nrt: cache: add support for dedicated informer

Add an option to create and use a separate informer
to get unfiltered pod listing from the apiserver.

Due to mismatched view with respect to the kubelet,
the plugin needs access to pod in terminal phase
which are not deleted to make sure the reconciliation
is done correctly.

xref: #598
xref: kubernetes/kubernetes#119423

Signed-off-by: Francesco Romani <[email protected]>

Author: ffromani

apis/config/types.go

@@ -176,6 +176,14 @@ const (
 	CacheResyncOnlyExclusiveResources CacheResyncMethod = "OnlyExclusiveResources"
 )
 
+// CacheInformerMode is a "string" type
+type CacheInformerMode string
+
+const (
+	CacheInformerShared    CacheInformerMode = "Shared"
+	CacheInformerDedicated CacheInformerMode = "Dedicated"
+)
+
 // NodeResourceTopologyCache define configuration details for the NodeResourceTopology cache.
 type NodeResourceTopologyCache struct {
 	// ForeignPodsDetect sets how foreign pods should be handled.
@@ -192,6 +200,11 @@ type NodeResourceTopologyCache struct {
 	// Has no effect if caching is disabled (CacheResyncPeriod is zero) or if DiscardReservedNodes
 	// is enabled. "Autodetect" is the default, reads hint from NRT objects. Fallback is "All".
 	ResyncMethod *CacheResyncMethod
+	// InformerMode controls the channel the cache uses to get updates about pods.
+	// "Shared" uses the default settings; "Dedicated" creates a specific subscription which is
+	// guaranteed to best suit the cache needs, at cost of one extra connection.
+	// If unspecified, default is "Dedicated"
+	InformerMode *CacheInformerMode
 }
 
 // +k8s:deepcopy-gen:interfaces=k8s.io/apimachinery/pkg/runtime.Object

apis/config/v1/defaults.go

@@ -89,6 +89,8 @@ var (
 
 	defaultResyncMethod = CacheResyncAutodetect
 
+	defaultInformerMode = CacheInformerDedicated
+
 	// Defaults for NetworkOverhead
 	// DefaultWeightsName contains the default costs to be used by networkAware plugins
 	DefaultWeightsName = "UserDefined"
@@ -200,6 +202,9 @@ func SetDefaults_NodeResourceTopologyMatchArgs(obj *NodeResourceTopologyMatchArg
 	if obj.Cache.ResyncMethod == nil {
 		obj.Cache.ResyncMethod = &defaultResyncMethod
 	}
+	if obj.Cache.InformerMode == nil {
+		obj.Cache.InformerMode = &defaultInformerMode
+	}
 }
 
 // SetDefaults_PreemptionTolerationArgs reuses SetDefaults_DefaultPreemptionArgs

apis/config/v1/defaults_test.go

@@ -205,6 +205,7 @@ func TestSchedulingDefaults(t *testing.T) {
 				Cache: &NodeResourceTopologyCache{
 					ForeignPodsDetect: &defaultForeignPodsDetect,
 					ResyncMethod:      &defaultResyncMethod,
+					InformerMode:      &defaultInformerMode,
 				},
 			},
 		},

apis/config/v1/types.go

@@ -174,6 +174,14 @@ const (
 	CacheResyncOnlyExclusiveResources CacheResyncMethod = "OnlyExclusiveResources"
 )
 
+// CacheInformerMode is a "string" type
+type CacheInformerMode string
+
+const (
+	CacheInformerShared    CacheInformerMode = "Shared"
+	CacheInformerDedicated CacheInformerMode = "Dedicated"
+)
+
 // NodeResourceTopologyCache define configuration details for the NodeResourceTopology cache.
 type NodeResourceTopologyCache struct {
 	// ForeignPodsDetect sets how foreign pods should be handled.
@@ -190,6 +198,11 @@ type NodeResourceTopologyCache struct {
 	// Has no effect if caching is disabled (CacheResyncPeriod is zero) or if DiscardReservedNodes
 	// is enabled. "Autodetect" is the default, reads hint from NRT objects. Fallback is "All".
 	ResyncMethod *CacheResyncMethod `json:"resyncMethod,omitempty"`
+	// InformerMode controls the channel the cache uses to get updates about pods.
+	// "Shared" uses the default settings; "Dedicated" creates a specific subscription which is
+	// guaranteed to best suit the cache needs, at cost of one extra connection.
+	// If unspecified, default is "Dedicated"
+	InformerMode *CacheInformerMode `json:"informerMode,omitempty"`
 }
 
 // +k8s:deepcopy-gen:interfaces=k8s.io/apimachinery/pkg/runtime.Object

apis/config/v1/zz_generated.conversion.go

@@ -89,6 +89,8 @@ var (
 
 	defaultResyncMethod = CacheResyncAutodetect
 
+	defaultInformerMode = CacheInformerDedicated
+
 	// Defaults for NetworkOverhead
 	// DefaultWeightsName contains the default costs to be used by networkAware plugins
 	DefaultWeightsName = "UserDefined"
@@ -200,6 +202,9 @@ func SetDefaults_NodeResourceTopologyMatchArgs(obj *NodeResourceTopologyMatchArg
 	if obj.Cache.ResyncMethod == nil {
 		obj.Cache.ResyncMethod = &defaultResyncMethod
 	}
+	if obj.Cache.InformerMode == nil {
+		obj.Cache.InformerMode = &defaultInformerMode
+	}
 }
 
 // SetDefaults_PreemptionTolerationArgs reuses SetDefaults_DefaultPreemptionArgs

apis/config/v1/zz_generated.deepcopy.go

@@ -205,6 +205,7 @@ func TestSchedulingDefaults(t *testing.T) {
 				Cache: &NodeResourceTopologyCache{
 					ForeignPodsDetect: &defaultForeignPodsDetect,
 					ResyncMethod:      &defaultResyncMethod,
+					InformerMode:      &defaultInformerMode,
 				},
 			},
 		},

apis/config/v1beta3/defaults.go

@@ -174,6 +174,14 @@ const (
 	CacheResyncOnlyExclusiveResources CacheResyncMethod = "OnlyExclusiveResources"
 )
 
+// CacheInformerMode is a "string" type
+type CacheInformerMode string
+
+const (
+	CacheInformerShared    CacheInformerMode = "Shared"
+	CacheInformerDedicated CacheInformerMode = "Dedicated"
+)
+
 // NodeResourceTopologyCache define configuration details for the NodeResourceTopology cache.
 type NodeResourceTopologyCache struct {
 	// ForeignPodsDetect sets how foreign pods should be handled.
@@ -190,6 +198,11 @@ type NodeResourceTopologyCache struct {
 	// Has no effect if caching is disabled (CacheResyncPeriod is zero) or if DiscardReservedNodes
 	// is enabled. "Autodetect" is the default, reads hint from NRT objects. Fallback is "All".
 	ResyncMethod *CacheResyncMethod `json:"resyncMethod,omitempty"`
+	// InformerMode controls the channel the cache uses to get updates about pods.
+	// "Shared" uses the default settings; "Dedicated" creates a specific subscription which is
+	// guaranteed to best suit the cache needs, at cost of one extra connection.
+	// If unspecified, default is "Dedicated"
+	InformerMode *CacheInformerMode `json:"informerMode,omitempty"`
 }
 
 // +k8s:deepcopy-gen:interfaces=k8s.io/apimachinery/pkg/runtime.Object