operator: Add memberlist IPv6 support

operator/CHANGELOG.md

@@ -1,5 +1,6 @@
 ## Main
 
+- [10562](https://github.com/grafana/loki/pull/10562) **periklis**: Add memberlist IPv6 support
 - [10720](https://github.com/grafana/loki/pull/10720) **JoaoBraveCoding**: Change default replication factor of 1x.medium to 2
 - [10600](https://github.com/grafana/loki/pull/10600) **periklis**: Update Loki operand to v2.9.1
 - [10545](https://github.com/grafana/loki/pull/10545) **xperimental**: Update gateway arguments to enable namespace extraction

operator/apis/loki/v1/lokistack_types.go

@@ -437,6 +437,16 @@ type MemberListSpec struct {
 	// +kubebuilder:validation:optional
 	// +operator-sdk:csv:customresourcedefinitions:type=spec,xDescriptors={"urn:alm:descriptor:com.tectonic.ui:select:default","urn:alm:descriptor:com.tectonic.ui:select:podIP"},displayName="Instance Address"
 	InstanceAddrType InstanceAddrType `json:"instanceAddrType,omitempty"`
+
+	// EnableIPv6 enables IPv6 support for the memberlist based hash ring.
+	//
+	// Currently this also forces the instanceAddrType to podIP to avoid local address lookup
+	// for the memberlist.
+	//
+	// +optional
+	// +kubebuilder:validation:Optional
+	// +operator-sdk:csv:customresourcedefinitions:type=spec,xDescriptors="urn:alm:descriptor:com.tectonic.ui:booleanSwitch",displayName="Enable IPv6"
+	EnableIPv6 bool `json:"enableIPv6,omitempty"`
 }
 
 // HashRingSpec defines the hash ring configuration

operator/apis/loki/v1/v1.go

@@ -81,6 +81,8 @@ var (
 	ErrReplicationFactorToZonesRatio = errors.New("replication factor is greater than the number of available zones")
 	// ErrReplicationSpecConflict when both the ReplicationSpec and depricated ReplicationFactor are used.
 	ErrReplicationSpecConflict = errors.New("replicationSpec and replicationFactor (deprecated) cannot be used at the same time")
+	// ErrIPv6InstanceAddrTypeNotAllowed when the default InstanceAddrType is used with enableIPv6.
+	ErrIPv6InstanceAddrTypeNotAllowed = errors.New(`instanceAddrType "default" cannot be used with enableIPv6 at the same time`)
 
 	// ErrRuleMustMatchNamespace indicates that an expression used in an alerting or recording rule is missing
 	// matchers for a namespace.

operator/bundle/community-openshift/manifests/loki-operator.clusterserviceversion.yaml

@@ -150,7 +150,7 @@ metadata:
     categories: OpenShift Optional, Logging & Tracing
     certified: "false"
     containerImage: docker.io/grafana/loki-operator:0.4.0
-    createdAt: "2023-09-15T08:01:24Z"
+    createdAt: "2023-09-28T10:58:47Z"
     description: The Community Loki Operator provides Kubernetes native deployment
       and management of Loki and related logging components.
     operators.operatorframework.io/builder: operator-sdk-unknown
@@ -265,6 +265,13 @@ spec:
       - description: MemberList configuration spec
         displayName: Memberlist Config
         path: hashRing.memberlist
+      - description: "EnableIPv6 enables IPv6 support for the memberlist based hash
+          ring. \n Currently this also forces the instanceAddrType to podIP to avoid
+          local address lookup for the memberlist."
+        displayName: Enable IPv6
+        path: hashRing.memberlist.enableIPv6
+        x-descriptors:
+        - urn:alm:descriptor:com.tectonic.ui:booleanSwitch
       - description: InstanceAddrType defines the type of address to use to advertise
           to the ring. Defaults to the first address from any private network interfaces
           of the current pod. Alternatively the public pod IP can be used in case

operator/bundle/community-openshift/manifests/loki.grafana.com_lokistacks.yaml

@@ -61,6 +61,11 @@ spec:
                   memberlist:
                     description: MemberList configuration spec
                     properties:
+                      enableIPv6:
+                        description: "EnableIPv6 enables IPv6 support for the memberlist
+                          based hash ring. \n Currently this also forces the instanceAddrType
+                          to podIP to avoid local address lookup for the memberlist."
+                        type: boolean
                       instanceAddrType:
                         description: InstanceAddrType defines the type of address
                           to use to advertise to the ring. Defaults to the first address

