ./pkg/...
+	$(GO_CMD) test ./cmd/... ./pkg/... ./source/...
 
 e2e-test:
 	@if [ -z ${KUBECONFIG} ]; then echo "[ERR] KUBECONFIG missing, must be defined"; exit 1; fi
diff --git a/pkg/nfd-client/worker/nfd-worker-internal_test.go b/pkg/nfd-client/worker/nfd-worker-internal_test.go
index d2255cb9b..9070c0969 100644
--- a/pkg/nfd-client/worker/nfd-worker-internal_test.go
+++ b/pkg/nfd-client/worker/nfd-worker-internal_test.go
@@ -33,7 +33,6 @@ import (
 	"sigs.k8s.io/node-feature-discovery/pkg/utils"
 	"sigs.k8s.io/node-feature-discovery/source"
 	"sigs.k8s.io/node-feature-discovery/source/cpu"
-	"sigs.k8s.io/node-feature-discovery/source/fake"
 	"sigs.k8s.io/node-feature-discovery/source/kernel"
 	"sigs.k8s.io/node-feature-discovery/source/pci"
 )
@@ -96,15 +95,6 @@ func makeFakeFeatures(names []string) (source.FeatureLabels, Labels) {
 	return features, labels
 }
 
-func (w *nfdWorker) getSource(name string) source.LabelSource {
-	for _, s := range w.realSources {
-		if s.Name() == name {
-			return s
-		}
-	}
-	return nil
-}
-
 func TestConfigParse(t *testing.T) {
 	Convey("When parsing configuration", t, func() {
 		w, err := NewNfdWorker(&Args{})
@@ -130,7 +120,7 @@ func TestConfigParse(t *testing.T) {
 			Convey("overrides should take effect", func() {
 				So(worker.config.Core.NoPublish, ShouldBeTrue)
 
-				c := worker.getSource("cpu").GetConfig().(*cpu.Config)
+				c := source.GetConfigurableSource("cpu").GetConfig().(*cpu.Config)
 				So(c.Cpuid.AttributeBlacklist, ShouldResemble, []string{"foo", "bar"})
 			})
 		})
@@ -167,9 +157,9 @@ sources:
 
 				// Verify feature source config
 				So(err, ShouldBeNil)
-				c := worker.getSource("kernel").GetConfig()
+				c := source.GetConfigurableSource("kernel").GetConfig()
 				So(c.(*kernel.Config).ConfigOpts, ShouldResemble, []string{"DMI"})
-				c = worker.getSource("pci").GetConfig()
+				c = source.GetConfigurableSource("pci").GetConfig()
 				So(c.(*pci.Config).DeviceClassWhitelist, ShouldResemble, []string{"ff"})
 			})
 		})
@@ -189,9 +179,9 @@ sources:
 
 				// Verify feature source config
 				So(err, ShouldBeNil)
-				c := worker.getSource("kernel").GetConfig()
+				c := source.GetConfigurableSource("kernel").GetConfig()
 				So(c.(*kernel.Config).ConfigOpts, ShouldResemble, []string{"DMI"})
-				c = worker.getSource("pci").GetConfig()
+				c = source.GetConfigurableSource("pci").GetConfig()
 				So(c.(*pci.Config).DeviceClassWhitelist, ShouldResemble, []string{"03"})
 			})
 		})
@@ -318,7 +308,7 @@ func TestNewNfdWorker(t *testing.T) {
 			worker := w.(*nfdWorker)
 			So(worker.configure("", ""), ShouldBeNil)
 			Convey("all sources should be enabled and the whitelist regexp should be empty", func() {
-				So(len(worker.enabledSources), ShouldEqual, len(worker.realSources))
+				So(len(worker.enabledSources), ShouldEqual, len(source.GetAllLabelSources())-1)
 				So(worker.config.Core.LabelWhiteList, ShouldResemble, emptyRegexp)
 			})
 		})
@@ -333,7 +323,7 @@ func TestNewNfdWorker(t *testing.T) {
 			So(worker.configure("", ""), ShouldBeNil)
 			Convey("proper sources should be enabled", func() {
 				So(len(worker.enabledSources), ShouldEqual, 1)
-				So(worker.enabledSources[0], ShouldHaveSameTypeAs, &fake.Source{})
+				So(worker.enabledSources[0].Name(), ShouldEqual, "fake")
 				So(worker.config.Core.LabelWhiteList, ShouldResemble, emptyRegexp)
 			})
 		})
@@ -356,9 +346,9 @@ func TestNewNfdWorker(t *testing.T) {
 
 func TestCreateFeatureLabels(t *testing.T) {
 	Convey("When creating feature labels from the configured sources", t, func() {
-		fakeLabelSource := source.LabelSource(new(fake.Source))
-		fakeLabelSource.SetConfig(fakeLabelSource.NewConfig())
-		sources := []source.LabelSource{fakeLabelSource}
+		cs := source.GetConfigurableSource("fake")
+		cs.SetConfig(cs.NewConfig())
+		sources := []source.LabelSource{source.GetLabelSource("fake")}
 
 		Convey("When fake feature source is configured", func() {
 			emptyLabelWL := regexp.MustCompile("")
diff --git a/pkg/nfd-client/worker/nfd-worker.go b/pkg/nfd-client/worker/nfd-worker.go
index d34467c70..3d8c47770 100644
--- a/pkg/nfd-client/worker/nfd-worker.go
+++ b/pkg/nfd-client/worker/nfd-worker.go
@@ -23,6 +23,7 @@ import (
 	"os"
 	"path/filepath"
 	"regexp"
+	"sort"
 	"strings"
 	"time"
 
@@ -36,18 +37,20 @@ import (
 	"sigs.k8s.io/node-feature-discovery/pkg/utils"
 	"sigs.k8s.io/node-feature-discovery/pkg/version"
 	"sigs.k8s.io/node-feature-discovery/source"
-	"sigs.k8s.io/node-feature-discovery/source/cpu"
-	"sigs.k8s.io/node-feature-discovery/source/custom"
-	"sigs.k8s.io/node-feature-discovery/source/fake"
-	"sigs.k8s.io/node-feature-discovery/source/iommu"
-	"sigs.k8s.io/node-feature-discovery/source/kernel"
-	"sigs.k8s.io/node-feature-discovery/source/local"
-	"sigs.k8s.io/node-feature-discovery/source/memory"
-	"sigs.k8s.io/node-feature-discovery/source/network"
-	"sigs.k8s.io/node-feature-discovery/source/pci"
-	"sigs.k8s.io/node-feature-discovery/source/storage"
-	"sigs.k8s.io/node-feature-discovery/source/system"
-	"sigs.k8s.io/node-feature-discovery/source/usb"
+
+	// Register all source packages
+	_ "sigs.k8s.io/node-feature-discovery/source/cpu"
+	_ "sigs.k8s.io/node-feature-discovery/source/custom"
+	_ "sigs.k8s.io/node-feature-discovery/source/fake"
+	_ "sigs.k8s.io/node-feature-discovery/source/iommu"
+	_ "sigs.k8s.io/node-feature-discovery/source/kernel"
+	_ "sigs.k8s.io/node-feature-discovery/source/local"
+	_ "sigs.k8s.io/node-feature-discovery/source/memory"
+	_ "sigs.k8s.io/node-feature-discovery/source/network"
+	_ "sigs.k8s.io/node-feature-discovery/source/pci"
+	_ "sigs.k8s.io/node-feature-discovery/source/storage"
+	_ "sigs.k8s.io/node-feature-discovery/source/system"
+	_ "sigs.k8s.io/node-feature-discovery/source/usb"
 )
 
 // Global config
@@ -99,9 +102,7 @@ type nfdWorker struct {
 	client         pb.LabelerClient
 	configFilePath string
 	config         *NFDConfig
-	realSources    []source.LabelSource
 	stop           chan struct{} // channel for signaling stop
-	testSources    []source.LabelSource
 	enabledSources []source.LabelSource
 }
 
@@ -121,25 +122,7 @@ func NewNfdWorker(args *Args) (nfdclient.NfdClient, error) {
 
 		args:   *args,
 		config: &NFDConfig{},
-		realSources: []source.LabelSource{
-			&cpu.Source{},
-			&iommu.Source{},
-			&kernel.Source{},
-			&memory.Source{},
-			&network.Source{},
-			&pci.Source{},
-			&storage.Source{},
-			&system.Source{},
-			&usb.Source{},
-			&custom.Source{},
-			// local needs to be the last source so that it is able to override
-			// labels from other sources
-			&local.Source{},
-		},
-		testSources: []source.LabelSource{
-			&fake.Source{},
-		},
-		stop: make(chan struct{}, 1),
+		stop:   make(chan struct{}, 1),
 	}
 
 	if args.ConfigFile != "" {
@@ -301,36 +284,44 @@ func (w *nfdWorker) configureCore(c coreConfig) error {
 	}
 
 	// Determine enabled feature sources
-	sourceList := map[string]struct{}{}
-	all := false
-	for _, s := range c.Sources {
-		if s == "all" {
-			all = true
-			continue
+	enabled := make(map[string]source.LabelSource)
+	for _, name := range c.Sources {
+		if name == "all" {
+			for n, s := range source.GetAllLabelSources() {
+				if ts, ok := s.(source.TestSource); !ok || !ts.IsTestSource() {
+					enabled[n] = s
+				}
+			}
+		} else {
+			if s := source.GetLabelSource(name); s != nil {
+				enabled[name] = s
+			} else {
+				klog.Warningf("skipping unknown source %q specified in core.sources (or --sources)", name)
+			}
 		}
-		sourceList[strings.TrimSpace(s)] = struct{}{}
 	}
 
-	w.enabledSources = []source.LabelSource{}
-	for _, s := range w.realSources {
-		if _, enabled := sourceList[s.Name()]; all || enabled {
-			w.enabledSources = append(w.enabledSources, s)
-			delete(sourceList, s.Name())
-		}
+	w.enabledSources = make([]source.LabelSource, 0, len(enabled))
+	for _, s := range enabled {
+		w.enabledSources = append(w.enabledSources, s)
 	}
-	for _, s := range w.testSources {
-		if _, enabled := sourceList[s.Name()]; enabled {
-			w.enabledSources = append(w.enabledSources, s)
-			delete(sourceList, s.Name())
+
+	sort.Slice(w.enabledSources, func(i, j int) bool {
+		iP, jP := w.enabledSources[i].Priority(), w.enabledSources[j].Priority()
+		if iP != jP {
+			return iP < jP
 		}
-	}
-	if len(sourceList) > 0 {
-		names := make([]string, 0, len(sourceList))
-		for n := range sourceList {
-			names = append(names, n)
+		return w.enabledSources[i].Name() < w.enabledSources[j].Name()
+	})
+
+	if klog.V(1).Enabled() {
+		n := make([]string, len(w.enabledSources))
+		for i, s := range w.enabledSources {
+			n[i] = s.Name()
 		}
-		klog.Warningf("skipping unknown source(s) %q specified in core.sources (or --sources)", strings.Join(names, ", "))
+		klog.Infof("enabled label sources: %s", strings.Join(n, ", "))
 	}
+
 	return nil
 }
 