operator/bundle/community/manifests/loki-operator.clusterserviceversion.yaml

@@ -150,7 +150,7 @@ metadata:
     categories: OpenShift Optional, Logging & Tracing
     certified: "false"
     containerImage: docker.io/grafana/loki-operator:0.4.0
-    createdAt: "2023-09-15T08:01:22Z"
+    createdAt: "2023-09-28T10:58:45Z"
     description: The Community Loki Operator provides Kubernetes native deployment
       and management of Loki and related logging components.
     operators.operatorframework.io/builder: operator-sdk-unknown
@@ -265,6 +265,13 @@ spec:
       - description: MemberList configuration spec
         displayName: Memberlist Config
         path: hashRing.memberlist
+      - description: "EnableIPv6 enables IPv6 support for the memberlist based hash
+          ring. \n Currently this also forces the instanceAddrType to podIP to avoid
+          local address lookup for the memberlist."
+        displayName: Enable IPv6
+        path: hashRing.memberlist.enableIPv6
+        x-descriptors:
+        - urn:alm:descriptor:com.tectonic.ui:booleanSwitch
       - description: InstanceAddrType defines the type of address to use to advertise
           to the ring. Defaults to the first address from any private network interfaces
           of the current pod. Alternatively the public pod IP can be used in case

operator/bundle/community/manifests/loki.grafana.com_lokistacks.yaml

@@ -61,6 +61,11 @@ spec:
                   memberlist:
                     description: MemberList configuration spec
                     properties:
+                      enableIPv6:
+                        description: "EnableIPv6 enables IPv6 support for the memberlist
+                          based hash ring. \n Currently this also forces the instanceAddrType
+                          to podIP to avoid local address lookup for the memberlist."
+                        type: boolean
                       instanceAddrType:
                         description: InstanceAddrType defines the type of address
                           to use to advertise to the ring. Defaults to the first address

operator/bundle/openshift/manifests/loki-operator.clusterserviceversion.yaml

@@ -150,7 +150,7 @@ metadata:
     categories: OpenShift Optional, Logging & Tracing
     certified: "false"
     containerImage: quay.io/openshift-logging/loki-operator:0.1.0
-    createdAt: "2023-09-15T08:01:27Z"
+    createdAt: "2023-09-28T10:58:49Z"
     description: |
       The Loki Operator for OCP provides a means for configuring and managing a Loki stack for cluster logging.
       ## Prerequisites and Requirements
@@ -278,6 +278,13 @@ spec:
       - description: MemberList configuration spec
         displayName: Memberlist Config
         path: hashRing.memberlist
+      - description: "EnableIPv6 enables IPv6 support for the memberlist based hash
+          ring. \n Currently this also forces the instanceAddrType to podIP to avoid
+          local address lookup for the memberlist."
+        displayName: Enable IPv6
+        path: hashRing.memberlist.enableIPv6
+        x-descriptors:
+        - urn:alm:descriptor:com.tectonic.ui:booleanSwitch
       - description: InstanceAddrType defines the type of address to use to advertise
           to the ring. Defaults to the first address from any private network interfaces
           of the current pod. Alternatively the public pod IP can be used in case

operator/bundle/openshift/manifests/loki.grafana.com_lokistacks.yaml

@@ -61,6 +61,11 @@ spec:
                   memberlist:
                     description: MemberList configuration spec
                     properties:
+                      enableIPv6:
+                        description: "EnableIPv6 enables IPv6 support for the memberlist
+                          based hash ring. \n Currently this also forces the instanceAddrType
+                          to podIP to avoid local address lookup for the memberlist."
+                        type: boolean
                       instanceAddrType:
                         description: InstanceAddrType defines the type of address
                           to use to advertise to the ring. Defaults to the first address

operator/config/crd/bases/loki.grafana.com_lokistacks.yaml

@@ -44,6 +44,11 @@ spec:
                   memberlist:
                     description: MemberList configuration spec
                     properties:
+                      enableIPv6:
+                        description: "EnableIPv6 enables IPv6 support for the memberlist
+                          based hash ring. \n Currently this also forces the instanceAddrType
+                          to podIP to avoid local address lookup for the memberlist."
+                        type: boolean
                       instanceAddrType:
                         description: InstanceAddrType defines the type of address
                           to use to advertise to the ring. Defaults to the first address

operator/config/manifests/community-openshift/bases/loki-operator.clusterserviceversion.yaml

@@ -178,6 +178,13 @@ spec:
       - description: MemberList configuration spec
         displayName: Memberlist Config
         path: hashRing.memberlist
+      - description: "EnableIPv6 enables IPv6 support for the memberlist based hash
+          ring. \n Currently this also forces the instanceAddrType to podIP to avoid
+          local address lookup for the memberlist."
+        displayName: Enable IPv6
+        path: hashRing.memberlist.enableIPv6
+        x-descriptors:
+        - urn:alm:descriptor:com.tectonic.ui:booleanSwitch
       - description: InstanceAddrType defines the type of address to use to advertise
           to the ring. Defaults to the first address from any private network interfaces
           of the current pod. Alternatively the public pod IP can be used in case

operator/config/manifests/community/bases/loki-operator.clusterserviceversion.yaml

@@ -178,6 +178,13 @@ spec:
       - description: MemberList configuration spec
         displayName: Memberlist Config
         path: hashRing.memberlist
+      - description: "EnableIPv6 enables IPv6 support for the memberlist based hash
+          ring. \n Currently this also forces the instanceAddrType to podIP to avoid
+          local address lookup for the memberlist."
+        displayName: Enable IPv6
+        path: hashRing.memberlist.enableIPv6
+        x-descriptors:
+        - urn:alm:descriptor:com.tectonic.ui:booleanSwitch
       - description: InstanceAddrType defines the type of address to use to advertise
           to the ring. Defaults to the first address from any private network interfaces
           of the current pod. Alternatively the public pod IP can be used in case

operator/config/manifests/openshift/bases/loki-operator.clusterserviceversion.yaml