@@ -338,9 +329,9 @@ func (w *nfdWorker) configureCore(c coreConfig) error {
 func (w *nfdWorker) configure(filepath string, overrides string) error {
 	// Create a new default config
 	c := newDefaultConfig()
-	allSources := append(w.realSources, w.testSources...)
-	c.Sources = make(map[string]source.Config, len(allSources))
-	for _, s := range allSources {
+	confSources := source.GetAllConfigurableSources()
+	c.Sources = make(map[string]source.Config, len(confSources))
+	for _, s := range confSources {
 		c.Sources[s.Name()] = s.NewConfig()
 	}
 
@@ -388,8 +379,8 @@ func (w *nfdWorker) configure(filepath string, overrides string) error {
 		return err
 	}
 
-	// (Re-)configure all "real" sources, test sources are not configurable
-	for _, s := range allSources {
+	// (Re-)configure sources
+	for _, s := range confSources {
 		s.SetConfig(c.Sources[s.Name()])
 	}
 
@@ -432,8 +423,8 @@ func getFeatureLabels(source source.LabelSource, labelWhiteList regexp.Regexp) (
 
 	// Prefix for labels in the default namespace
 	prefix := source.Name() + "-"
-	switch source.(type) {
-	case *local.Source:
+	switch source.Name() {
+	case "local":
 		// Do not prefix labels from the hooks
 		prefix = ""
 	}
diff --git a/source/cpu/cpu.go b/source/cpu/cpu.go
index 1563b9235..c23fff4f3 100644
--- a/source/cpu/cpu.go
+++ b/source/cpu/cpu.go
@@ -78,22 +78,29 @@ type keyFilter struct {
 	whitelist bool
 }
 
-// Source implements LabelSource.
-type Source struct {
+// cpuSource implements the LabelSource and ConfigurableSource interfaces.
+type cpuSource struct {
 	config      *Config
 	cpuidFilter *keyFilter
 }
 
-func (s Source) Name() string { return Name }
+// Singleton source instance
+var (
+	src cpuSource
+	_   source.LabelSource        = &src
+	_   source.ConfigurableSource = &src
+)
+
+func (s *cpuSource) Name() string { return Name }
 
 // NewConfig method of the LabelSource interface
-func (s *Source) NewConfig() source.Config { return newDefaultConfig() }
+func (s *cpuSource) NewConfig() source.Config { return newDefaultConfig() }
 
 // GetConfig method of the LabelSource interface
-func (s *Source) GetConfig() source.Config { return s.config }
+func (s *cpuSource) GetConfig() source.Config { return s.config }
 
 // SetConfig method of the LabelSource interface
-func (s *Source) SetConfig(conf source.Config) {
+func (s *cpuSource) SetConfig(conf source.Config) {
 	switch v := conf.(type) {
 	case *Config:
 		s.config = v
@@ -103,7 +110,10 @@ func (s *Source) SetConfig(conf source.Config) {
 	}
 }
 
-func (s *Source) Discover() (source.FeatureLabels, error) {
+// Priority method of the LabelSource interface
+func (s *cpuSource) Priority() int { return 0 }
+
+func (s *cpuSource) Discover() (source.FeatureLabels, error) {
 	features := source.FeatureLabels{}
 
 	// Check if hyper-threading seems to be enabled
@@ -182,7 +192,7 @@ func haveThreadSiblings() (bool, error) {
 	return false, nil
 }
 
-func (s *Source) initCpuidFilter() {
+func (s *cpuSource) initCpuidFilter() {
 	newFilter := keyFilter{keys: map[string]struct{}{}}
 	if len(s.config.Cpuid.AttributeWhitelist) > 0 {
 		for _, k := range s.config.Cpuid.AttributeWhitelist {
@@ -210,3 +220,7 @@ func (f keyFilter) unmask(k string) bool {
 	}
 	return false
 }
+
+func init() {
+	source.Register(&src)
+}
diff --git a/source/custom/custom.go b/source/custom/custom.go
index b1bca0d94..6bfaf582a 100644
--- a/source/custom/custom.go
+++ b/source/custom/custom.go
@@ -51,22 +51,29 @@ func newDefaultConfig() *config {
 	return &config{}
 }
 
-// Source implements LabelSource.
-type Source struct {
+// customSource implements the LabelSource and ConfigurableSource interfaces.
+type customSource struct {
 	config *config
 }
 
+// Singleton source instance
+var (
+	src customSource
+	_   source.LabelSource        = &src
+	_   source.ConfigurableSource = &src
+)
+
 // Name returns the name of the feature source
-func (s Source) Name() string { return Name }
+func (s *customSource) Name() string { return Name }
 
 // NewConfig method of the LabelSource interface
-func (s *Source) NewConfig() source.Config { return newDefaultConfig() }
+func (s *customSource) NewConfig() source.Config { return newDefaultConfig() }
 
 // GetConfig method of the LabelSource interface
-func (s *Source) GetConfig() source.Config { return s.config }
+func (s *customSource) GetConfig() source.Config { return s.config }
 
 // SetConfig method of the LabelSource interface
-func (s *Source) SetConfig(conf source.Config) {
+func (s *customSource) SetConfig(conf source.Config) {
 	switch v := conf.(type) {
 	case *config:
 		s.config = v
@@ -75,8 +82,11 @@ func (s *Source) SetConfig(conf source.Config) {
 	}
 }
 
+// Priority method of the LabelSource interface
+func (s *customSource) Priority() int { return 10 }
+
 // Discover features
-func (s Source) Discover() (source.FeatureLabels, error) {
+func (s *customSource) Discover() (source.FeatureLabels, error) {
 	features := source.FeatureLabels{}
 	allFeatureConfig := append(getStaticFeatureConfig(), *s.config...)
 	allFeatureConfig = append(allFeatureConfig, getDirectoryFeatureConfig()...)
@@ -101,7 +111,7 @@ func (s Source) Discover() (source.FeatureLabels, error) {
 
 // Process a single feature by Matching on the defined rules.
 // A feature is present if all defined Rules in a MatchRule return a match.
-func (s Source) discoverFeature(feature FeatureSpec) (bool, error) {
+func (s *customSource) discoverFeature(feature FeatureSpec) (bool, error) {
 	for _, matchRules := range feature.MatchOn {
 
 		allRules := []rules.Rule{
@@ -136,3 +146,7 @@ func (s Source) discoverFeature(feature FeatureSpec) (bool, error) {
 	}
 	return false, nil
 }
+
+func init() {
+	source.Register(&src)
+}
diff --git a/source/fake/fake.go b/source/fake/fake.go
index 43e676b02..9d9f8d2aa 100644
--- a/source/fake/fake.go
+++ b/source/fake/fake.go
@@ -1,5 +1,5 @@
 /*
-Copyright 2017 The Kubernetes Authors.
+Copyright 2017-2021 The Kubernetes Authors.
 
 Licensed under the Apache License, Version 2.0 (the "License");
 you may not use this file except in compliance with the License.
@@ -40,22 +40,29 @@ func newDefaultConfig() *Config {
 	}
 }
 
-// Source implements LabelSource.
-type Source struct {
+// fakeSource implements the LabelSource and ConfigurableSource interfaces.
+type fakeSource struct {
 	config *Config
 }
 
+// Singleton source instance
+var (
+	src fakeSource
+	_   source.LabelSource        = &src
+	_   source.ConfigurableSource = &src
+)
+
 // Name returns an identifier string for this feature source.
-func (s Source) Name() string { return Name }
+func (s *fakeSource) Name() string { return Name }
 
 // NewConfig method of the LabelSource interface
-func (s *Source) NewConfig() source.Config { return newDefaultConfig() }
+func (s *fakeSource) NewConfig() source.Config { return newDefaultConfig() }
 
 // GetConfig method of the LabelSource interface
-func (s *Source) GetConfig() source.Config { return s.config }
+func (s *fakeSource) GetConfig() source.Config { return s.config }
 
 // SetConfig method of the LabelSource interface
-func (s *Source) SetConfig(conf source.Config) {
+func (s *fakeSource) SetConfig(conf source.Config) {
 	switch v := conf.(type) {
 	case *Config:
 		s.config = v
@@ -65,10 +72,13 @@ func (s *Source) SetConfig(conf source.Config) {
 }
 
 // Configure method of the LabelSource interface
-func (s Source) Configure([]byte) error { return nil }
+func (s *fakeSource) Configure([]byte) error { return nil }
+
+// Priority method of the LabelSource interface
+func (s *fakeSource) Priority() int { return 0 }
 
 // Discover returns feature names for some fake features.
-func (s Source) Discover() (source.FeatureLabels, error) {
+func (s *fakeSource) Discover() (source.FeatureLabels, error) {
 	// Adding three fake features.
 	features := make(source.FeatureLabels, len(s.config.Labels))
 	for k, v := range s.config.Labels {
@@ -77,3 +87,10 @@ func (s Source) Discover() (source.FeatureLabels, error) {
 
 	return features, nil
 }
+
+// IsTestSource method of the LabelSource interface
+func (s *fakeSource) IsTestSource() bool { return true }
+
+func init() {
+	source.Register(&src)
+}
diff --git a/source/iommu/iommu.go b/source/iommu/iommu.go
index 36849a847..f731bf934 100644
--- a/source/iommu/iommu.go
+++ b/source/iommu/iommu.go
@@ -1,5 +1,5 @@
 /*
-Copyright 2018 The Kubernetes Authors.
+Copyright 2018-2021 The Kubernetes Authors.
 
 Licensed under the Apache License, Version 2.0 (the "License");
 you may not use this file except in compliance with the License.
@@ -25,21 +25,21 @@ import (
 
 const Name = "iommu"
 
-// Source implements LabelSource.
-type Source struct{}
+// iommuSource implements the LabelSource interface.
+type iommuSource struct{}
 
-func (s Source) Name() string { return Name }
+func (s *iommuSource) Name() string { return Name }
 
-// NewConfig method of the LabelSource interface
-func (s *Source) NewConfig() source.Config { return nil }
+// Singleton source instance
+var (
+	src iommuSource
+	_   source.LabelSource = &src
+)
 
-// GetConfig method of the LabelSource interface
-func (s *Source) GetConfig() source.Config { return nil }
+// Priority method of the LabelSource interface
+func (s *iommuSource) Priority() int { return 0 }
 