@@ -190,6 +190,13 @@ spec:
       - description: MemberList configuration spec
         displayName: Memberlist Config
         path: hashRing.memberlist
+      - description: "EnableIPv6 enables IPv6 support for the memberlist based hash
+          ring. \n Currently this also forces the instanceAddrType to podIP to avoid
+          local address lookup for the memberlist."
+        displayName: Enable IPv6
+        path: hashRing.memberlist.enableIPv6
+        x-descriptors:
+        - urn:alm:descriptor:com.tectonic.ui:booleanSwitch
       - description: InstanceAddrType defines the type of address to use to advertise
           to the ring. Defaults to the first address from any private network interfaces
           of the current pod. Alternatively the public pod IP can be used in case

operator/docs/operator/api.md

@@ -2246,6 +2246,20 @@ Alternatively the public pod IP can be used in case private networks (RFC 1918 a
 are not available.</p>
 </td>
 </tr>
+<tr>
+<td>
+<code>enableIPv6</code><br/>
+<em>
+bool
+</em>
+</td>
+<td>
+<em>(Optional)</em>
+<p>EnableIPv6 enables IPv6 support for the memberlist based hash ring.</p>
+<p>Currently this also forces the instanceAddrType to podIP to avoid local address lookup
+for the memberlist.</p>
+</td>
+</tr>
 </tbody>
 </table>
 

operator/internal/manifests/config.go

@@ -259,19 +259,31 @@ func alertManagerConfig(spec *lokiv1.AlertManagerSpec) *config.AlertManagerConfi
 }
 
 func gossipRingConfig(stackName, stackNs string, spec *lokiv1.HashRingSpec, replication *lokiv1.ReplicationSpec) config.GossipRing {
-	var instanceAddr string
+	var (
+		instanceAddr string
+		enableIPv6   bool
+	)
 	if spec != nil && spec.Type == lokiv1.HashRingMemberList && spec.MemberList != nil {
 		switch spec.MemberList.InstanceAddrType {
 		case lokiv1.InstanceAddrPodIP:
-			instanceAddr = fmt.Sprintf("${%s}", gossipInstanceAddrEnvVarName)
+			instanceAddr = gossipInstanceAddrEnvVarTemplate
 		case lokiv1.InstanceAddrDefault:
 			// Do nothing use loki defaults
 		default:
 			// Do nothing use loki defaults
 		}
+
+		// Always default to use the pod IP address when IPv6 enabled to ensure:
+		// - On Single Stack IPv6: Skip interface checking
+		// - On Dual Stack IPv4/6: Eliminate duplicate memberlist node registration
+		if spec.MemberList.EnableIPv6 {
+			enableIPv6 = true
+			instanceAddr = gossipInstanceAddrEnvVarTemplate
+		}
 	}
 
 	return config.GossipRing{
+		EnableIPv6:                     enableIPv6,
 		InstanceAddr:                   instanceAddr,
 		InstancePort:                   grpcPort,
 		BindPort:                       gossipPort,

operator/internal/manifests/config_test.go

@@ -280,6 +280,43 @@ func TestConfigOptions_GossipRingConfig(t *testing.T) {
 				MembersDiscoveryAddr:           "my-stack-gossip-ring.my-ns.svc.cluster.local",
 			},
 		},
+		{
+			desc: "IPv6 enabled with default instance address type",
+			spec: lokiv1.LokiStackSpec{
+				HashRing: &lokiv1.HashRingSpec{
+					Type: lokiv1.HashRingMemberList,
+					MemberList: &lokiv1.MemberListSpec{
+						EnableIPv6: true,
+					},
+				},
+			},
+			wantOptions: config.GossipRing{
+				EnableIPv6:           true,
+				InstanceAddr:         "${HASH_RING_INSTANCE_ADDR}",
+				InstancePort:         9095,
+				BindPort:             7946,
+				MembersDiscoveryAddr: "my-stack-gossip-ring.my-ns.svc.cluster.local",
+			},
+		},
+		{
+			desc: "IPv6 enabled with podIP instance address type",
+			spec: lokiv1.LokiStackSpec{
+				HashRing: &lokiv1.HashRingSpec{
+					Type: lokiv1.HashRingMemberList,
+					MemberList: &lokiv1.MemberListSpec{
+						EnableIPv6:       true,
+						InstanceAddrType: lokiv1.InstanceAddrPodIP,
+					},
+				},
+			},
+			wantOptions: config.GossipRing{
+				EnableIPv6:           true,
+				InstanceAddr:         "${HASH_RING_INSTANCE_ADDR}",
+				InstancePort:         9095,
+				BindPort:             7946,
+				MembersDiscoveryAddr: "my-stack-gossip-ring.my-ns.svc.cluster.local",
+			},
+		},
 	}
 	for _, tc := range tt {
 		tc := tc