-// SetConfig method of the LabelSource interface
-func (s *Source) SetConfig(source.Config) {}
-
-func (s Source) Discover() (source.FeatureLabels, error) {
+func (s *iommuSource) Discover() (source.FeatureLabels, error) {
 	features := source.FeatureLabels{}
 
 	// Check if any iommu devices are available
@@ -54,3 +54,7 @@ func (s Source) Discover() (source.FeatureLabels, error) {
 
 	return features, nil
 }
+
+func init() {
+	source.Register(&src)
+}
diff --git a/source/kernel/kernel.go b/source/kernel/kernel.go
index 88e8be782..045809135 100644
--- a/source/kernel/kernel.go
+++ b/source/kernel/kernel.go
@@ -47,21 +47,28 @@ func newDefaultConfig() *Config {
 	}
 }
 
-// Source implements LabelSource.
-type Source struct {
+// kernelSource implements the LabelSource and ConfigurableSource interfaces.
+type kernelSource struct {
 	config *Config
 }
 
-func (s *Source) Name() string { return Name }
+// Singleton source instance
+var (
+	src kernelSource
+	_   source.LabelSource        = &src
+	_   source.ConfigurableSource = &src
+)
+
+func (s *kernelSource) Name() string { return Name }
 
 // NewConfig method of the LabelSource interface
-func (s *Source) NewConfig() source.Config { return newDefaultConfig() }
+func (s *kernelSource) NewConfig() source.Config { return newDefaultConfig() }
 
 // GetConfig method of the LabelSource interface
-func (s *Source) GetConfig() source.Config { return s.config }
+func (s *kernelSource) GetConfig() source.Config { return s.config }
 
 // SetConfig method of the LabelSource interface
-func (s *Source) SetConfig(conf source.Config) {
+func (s *kernelSource) SetConfig(conf source.Config) {
 	switch v := conf.(type) {
 	case *Config:
 		s.config = v
@@ -70,7 +77,10 @@ func (s *Source) SetConfig(conf source.Config) {
 	}
 }
 
-func (s *Source) Discover() (source.FeatureLabels, error) {
+// Priority method of the LabelSource interface
+func (s *kernelSource) Priority() int { return 0 }
+
+func (s *kernelSource) Discover() (source.FeatureLabels, error) {
 	features := source.FeatureLabels{}
 
 	// Read kernel version
@@ -135,3 +145,7 @@ func parseVersion() (map[string]string, error) {
 
 	return version, nil
 }
+
+func init() {
+	source.Register(&src)
+}
diff --git a/source/local/local.go b/source/local/local.go
index 8fc9331f7..dc3427fe1 100644
--- a/source/local/local.go
+++ b/source/local/local.go
@@ -38,23 +38,23 @@ var (
 	hookDir         = "/etc/kubernetes/node-feature-discovery/source.d/"
 )
 
-// Source implements LabelSource.
-type Source struct{}
+// localSource implements the LabelSource interface.
+type localSource struct{}
+
+// Singleton source instance
+var (
+	src localSource
+	_   source.LabelSource = &src
+)
 
 // Name method of the LabelSource interface
-func (s Source) Name() string { return Name }
+func (s *localSource) Name() string { return Name }
 
-// NewConfig method of the LabelSource interface
-func (s *Source) NewConfig() source.Config { return nil }
-
-// GetConfig method of the LabelSource interface
-func (s *Source) GetConfig() source.Config { return nil }
-
-// SetConfig method of the LabelSource interface
-func (s *Source) SetConfig(source.Config) {}
+// Priority method of the LabelSource interface
+func (s *localSource) Priority() int { return 20 }
 
 // Discover method of the LabelSource interface
-func (s Source) Discover() (source.FeatureLabels, error) {
+func (s *localSource) Discover() (source.FeatureLabels, error) {
 	featuresFromHooks, err := getFeaturesFromHooks()
 	if err != nil {
 		klog.Error(err)
@@ -240,3 +240,7 @@ func getFileContent(fileName string) ([][]byte, error) {
 
 	return lines, nil
 }
+
+func init() {
+	source.Register(&src)
+}
diff --git a/source/memory/memory.go b/source/memory/memory.go
index 4311171ae..9fde92010 100644
--- a/source/memory/memory.go
+++ b/source/memory/memory.go
@@ -28,23 +28,23 @@ import (
 
 const Name = "memory"
 
-// Source implements LabelSource.
-type Source struct{}
+// memorySource implements the LabelSource interface.
+type memorySource struct{}
+
+// Singleton source instance
+var (
+	src memorySource
+	_   source.LabelSource = &src
+)
 
 // Name returns an identifier string for this feature source.
-func (s Source) Name() string { return Name }
+func (s *memorySource) Name() string { return Name }
 
-// NewConfig method of the LabelSource interface
-func (s *Source) NewConfig() source.Config { return nil }
-
-// GetConfig method of the LabelSource interface
-func (s *Source) GetConfig() source.Config { return nil }
-
-// SetConfig method of the LabelSource interface
-func (s *Source) SetConfig(source.Config) {}
+// Priority method of the LabelSource interface
+func (s *memorySource) Priority() int { return 0 }
 
 // Discover returns feature names for memory: numa if more than one memory node is present.
-func (s Source) Discover() (source.FeatureLabels, error) {
+func (s *memorySource) Discover() (source.FeatureLabels, error) {
 	features := source.FeatureLabels{}
 
 	// Detect NUMA
@@ -118,3 +118,7 @@ func detectNvdimm() (map[string]bool, error) {
 
 	return features, nil
 }
+
+func init() {
+	source.Register(&src)
+}
diff --git a/source/mock_LabelSource.go b/source/mock_LabelSource.go
index 82d55fdcc..96865c6fb 100644
--- a/source/mock_LabelSource.go
+++ b/source/mock_LabelSource.go
@@ -34,22 +34,6 @@ func (_m *MockLabelSource) Discover() (FeatureLabels, error) {
 	return r0, r1
 }
 
-// GetConfig provides a mock function with given fields:
-func (_m *MockLabelSource) GetConfig() Config {
-	ret := _m.Called()
-
-	var r0 Config
-	if rf, ok := ret.Get(0).(func() Config); ok {
-		r0 = rf()
-	} else {
-		if ret.Get(0) != nil {
-			r0 = ret.Get(0).(Config)
-		}
-	}
-
-	return r0
-}
-
 // Name provides a mock function with given fields:
 func (_m *MockLabelSource) Name() string {
 	ret := _m.Called()
@@ -64,23 +48,16 @@ func (_m *MockLabelSource) Name() string {
 	return r0
 }
 
-// NewConfig provides a mock function with given fields:
-func (_m *MockLabelSource) NewConfig() Config {
+// Priority provides a mock function with given fields:
+func (_m *MockLabelSource) Priority() int {
 	ret := _m.Called()
 
-	var r0 Config
-	if rf, ok := ret.Get(0).(func() Config); ok {
+	var r0 int
+	if rf, ok := ret.Get(0).(func() int); ok {
 		r0 = rf()
 	} else {
-		if ret.Get(0) != nil {
-			r0 = ret.Get(0).(Config)
-		}
+		r0 = ret.Get(0).(int)
 	}
 
 	return r0
 }
-
-// SetConfig provides a mock function with given fields: _a0
-func (_m *MockLabelSource) SetConfig(_a0 Config) {
-	_m.Called(_a0)
-}
diff --git a/source/network/network.go b/source/network/network.go
index 9a1748722..2ebf26778 100644
--- a/source/network/network.go
+++ b/source/network/network.go
@@ -41,23 +41,23 @@ const (
 
 const sysfsBaseDir = "class/net"
 
-// Source implements LabelSource.
-type Source struct{}
+// networkSource implements the LabelSource interface.
+type networkSource struct{}
+
+// Singleton source instance
+var (
+	src networkSource
+	_   source.LabelSource = &src
+)
 
 // Name returns an identifier string for this feature source.
-func (s Source) Name() string { return Name }
+func (s *networkSource) Name() string { return Name }
 
-// NewConfig method of the LabelSource interface
-func (s *Source) NewConfig() source.Config { return nil }
-
-// GetConfig method of the LabelSource interface
-func (s *Source) GetConfig() source.Config { return nil }
-
-// SetConfig method of the LabelSource interface
-func (s *Source) SetConfig(source.Config) {}
+// Priority method of the LabelSource interface
+func (s *networkSource) Priority() int { return 0 }
 
 // Discover returns feature names sriov-configured and sriov if SR-IOV capable NICs are present and/or SR-IOV virtual functions are configured on the node
-func (s Source) Discover() (source.FeatureLabels, error) {
+func (s *networkSource) Discover() (source.FeatureLabels, error) {
 	features := source.FeatureLabels{}
 
 	netInterfaces, err := ioutil.ReadDir(source.SysfsDir.Path(sysfsBaseDir))
@@ -128,3 +128,7 @@ func readIfFlags(name string) (uint64, error) {
 
 	return flags, nil
 }
+
+func init() {
+	source.Register(&src)
+}
diff --git a/source/pci/pci.go b/source/pci/pci.go
index a68f270ae..b100f0fbe 100644
--- a/source/pci/pci.go
+++ b/source/pci/pci.go
@@ -41,22 +41,29 @@ func newDefaultConfig() *Config {
 	}
 }
 
-// Source implements LabelSource.
-type Source struct {
+// pciSource implements the LabelSource and ConfigurableSource interfaces.
+type pciSource struct {
 	config *Config
 }
 
+// Singleton source instance
+var (
+	src pciSource
+	_   source.LabelSource        = &src
+	_   source.ConfigurableSource = &src
+)
+
 // Name returns the name of the feature source
-func (s Source) Name() string { return Name }
+func (s *pciSource) Name() string { return Name }
 
 // NewConfig method of the LabelSource interface
-func (s *Source) NewConfig() source.Config { return newDefaultConfig() }
+func (s *pciSource) NewConfig() source.Config { return newDefaultConfig() }
 
 // GetConfig method of the LabelSource interface
-func (s *Source) GetConfig() source.Config { return s.config }
+func (s *pciSource) GetConfig() source.Config { return s.config }
 
 // SetConfig method of the LabelSource interface
-func (s *Source) SetConfig(conf source.Config) {
+func (s *pciSource) SetConfig(conf source.Config) {
 	switch v := conf.(type) {
 	case *Config:
 		s.config = v
@@ -65,8 +72,11 @@ func (s *Source) SetConfig(conf source.Config) {
 	}
 }
 
+// Priority method of the LabelSource interface
+func (s *pciSource) Priority() int { return 0 }
+
 // Discover features
-func (s Source) Discover() (source.FeatureLabels, error) {
+func (s *pciSource) Discover() (source.FeatureLabels, error) {
 	features := source.FeatureLabels{}
 
 	// Construct a device label format, a sorted list of valid attributes
@@ -132,3 +142,7 @@ func (s Source) Discover() (source.FeatureLabels, error) {
 	}
 	return features, nil
 }
+
+func init() {
+	source.Register(&src)
+}
diff --git a/source/source.go b/source/source.go
index d70e10983..e490857f5 100644
--- a/source/source.go
+++ b/source/source.go
@@ -1,5 +1,5 @@
 /*
-Copyright 2017 The Kubernetes Authors.
+Copyright 2017-2021 The Kubernetes Authors.
 
 Licensed under the Apache License, Version 2.0 (the "License");
 you may not use this file except in compliance with the License.
@@ -16,20 +16,31 @@ limitations under the License.
 
 package source
 
-// FeatureLabelValue represents the value of one feature label
-type FeatureLabelValue interface{}
+import (
+	"fmt"
+)
 
-// FeatureLabels is a collection of feature labels
-type FeatureLabels map[string]FeatureLabelValue
+// Source is the base interface for all other source interfaces
+type Source interface {
+	// Name returns a friendly name for this source
+	Name() string
+}
 
 // LabelSource represents a source of node feature labels
 type LabelSource interface {
-	// Name returns a friendly name for this source
-	Name() string
+	Source
 
 	// Discover returns discovered feature labels
 	Discover() (FeatureLabels, error)
 
+	// Priority returns the priority of the source
+	Priority() int
+}
+
+// ConfigurableSource is an interface for a source that can be configured
+type ConfigurableSource interface {
+	Source
+
 	// NewConfig returns a new default config of the source
 	NewConfig() Config
 
@@ -40,6 +51,69 @@ type LabelSource interface {
 	SetConfig(Config)
 }
 
+// TestSource represents a source purposed for testing only
+type TestSource interface {
+	Source
+
+	// IsTestSource returns true if the source is not for production
+	IsTestSource() bool
+}
+
+// FeatureLabelValue represents the value of one feature label
+type FeatureLabelValue interface{}
+
+// FeatureLabels is a collection of feature labels
+type FeatureLabels map[string]FeatureLabelValue
+
 // Config is the generic interface for source configuration data
 type Config interface {
 }
+
+// sources contain all registered sources
+var sources = make(map[string]Source)
+
+// RegisterSource registers a source
+func Register(s Source) {
+	if name, ok := sources[s.Name()]; ok {
+		panic(fmt.Sprintf("source %q already registered", name))
+	}
+	sources[s.Name()] = s
+}
+
+// GetLabelSource a registered label source
+func GetLabelSource(name string) LabelSource {
+	if s, ok := sources[name].(LabelSource); ok {
+		return s
+	}
+	return nil
+}
+
+// GetAllLabelSources returns all registered label sources
+func GetAllLabelSources() map[string]LabelSource {
+	all := make(map[string]LabelSource)
+	for k, v := range sources {
+		if s, ok := v.(LabelSource); ok {
+			all[k] = s
+		}
+	}
+	return all
+}
+
+// GetConfigurableSource a registered configurable source
+func GetConfigurableSource(name string) ConfigurableSource {
+	if s, ok := sources[name].(ConfigurableSource); ok {
+		return s
+	}
+	return nil
+}
+
+// GetAllConfigurableSources returns all registered configurable sources
+func GetAllConfigurableSources() map[string]ConfigurableSource {
+	all := make(map[string]ConfigurableSource)
+	for k, v := range sources {
+		if s, ok := v.(ConfigurableSource); ok {
+			all[k] = s
+		}
+	}
+	return all
+}
diff --git a/source/source_test.go b/source/source_test.go
new file mode 100644
index 000000000..c8a6980ae
--- /dev/null
+++ b/source/source_test.go
@@ -0,0 +1,63 @@
+/*
+Copyright 2021 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package source_test
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+
+	source "sigs.k8s.io/node-feature-discovery/source"
+
+	// Register all source packages
+	_ "sigs.k8s.io/node-feature-discovery/source/cpu"
+	_ "sigs.k8s.io/node-feature-discovery/source/custom"
+	_ "sigs.k8s.io/node-feature-discovery/source/fake"
+	_ "sigs.k8s.io/node-feature-discovery/source/iommu"
+	_ "sigs.k8s.io/node-feature-discovery/source/kernel"
+	_ "sigs.k8s.io/node-feature-discovery/source/local"
+	_ "sigs.k8s.io/node-feature-discovery/source/memory"
+	_ "sigs.k8s.io/node-feature-discovery/source/network"
+	_ "sigs.k8s.io/node-feature-discovery/source/pci"
+	_ "sigs.k8s.io/node-feature-discovery/source/storage"
+	_ "sigs.k8s.io/node-feature-discovery/source/system"
+	_ "sigs.k8s.io/node-feature-discovery/source/usb"
+)
+
+func TestLabelSources(t *testing.T) {
+	sources := source.GetAllLabelSources()
+	assert.NotZero(t, len(sources))
+
+	for n, s := range sources {
+		assert.Equalf(t, n, s.Name(), "testing labelsource %q failed", n)
+	}
+}
+
+func TestConfigurableSources(t *testing.T) {
+	sources := source.GetAllConfigurableSources()
+	assert.NotZero(t, len(sources))
+
+	for n, s := range sources {
+		assert.Equalf(t, n, s.Name(), "testing ConfigurableSource %q failed", n)
+
+		c := s.NewConfig()
+		s.SetConfig(c)
+		rc := s.GetConfig()
+
+		assert.Equalf(t, c, rc, "testing ConfigurableSource %q failed", n)
+	}
+}
diff --git a/source/storage/storage.go b/source/storage/storage.go
index a2ae032fc..34383340a 100644
--- a/source/storage/storage.go
+++ b/source/storage/storage.go
@@ -1,5 +1,5 @@
 /*
-Copyright 2018 The Kubernetes Authors.
+Copyright 2018-2021 The Kubernetes Authors.
 
 Licensed under the Apache License, Version 2.0 (the "License");
 you may not use this file except in compliance with the License.
@@ -25,23 +25,23 @@ import (
 
 const Name = "storage"
 
-// Source implements LabelSource.
-type Source struct{}
+// storageSource implements the LabelSource interface.
+type storageSource struct{}
+
+// Singleton source instance
+var (
+	src storageSource
+	_   source.LabelSource = &src
+)
 
 // Name returns an identifier string for this feature source.
-func (s Source) Name() string { return Name }
+func (s *storageSource) Name() string { return Name }
 
-// NewConfig method of the LabelSource interface
-func (s *Source) NewConfig() source.Config { return nil }
-
-// GetConfig method of the LabelSource interface
-func (s *Source) GetConfig() source.Config { return nil }
-
-// SetConfig method of the LabelSource interface
-func (s *Source) SetConfig(source.Config) {}
+// Priority method of the LabelSource interface
+func (s *storageSource) Priority() int { return 0 }
 
 // Discover returns feature names for storage: nonrotationaldisk if any SSD drive present.
-func (s Source) Discover() (source.FeatureLabels, error) {
+func (s *storageSource) Discover() (source.FeatureLabels, error) {
 	features := source.FeatureLabels{}
 
 	// Check if there is any non-rotational block devices attached to the node
@@ -62,3 +62,7 @@ func (s Source) Discover() (source.FeatureLabels, error) {
 	}
 	return features, nil
 }
+
+func init() {
+	source.Register(&src)
+}
diff --git a/source/system/system.go b/source/system/system.go
index 889aa8ceb..2ee4ac029 100644
--- a/source/system/system.go
+++ b/source/system/system.go
@@ -34,21 +34,21 @@ var osReleaseFields = [...]string{
 
 const Name = "system"
 
-// Source implements LabelSource.
-type Source struct{}
+// systemSource implements the LabelSource interface.
+type systemSource struct{}
 
-func (s Source) Name() string { return Name }
+// Singleton source instance
+var (
+	src systemSource
+	_   source.LabelSource = &src
+)
 
-// NewConfig method of the LabelSource interface
-func (s *Source) NewConfig() source.Config { return nil }
+func (s *systemSource) Name() string { return Name }
 
-// GetConfig method of the LabelSource interface
-func (s *Source) GetConfig() source.Config { return nil }
+// Priority method of the LabelSource interface
+func (s *systemSource) Priority() int { return 0 }
 
-// SetConfig method of the LabelSource interface
-func (s *Source) SetConfig(source.Config) {}
-
-func (s Source) Discover() (source.FeatureLabels, error) {
+func (s *systemSource) Discover() (source.FeatureLabels, error) {
 	features := source.FeatureLabels{}
 
 	release, err := parseOSRelease()
@@ -112,3 +112,7 @@ func splitVersion(version string) map[string]string {
 	}
 	return components
 }
+
+func init() {
+	source.Register(&src)
+}
diff --git a/source/usb/usb.go b/source/usb/usb.go
index 81b8003ef..80774fbec 100644
--- a/source/usb/usb.go
+++ b/source/usb/usb.go
@@ -44,22 +44,29 @@ func newDefaultConfig() *Config {
 	}
 }
 
-// Source implements LabelSource.
-type Source struct {
+// usbSource implements the LabelSource and ConfigurableSource interfaces.
+type usbSource struct {
 	config *Config
 }
 
+// Singleton source instance
+var (
+	src usbSource
+	_   source.LabelSource        = &src
+	_   source.ConfigurableSource = &src
+)
+
 // Name returns the name of the feature source
-func (s Source) Name() string { return Name }
+func (s *usbSource) Name() string { return Name }
 
 // NewConfig method of the LabelSource interface
-func (s *Source) NewConfig() source.Config { return newDefaultConfig() }
+func (s *usbSource) NewConfig() source.Config { return newDefaultConfig() }
 
 // GetConfig method of the LabelSource interface
-func (s *Source) GetConfig() source.Config { return s.config }
+func (s *usbSource) GetConfig() source.Config { return s.config }
 
 // SetConfig method of the LabelSource interface
-func (s *Source) SetConfig(conf source.Config) {
+func (s *usbSource) SetConfig(conf source.Config) {
 	switch v := conf.(type) {
 	case *Config:
 		s.config = v
@@ -68,8 +75,11 @@ func (s *Source) SetConfig(conf source.Config) {
 	}
 }
 
+// Priority method of the LabelSource interface
+func (s *usbSource) Priority() int { return 0 }
+
 // Discover features
-func (s Source) Discover() (source.FeatureLabels, error) {
+func (s *usbSource) Discover() (source.FeatureLabels, error) {
 	features := source.FeatureLabels{}
 
 	// Construct a device label format, a sorted list of valid attributes
@@ -127,3 +137,7 @@ func (s Source) Discover() (source.FeatureLabels, error) {
 	}
 	return features, nil
 }
+
+func init() {
+	source.Register(&src)
+}